A sustainable solution for electricity generation using thermo-acoustic technology
- Machesa, M.G.K., Tartibu, L.K., Kallon, D.V.
- Authors: Machesa, M.G.K. , Tartibu, L.K. , Kallon, D.V.
- Date: 2017
- Subjects: Thermo-acoustic , Sound , Electricity
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250750 , uj:26136 , Citation: Machesa, M.G.K., Tartibu, L.K. & Kallon, D.V. 2017. A sustainable solution for electricity generation using thermo-acoustic technology.
- Description: Abstract: This work explores the use of thermo-acoustic system as alternative technology for electricity generation. This technology is proposed as a potential replacement for low-cost electrical power generation because of its simplicity and lack of moving parts. Thermo-acoustic generators providing clean electrical energy to power small appliances. The energy conversion from heat into sound wave is done within thermo-acoustic engine. The latter is coupled to a linear alternator for electricity generation. The study investigates the influence of the geometrical configuration of the device on to the whole functionality of the generator. The paper studies the technology through experimental trails performed using a simple arrangement to simulate the generator. The experiment is conducted in phases; the first phase identifies the best geometrical configuration of the thermo-acoustic engine by measuring the sound pressure level and the temperatures. The second phase consist of measuring the electricity generated using a Loudspeaker. The results obtained show the potential for this sustainable solution for electricity generation.
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- Authors: Machesa, M.G.K. , Tartibu, L.K. , Kallon, D.V.
- Date: 2017
- Subjects: Thermo-acoustic , Sound , Electricity
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250750 , uj:26136 , Citation: Machesa, M.G.K., Tartibu, L.K. & Kallon, D.V. 2017. A sustainable solution for electricity generation using thermo-acoustic technology.
- Description: Abstract: This work explores the use of thermo-acoustic system as alternative technology for electricity generation. This technology is proposed as a potential replacement for low-cost electrical power generation because of its simplicity and lack of moving parts. Thermo-acoustic generators providing clean electrical energy to power small appliances. The energy conversion from heat into sound wave is done within thermo-acoustic engine. The latter is coupled to a linear alternator for electricity generation. The study investigates the influence of the geometrical configuration of the device on to the whole functionality of the generator. The paper studies the technology through experimental trails performed using a simple arrangement to simulate the generator. The experiment is conducted in phases; the first phase identifies the best geometrical configuration of the thermo-acoustic engine by measuring the sound pressure level and the temperatures. The second phase consist of measuring the electricity generated using a Loudspeaker. The results obtained show the potential for this sustainable solution for electricity generation.
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A sustainable solution for refrigeration using Thermo-acoustic technology
- Authors: Tartibu, L.K.
- Date: 2016
- Subjects: Thermo-acoustic refrigerator , Stack , Honeycomb ceramic
- Language: English
- Type: Conference proceedings
- Identifier: http://ujcontent.uj.ac.za8080/10210/390307 , http://hdl.handle.net/10210/217019 , uj:21586 , Citation: Tartibu, L.K. 2016. A sustainable solution for refrigeration using Thermo-acoustic technology.
- Description: Abstract: This work explores the use of thermo-acoustic coolers as alternative technology for refrigeration. A valid experimental evidence on the influence of the geometry of the honeycomb ceramic stack on the performance of thermosacoustic refrigerators is described. Sixteen cordierite honeycomb ceramic stacks with square cross sections having four different lengths of 26 mm, 48 mm, 70 mm and 100 mm are considered. Measurements are taken at six different locations of the stack hot ends from the pressure antinode, namely 100 mm, 200 mm, 300 mm, 400 mm, 500 mm and 600 mm respectively. Measurement of temperature difference across the stack ends at steady state for different stack geometries are used to measure the performance of the device. The results with atmospheric air demonstrates the influence of the stack geometry on the cooling power and shows that some its geometrical parameters are interdependent.
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- Authors: Tartibu, L.K.
- Date: 2016
- Subjects: Thermo-acoustic refrigerator , Stack , Honeycomb ceramic
- Language: English
- Type: Conference proceedings
- Identifier: http://ujcontent.uj.ac.za8080/10210/390307 , http://hdl.handle.net/10210/217019 , uj:21586 , Citation: Tartibu, L.K. 2016. A sustainable solution for refrigeration using Thermo-acoustic technology.
- Description: Abstract: This work explores the use of thermo-acoustic coolers as alternative technology for refrigeration. A valid experimental evidence on the influence of the geometry of the honeycomb ceramic stack on the performance of thermosacoustic refrigerators is described. Sixteen cordierite honeycomb ceramic stacks with square cross sections having four different lengths of 26 mm, 48 mm, 70 mm and 100 mm are considered. Measurements are taken at six different locations of the stack hot ends from the pressure antinode, namely 100 mm, 200 mm, 300 mm, 400 mm, 500 mm and 600 mm respectively. Measurement of temperature difference across the stack ends at steady state for different stack geometries are used to measure the performance of the device. The results with atmospheric air demonstrates the influence of the stack geometry on the cooling power and shows that some its geometrical parameters are interdependent.
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Design and construction of a thermoacoustically driven thermoacoustic refrigerator
- Alcock, A.C., Tartibu, L.K., Jen, T.C.
- Authors: Alcock, A.C. , Tartibu, L.K. , Jen, T.C.
- Date: 2017
- Subjects: Design , Thermoacoustic refrigeration , TADTAR
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250780 , uj:26139 , Citation: Alcock, A.C., Tartibu, L.K. & Jen, T.C. 2017. Design and construction of a thermoacoustically driven thermoacoustic refrigerator.
- Description: Abstract: This work describes the design and construction of a standing wave Thermoacoustically Driven Thermoacoustic Refrigerator (TADTAR). The thermoacoustic cooler is proposed in this study as an alternative sustainable solution to current issues with vapor compression refrigerators, due to its environmentally friendlier attributes and its solar energy driven capabilities. However, one of the main hindrances to the expansion of this technology is its current lack of efficiency and performance closely related to the designing of the device. Hence, a model has been designed and constructed to perform an experimental investigation of the device’s performance at the University of Johannesburg. This model will mainly be used to investigate the dynamics of the TADTAR arrangement. The TADTAR consists of two thermoacoustic systems namely a thermoacoustic engine coupled to a thermoacoustic refrigerator. The thermoacoustic engine consists of a heat source and a cordierite honeycomb stack which converts heat into acoustic energy. The heat pumping takes place within a thermoacoustic refrigerator. Guidance on the material selection, constraints and calculation of the geometrical configuration describing the device constitute the main contribution of this work
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- Authors: Alcock, A.C. , Tartibu, L.K. , Jen, T.C.
- Date: 2017
- Subjects: Design , Thermoacoustic refrigeration , TADTAR
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250780 , uj:26139 , Citation: Alcock, A.C., Tartibu, L.K. & Jen, T.C. 2017. Design and construction of a thermoacoustically driven thermoacoustic refrigerator.
- Description: Abstract: This work describes the design and construction of a standing wave Thermoacoustically Driven Thermoacoustic Refrigerator (TADTAR). The thermoacoustic cooler is proposed in this study as an alternative sustainable solution to current issues with vapor compression refrigerators, due to its environmentally friendlier attributes and its solar energy driven capabilities. However, one of the main hindrances to the expansion of this technology is its current lack of efficiency and performance closely related to the designing of the device. Hence, a model has been designed and constructed to perform an experimental investigation of the device’s performance at the University of Johannesburg. This model will mainly be used to investigate the dynamics of the TADTAR arrangement. The TADTAR consists of two thermoacoustic systems namely a thermoacoustic engine coupled to a thermoacoustic refrigerator. The thermoacoustic engine consists of a heat source and a cordierite honeycomb stack which converts heat into acoustic energy. The heat pumping takes place within a thermoacoustic refrigerator. Guidance on the material selection, constraints and calculation of the geometrical configuration describing the device constitute the main contribution of this work
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Development and performance evaluation of a standing-wave thermo-acoustic engine
- Spambo, S., Ngcukayitobi, M., Shamase, H., Gqibani, S., Tartibu, L.K.
- Authors: Spambo, S. , Ngcukayitobi, M. , Shamase, H. , Gqibani, S. , Tartibu, L.K.
- Date: 2019
- Subjects: Standing-wave , Thermo-acoustic engine , Sound
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/401854 , uj:33604 , Citation: Spambo, S. et al. Development and performance evaluation of a standing-wave thermo-acoustic engine.
- Description: Abstract: The current work describes the development, construction and experimental investigation of a simple Standing-Wave Thermo-Acoustic Engine (SWTAE). This work aims at providing additional clarity on the construction and the performance of simple SWTAEs. The proposed SWTAE will be used to drive a traveling wave thermo-acoustic refrigerator, through the generated sound wave and ultimately induce cooling. For experimental purposes, the heat supply used in this experimental study are electric cartridge heaters. This study provides clarity as far as the temperature supplied to the system is concerned. To characterize the acoustic power of the SWTAE, the onset temperature differences across the stack for the engine to start producing sound has been measured. Three different configurations have been investigated and general trends showing the relationship between the supply heat, the generated sound wave and the minimum temperature required to produce a sound wave have been obtained.
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- Authors: Spambo, S. , Ngcukayitobi, M. , Shamase, H. , Gqibani, S. , Tartibu, L.K.
- Date: 2019
- Subjects: Standing-wave , Thermo-acoustic engine , Sound
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/401854 , uj:33604 , Citation: Spambo, S. et al. Development and performance evaluation of a standing-wave thermo-acoustic engine.
- Description: Abstract: The current work describes the development, construction and experimental investigation of a simple Standing-Wave Thermo-Acoustic Engine (SWTAE). This work aims at providing additional clarity on the construction and the performance of simple SWTAEs. The proposed SWTAE will be used to drive a traveling wave thermo-acoustic refrigerator, through the generated sound wave and ultimately induce cooling. For experimental purposes, the heat supply used in this experimental study are electric cartridge heaters. This study provides clarity as far as the temperature supplied to the system is concerned. To characterize the acoustic power of the SWTAE, the onset temperature differences across the stack for the engine to start producing sound has been measured. Three different configurations have been investigated and general trends showing the relationship between the supply heat, the generated sound wave and the minimum temperature required to produce a sound wave have been obtained.
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Impact of ceramic substrates geometry on the performance of simple thermo-acoustic engines
- Authors: Tartibu, L.K.
- Date: 2017
- Subjects: Thermo-acoustic engine , Stack, , Thermal losses
- Language: English
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/365679 , http://hdl.handle.net/10210/250688 , uj:26129 , Citation: Tartibu, L.K. 2017. Impact of ceramic substrates geometry on the performance of simple thermo-acoustic engines.
- Description: Abstract: This work experimentally examines the influence of the stack geometry and position on the performance of thermo-acoustic engines (TAE). Twenty cordierite honeycomb ceramic stacks with square pores and five different lengths (7 mm, 13 mm, 17 mm, 22 mm and 25 mm) were considered. Measurements were taken at seven different locations of the stack hot ends from the pressure antinode (closed end), namely 52 mm, 72 mm, 92 mm,112 mm, 132 mm, 152 mm and 172 mm respectively. The temperature difference across the stack and radiated sound pressure level at steady state are considered indicators of the performance of the device. The results obtained with a simple standing wave thermo-acoustic engine used in this experiment reveals that the relationships between the length, the stack pores sizes and the input power are non-linear. In addition, the effect of the viscous resistance and the thermal losses were confirmed to be strong enough when the input heating power is low.
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- Authors: Tartibu, L.K.
- Date: 2017
- Subjects: Thermo-acoustic engine , Stack, , Thermal losses
- Language: English
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/365679 , http://hdl.handle.net/10210/250688 , uj:26129 , Citation: Tartibu, L.K. 2017. Impact of ceramic substrates geometry on the performance of simple thermo-acoustic engines.
- Description: Abstract: This work experimentally examines the influence of the stack geometry and position on the performance of thermo-acoustic engines (TAE). Twenty cordierite honeycomb ceramic stacks with square pores and five different lengths (7 mm, 13 mm, 17 mm, 22 mm and 25 mm) were considered. Measurements were taken at seven different locations of the stack hot ends from the pressure antinode (closed end), namely 52 mm, 72 mm, 92 mm,112 mm, 132 mm, 152 mm and 172 mm respectively. The temperature difference across the stack and radiated sound pressure level at steady state are considered indicators of the performance of the device. The results obtained with a simple standing wave thermo-acoustic engine used in this experiment reveals that the relationships between the length, the stack pores sizes and the input power are non-linear. In addition, the effect of the viscous resistance and the thermal losses were confirmed to be strong enough when the input heating power is low.
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Lexicographic multi-objective optimization of thermoacoustic refrigerator’s stack
- Tartibu, L.K., Sun, B., Kaunda, M.A.E.
- Authors: Tartibu, L.K. , Sun, B. , Kaunda, M.A.E.
- Date: 2015
- Subjects: Thermoacoustic , Stack , Cooling Load , Coefficient of performance , Multi-objective optimization , GAMS
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17624 , uj:15907 , ISSN: 0947-7411 , Citation: Tartibu, L.K., Sun, B. & Kaunda M.A.E. 2015. Lexicographic multi-objective optimisation of thermoacoustic refrigerator’s stack. Journal of Heat and Mass Transfer. 51(5): 649-660. DOI: 10.1007/s00231-014-1440-z. , DOI: 10.1007/s00231-014-1440-z
- Description: Abstract: This work develops a novel mathematical programming model to optimize the performance of a simple thermoacoustic refrigerator (TAR). This study aims to optimize the geometric parameters namely the stack position, the stack length, the blockage ratio and the plate spacing involved in designing TARs. System parameters and constraints that capture the underlying thermoacoustic dynamics have been used to define the models. The cooling load, the coefficient of performance and the acoustic power loss have been used to measure the performance of the device. The optimization task is formulated as a three-criterion nonlinear programming problem with discontinuous derivatives (DNLP). Since we optimize multiple objectives simultaneously, each objective component has been given a weighting factor to provide appropriate user-defined emphasis. A practical example is given to illustrate the approach. We have determined a design statement of a stack describing how the geometrical parameters describing would change if emphasis is given to one objective in particular. We also considered optimization of multiple objectives components simultaneously and identify global optimal solutions describing the stack geometry using a lexicographic multiobjective optimization scheme. Additionally, this approach illustrates the difference between a design for maximum cooling and best coefficient of performance of a simple TAR.
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- Authors: Tartibu, L.K. , Sun, B. , Kaunda, M.A.E.
- Date: 2015
- Subjects: Thermoacoustic , Stack , Cooling Load , Coefficient of performance , Multi-objective optimization , GAMS
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17624 , uj:15907 , ISSN: 0947-7411 , Citation: Tartibu, L.K., Sun, B. & Kaunda M.A.E. 2015. Lexicographic multi-objective optimisation of thermoacoustic refrigerator’s stack. Journal of Heat and Mass Transfer. 51(5): 649-660. DOI: 10.1007/s00231-014-1440-z. , DOI: 10.1007/s00231-014-1440-z
- Description: Abstract: This work develops a novel mathematical programming model to optimize the performance of a simple thermoacoustic refrigerator (TAR). This study aims to optimize the geometric parameters namely the stack position, the stack length, the blockage ratio and the plate spacing involved in designing TARs. System parameters and constraints that capture the underlying thermoacoustic dynamics have been used to define the models. The cooling load, the coefficient of performance and the acoustic power loss have been used to measure the performance of the device. The optimization task is formulated as a three-criterion nonlinear programming problem with discontinuous derivatives (DNLP). Since we optimize multiple objectives simultaneously, each objective component has been given a weighting factor to provide appropriate user-defined emphasis. A practical example is given to illustrate the approach. We have determined a design statement of a stack describing how the geometrical parameters describing would change if emphasis is given to one objective in particular. We also considered optimization of multiple objectives components simultaneously and identify global optimal solutions describing the stack geometry using a lexicographic multiobjective optimization scheme. Additionally, this approach illustrates the difference between a design for maximum cooling and best coefficient of performance of a simple TAR.
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Maximum cooling and maximum efficiency of thermoacoustic refrigerators
- Authors: Tartibu, L.K.
- Date: 2016
- Subjects: Thermoacoustic refrigerator, , Stack , Cooling load
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/92045 , uj:20178 , Citation: Tartibu, L.K. 2016. Maximum cooling and maximum efficiency of thermoacoustic refrigerators.
- Description: Abstract: This work provides valid experimental evidence on the difference between design for maximum cooling and maximum efficiency for thermoacoustic refrigerators. In addition, the influence of the geometry of the honeycomb ceramic stack on the performance of thermoacoustic refrigerators is presented as it affects the cooling power. Sixteen cordierite honeycomb ceramic stacks with square cross sections having four different lengths of 26 mm, 48 mm, 70 mm and 100 mm are considered. Measurements are taken at six different locations of the stack hot ends from the pressure antinode, namely 100 mm, 200 mm, 300 mm, 400 mm, 500 mm and 600 mm respectively. Measurement of temperature difference across the stack ends at steady state for different stack geometries are used to compute the cooling load and the coefficient of performance. The results obtained with atmospheric air showed that there is a distinct optimum depending on the design goal.
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- Authors: Tartibu, L.K.
- Date: 2016
- Subjects: Thermoacoustic refrigerator, , Stack , Cooling load
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/92045 , uj:20178 , Citation: Tartibu, L.K. 2016. Maximum cooling and maximum efficiency of thermoacoustic refrigerators.
- Description: Abstract: This work provides valid experimental evidence on the difference between design for maximum cooling and maximum efficiency for thermoacoustic refrigerators. In addition, the influence of the geometry of the honeycomb ceramic stack on the performance of thermoacoustic refrigerators is presented as it affects the cooling power. Sixteen cordierite honeycomb ceramic stacks with square cross sections having four different lengths of 26 mm, 48 mm, 70 mm and 100 mm are considered. Measurements are taken at six different locations of the stack hot ends from the pressure antinode, namely 100 mm, 200 mm, 300 mm, 400 mm, 500 mm and 600 mm respectively. Measurement of temperature difference across the stack ends at steady state for different stack geometries are used to compute the cooling load and the coefficient of performance. The results obtained with atmospheric air showed that there is a distinct optimum depending on the design goal.
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Maximum cooling and maximum efficiency of thermoacoustic refrigerators
- Authors: Tartibu, L.K.
- Date: 2015
- Subjects: Thermoacoustic refrigerator , Stack , Cooling Load , Coefficient of performance
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17735 , uj:15918 , ISSN: 0947-7411 , Citation: Tartibu, L.K. 2015. Maximum cooling and maximum efficiency of thermoacoustic refrigerators. Journal of Heat and Mass Transfer, 51(7): 901-1050. DOI: 10.1007/s00231-015-1599-y. , DOI: 10.1007/s00231-015-1599-y
- Description: Abstract: This work provides valid experimental evidence on the difference between design for maximum cooling and maximum efficiency for thermoacoustic refrigerators. In addition, the influence of the geometry of the honeycomb ceramic stack on the performance of thermoacoustic refrigerators is presented as it affects the cooling power. Sixteen cordierite honeycomb ceramic stacks with square cross sections having four different lengths of 26 mm, 48 mm, 70 mm and 100 mm are considered. Measurements are taken at six different locations of the stack hot ends from the pressure antinode, namely 100 mm, 200 mm, 300 mm, 400 mm, 500 mm and 600 mm respectively. Measurement of temperature difference across the stack ends at steady state for different stack geometries are used to compute the cooling load and the coefficient of performance. The results obtained with atmospheric air showed that there is a distinct optimum depending on the design goal.
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- Authors: Tartibu, L.K.
- Date: 2015
- Subjects: Thermoacoustic refrigerator , Stack , Cooling Load , Coefficient of performance
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17735 , uj:15918 , ISSN: 0947-7411 , Citation: Tartibu, L.K. 2015. Maximum cooling and maximum efficiency of thermoacoustic refrigerators. Journal of Heat and Mass Transfer, 51(7): 901-1050. DOI: 10.1007/s00231-015-1599-y. , DOI: 10.1007/s00231-015-1599-y
- Description: Abstract: This work provides valid experimental evidence on the difference between design for maximum cooling and maximum efficiency for thermoacoustic refrigerators. In addition, the influence of the geometry of the honeycomb ceramic stack on the performance of thermoacoustic refrigerators is presented as it affects the cooling power. Sixteen cordierite honeycomb ceramic stacks with square cross sections having four different lengths of 26 mm, 48 mm, 70 mm and 100 mm are considered. Measurements are taken at six different locations of the stack hot ends from the pressure antinode, namely 100 mm, 200 mm, 300 mm, 400 mm, 500 mm and 600 mm respectively. Measurement of temperature difference across the stack ends at steady state for different stack geometries are used to compute the cooling load and the coefficient of performance. The results obtained with atmospheric air showed that there is a distinct optimum depending on the design goal.
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Modal testing of a simplified wind turbine blade
- Tartibu, L.K., Kilfoil, M., Van der Merwe, A.J.
- Authors: Tartibu, L.K. , Kilfoil, M. , Van der Merwe, A.J.
- Date: 2012
- Subjects: Model testing , Wind turbines , Natural frequencies , Finite element analysis , Euler Bernoulli beam
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/16573 , uj:15785 , ISSN: 2231-1963 , Citation: Tartibu K., Kilfoil M. & Van der Merwe, A.J. 2012. Modal testing of a simplified wind turbine blade. International Journal of Advances in engineering and Technology, 4(1):649–660.
- Description: Abstract: This paper examines the modal analysis techniques applied in experiments using a uniform and a stepped beam. These simplified shapes are representative of the a wind turbine blade. Natural frequencies have been identified, therefore designers can ensure those natural frequencies will not be close to the frequency of the main excitation forces (1P or NbP with Nb being the number of rotor blades) in order to avoid resonance. The turbine blade is approximated by a cantilever, therefore, it is fully constrained where attached to a turbine shaft/hub. Flap-wise, edge-wise and torsional natural frequencies are calculated. The results found have been compared to numerical results and the exact solution of an Euler-Bernoulli beam. Concurrence is found for the frequency range of interest. Although, some discrepancies exist at higher frequencies (above 500 Hz), finite element analysis proves to be reliable for calculating natural frequencies.
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- Authors: Tartibu, L.K. , Kilfoil, M. , Van der Merwe, A.J.
- Date: 2012
- Subjects: Model testing , Wind turbines , Natural frequencies , Finite element analysis , Euler Bernoulli beam
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/16573 , uj:15785 , ISSN: 2231-1963 , Citation: Tartibu K., Kilfoil M. & Van der Merwe, A.J. 2012. Modal testing of a simplified wind turbine blade. International Journal of Advances in engineering and Technology, 4(1):649–660.
- Description: Abstract: This paper examines the modal analysis techniques applied in experiments using a uniform and a stepped beam. These simplified shapes are representative of the a wind turbine blade. Natural frequencies have been identified, therefore designers can ensure those natural frequencies will not be close to the frequency of the main excitation forces (1P or NbP with Nb being the number of rotor blades) in order to avoid resonance. The turbine blade is approximated by a cantilever, therefore, it is fully constrained where attached to a turbine shaft/hub. Flap-wise, edge-wise and torsional natural frequencies are calculated. The results found have been compared to numerical results and the exact solution of an Euler-Bernoulli beam. Concurrence is found for the frequency range of interest. Although, some discrepancies exist at higher frequencies (above 500 Hz), finite element analysis proves to be reliable for calculating natural frequencies.
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Modelling of thermo-acoustic refrigerators using general algebraic modelling system
- Authors: Tartibu, L.K.
- Date: 2016
- Subjects: Thermo-acoustic refrigerator , Optimisation , Modelling
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217038 , uj:21591 , Citation: Tartibu, L.K. 2016. Modelling of thermo-acoustic refrigerators using general algebraic modelling system.
- Description: Abstract: While thermo-acoustic refrigeration is new among emerging technology, it shows strong potential towards the development of sustainable and renewable energy systems by utilising a sound wave to remove the heat. This work discusses a new mathematical programming approach that provides fast initial engineering estimates to initial design calculations, describing the optimal geometry of thermo-acoustic refrigerators. Three different criteria describing their performances were taken into account: maximum cooling, best coefficient of performance and acoustic power loss. As the stack has been identified as the heart of the device where heat transfer takes place, this new approach aims to optimise its geometrical parameters: namely, the stack position, the stack length, the blockage ratio and the stack pore sizes. Hence, the optimisation task is formulated as a three-criterion nonlinear programming problem with discontinuous derivatives. This approach was implemented in the General Algebraic Modelling Systems. The unique characteristic of this research is the computation of all efficient optimal solutions, allowing the decision maker to identify the most efficient solution. The proposed modelling approach was investigated experimentally to evaluate its ability to predict the best parameters describing the geometry of the stack. Similar trends were obtained to support the use of the proposed approach in the design of thermo-acoustic refrigerators.
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- Authors: Tartibu, L.K.
- Date: 2016
- Subjects: Thermo-acoustic refrigerator , Optimisation , Modelling
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217038 , uj:21591 , Citation: Tartibu, L.K. 2016. Modelling of thermo-acoustic refrigerators using general algebraic modelling system.
- Description: Abstract: While thermo-acoustic refrigeration is new among emerging technology, it shows strong potential towards the development of sustainable and renewable energy systems by utilising a sound wave to remove the heat. This work discusses a new mathematical programming approach that provides fast initial engineering estimates to initial design calculations, describing the optimal geometry of thermo-acoustic refrigerators. Three different criteria describing their performances were taken into account: maximum cooling, best coefficient of performance and acoustic power loss. As the stack has been identified as the heart of the device where heat transfer takes place, this new approach aims to optimise its geometrical parameters: namely, the stack position, the stack length, the blockage ratio and the stack pore sizes. Hence, the optimisation task is formulated as a three-criterion nonlinear programming problem with discontinuous derivatives. This approach was implemented in the General Algebraic Modelling Systems. The unique characteristic of this research is the computation of all efficient optimal solutions, allowing the decision maker to identify the most efficient solution. The proposed modelling approach was investigated experimentally to evaluate its ability to predict the best parameters describing the geometry of the stack. Similar trends were obtained to support the use of the proposed approach in the design of thermo-acoustic refrigerators.
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Multi-objective optimization of the stack of a thermoacoustic engine using GAMS
- Tartibu, L.K., Sun, B., Kaunda, M.A.E.
- Authors: Tartibu, L.K. , Sun, B. , Kaunda, M.A.E.
- Date: 2014
- Subjects: Thermoacoustics engine , Multi-objective optimization , GAMS , Mathematical programming
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17579 , uj:15902 , Citation: Tartibu, L.K., Sun, B. & Kaunda M.A.E. 2015. Multi-objective optimisation of a thermoacoustic regenerator using GAMS. Journal of Applied Soft Computing, 28: 30–43.
- Description: Abstract: tThis work illustrates the use of a multi-objective optimization approach to model and optimize theperformance of a simple thermoacoustic engine. System parameters and constraints that capture theunderlying thermoacoustic dynamics have been used to define the model. Work output, viscous loss,conductive heat loss, convective heat loss and radiative heat loss have been used to measure the per-formance of the engine. The optimization task is formulated as a five-criterion mixed-integer non-linearprogramming problem. Since we optimize multiple objectives simultaneously, each objective componenthas been given a weighting factor to provide appropriate user-defined emphasis. A practical example isgiven to illustrate the approach. We have determined a design statement of a stack describing how thedesign would change if emphasis is given to one objective in particular. We also considered optimiza-tion of multiple objectives components simultaneously and identify global optimal solutions describingthe stack geometry using the augmented ε-constraint method. This approach has been implemented inGAMS (General Algebraic Modelling System).
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- Authors: Tartibu, L.K. , Sun, B. , Kaunda, M.A.E.
- Date: 2014
- Subjects: Thermoacoustics engine , Multi-objective optimization , GAMS , Mathematical programming
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17579 , uj:15902 , Citation: Tartibu, L.K., Sun, B. & Kaunda M.A.E. 2015. Multi-objective optimisation of a thermoacoustic regenerator using GAMS. Journal of Applied Soft Computing, 28: 30–43.
- Description: Abstract: tThis work illustrates the use of a multi-objective optimization approach to model and optimize theperformance of a simple thermoacoustic engine. System parameters and constraints that capture theunderlying thermoacoustic dynamics have been used to define the model. Work output, viscous loss,conductive heat loss, convective heat loss and radiative heat loss have been used to measure the per-formance of the engine. The optimization task is formulated as a five-criterion mixed-integer non-linearprogramming problem. Since we optimize multiple objectives simultaneously, each objective componenthas been given a weighting factor to provide appropriate user-defined emphasis. A practical example isgiven to illustrate the approach. We have determined a design statement of a stack describing how thedesign would change if emphasis is given to one objective in particular. We also considered optimiza-tion of multiple objectives components simultaneously and identify global optimal solutions describingthe stack geometry using the augmented ε-constraint method. This approach has been implemented inGAMS (General Algebraic Modelling System).
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Numerical analysis of the flow pathlines in thermo-acoustic couples
- Authors: Tartibu, L.K. , Kunene, T.
- Date: 2019
- Subjects: Thermo-acoustic , Heat transfer , Stack
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/401870 , uj:33606 , Citation: Tartibu, L.K. & Kunene, T. 2019. Numerical analysis of the flow pathlines in thermo-acoustic couples.
- Description: Abstract: Thermo-acoustic systems use a high amplitude sound-wave for refrigeration or electricity generation without the drawbacks of expensive construction, adverse environmental impact or high maintenance cost. The effective conversion of energy occurs within the “stack” considered as the heart of the system. The time-averaged rate of heat transfer across the edges of the stack is a good indicator of an effective performance. Hence, studying the effect of the geometry of the stack edges together with their locations is useful. Furthermore, current manufacturing practices make it possible to develop diverse stack edges, resulting in an improved efficiency of the heat transfer. For effective modelling of the heat transfer rate, a second-order, double-precision discretization of state variables and a laminar viscous model was used. A numerical model was developed using the commercial code FLUENT. The evolution of the flow vortices at different drive ratio was analyzed. Two edges shapes were considered namely rectangular and rounded edges. Using numerical analysis, this study has pointed out that stack edge profiles has a significant effect on the overall performance of thermo-acoustic systems. Rounding the stack edge profile appears to be beneficial for the system performance. This study point out the link between the non-linearity observed in thermo-acoustic systems, the flow streaming and the mean vorticity at the stack edges.
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- Authors: Tartibu, L.K. , Kunene, T.
- Date: 2019
- Subjects: Thermo-acoustic , Heat transfer , Stack
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/401870 , uj:33606 , Citation: Tartibu, L.K. & Kunene, T. 2019. Numerical analysis of the flow pathlines in thermo-acoustic couples.
- Description: Abstract: Thermo-acoustic systems use a high amplitude sound-wave for refrigeration or electricity generation without the drawbacks of expensive construction, adverse environmental impact or high maintenance cost. The effective conversion of energy occurs within the “stack” considered as the heart of the system. The time-averaged rate of heat transfer across the edges of the stack is a good indicator of an effective performance. Hence, studying the effect of the geometry of the stack edges together with their locations is useful. Furthermore, current manufacturing practices make it possible to develop diverse stack edges, resulting in an improved efficiency of the heat transfer. For effective modelling of the heat transfer rate, a second-order, double-precision discretization of state variables and a laminar viscous model was used. A numerical model was developed using the commercial code FLUENT. The evolution of the flow vortices at different drive ratio was analyzed. Two edges shapes were considered namely rectangular and rounded edges. Using numerical analysis, this study has pointed out that stack edge profiles has a significant effect on the overall performance of thermo-acoustic systems. Rounding the stack edge profile appears to be beneficial for the system performance. This study point out the link between the non-linearity observed in thermo-acoustic systems, the flow streaming and the mean vorticity at the stack edges.
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Optimal design of a standing wave thermoacoustic refrigerator using GAMS
- Tartibu, L.K., Sun, B., Kaunda, M.A.E.
- Authors: Tartibu, L.K. , Sun, B. , Kaunda, M.A.E.
- Date: 2015
- Subjects: Thermoacoustic refrigerator , Coefficient of Performance , Cooling , Multi-objective optimization , GAMS
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/17707 , uj:15915 , Citation: Tartibu, L.K., Sun, B. & Kaunda M.A.E. 2015. Optimal design of a standing wave thermoacoustic refrigerator using GAMS. Procedia Computer Science, 62, 611-618. The 2015 International Conference on Soft Computing and Software Engineering, 5-6 March, 2015, University of California, Berkeley.
- Description: Abstract: This work proposes a multi-objective optimization approach to model and optimize small scale standing wave thermoacoustic refrigerator (TAR). This study aims to optimize the geometric variables namely the stack position, the stack length, the blockage ratio and the plate spacing involved in designing thermoacoustic refrigerators. Unlike most previous studies, these variables are considered interdependent. System parameters and constraints that capture the underlying thermoacoustic dynamics have been used to define the models. The cooling load, the coefficient of performance and the acoustic power loss have been used to measure the performance of the device. The optimization task is formulated as a three-criterion nonlinear programming problem with discontinuous derivatives (DNLP). A practical example considering three different gases is given to illustrate the approach. This approach has been implemented in the software GAMS (General Algebraic modelling System) and Pareto optimal solutions describing the most preferred geometry for maximum performance of the device are computed using the augmented -constraint method.
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- Authors: Tartibu, L.K. , Sun, B. , Kaunda, M.A.E.
- Date: 2015
- Subjects: Thermoacoustic refrigerator , Coefficient of Performance , Cooling , Multi-objective optimization , GAMS
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/17707 , uj:15915 , Citation: Tartibu, L.K., Sun, B. & Kaunda M.A.E. 2015. Optimal design of a standing wave thermoacoustic refrigerator using GAMS. Procedia Computer Science, 62, 611-618. The 2015 International Conference on Soft Computing and Software Engineering, 5-6 March, 2015, University of California, Berkeley.
- Description: Abstract: This work proposes a multi-objective optimization approach to model and optimize small scale standing wave thermoacoustic refrigerator (TAR). This study aims to optimize the geometric variables namely the stack position, the stack length, the blockage ratio and the plate spacing involved in designing thermoacoustic refrigerators. Unlike most previous studies, these variables are considered interdependent. System parameters and constraints that capture the underlying thermoacoustic dynamics have been used to define the models. The cooling load, the coefficient of performance and the acoustic power loss have been used to measure the performance of the device. The optimization task is formulated as a three-criterion nonlinear programming problem with discontinuous derivatives (DNLP). A practical example considering three different gases is given to illustrate the approach. This approach has been implemented in the software GAMS (General Algebraic modelling System) and Pareto optimal solutions describing the most preferred geometry for maximum performance of the device are computed using the augmented -constraint method.
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Optimal design study of thermoacoustic regenerator with lexicographic optimization method
- Tartibu, L.K., Sun, B., Kaunda, M.A.E.
- Authors: Tartibu, L.K. , Sun, B. , Kaunda, M.A.E.
- Date: 2015
- Subjects: Design , Implementing , Managing and practicing innovation , Optimization algorithms , Mechanical design , Modelling , Multi-objective/attribute decision-making , Design strategies
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17471 , uj:15887 , ISSN: 1726-0531 , Citation: Tartibu, L.K. Sun, B. & Kaunda, M.A.E. 2015. Optimal design study of thermoacoustic regenerator with lexicographic optimization method. Journal of Engineering, Design and Technology, 13(3): 499 – 519. , DOI: 10.1108/JEDT-09-2012-0039.
- Description: Abstract: Purpose – This paper aims to illustrate the use of the augmented epsilon-constraint method implemented in general algebraic modelling system (GAMS), aimed at optimizing the geometry of a thermoacoustic regenerator. Thermoacoustic heat engines provide a practical solution to the problem of heat management where heat can be pumped or spot cooling can be produced. However, the most inhibiting characteristic of thermoacoustic cooling is their current lack of efficiencies. Design/methodology/approach – Lexicographic optimization is presented as an alternative optimization technique to the common used weighting methods. This approach establishes a hierarchical order among all the optimization objectives instead of giving them a specific (and most of the time, arbitrary) weight. Findings – A practical example is given, in a hypothetical scenario, showing how the proposed optimization technique may help thermoacoustic regenerator designers to identify Pareto optimal solutions when dealing with geometric parameters. This study highlights the fact that the geometrical parameters are interdependent, which support the use of a multi-objective approach for optimization in thermoacoustic. Originality/value – The research output from this paper can be a valuable resource to support designers in building efficient thermoacoustic device. The research illustrates the use of a lexicographic optimization to provide more meaningful results describing the geometry of thermoacoustic regenerator. It applies the epsilon-constraint method (AUGMENCON) to solve a five-criteria mixed integer non-linear problem implemented in GAMS (GAM software).
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- Authors: Tartibu, L.K. , Sun, B. , Kaunda, M.A.E.
- Date: 2015
- Subjects: Design , Implementing , Managing and practicing innovation , Optimization algorithms , Mechanical design , Modelling , Multi-objective/attribute decision-making , Design strategies
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17471 , uj:15887 , ISSN: 1726-0531 , Citation: Tartibu, L.K. Sun, B. & Kaunda, M.A.E. 2015. Optimal design study of thermoacoustic regenerator with lexicographic optimization method. Journal of Engineering, Design and Technology, 13(3): 499 – 519. , DOI: 10.1108/JEDT-09-2012-0039.
- Description: Abstract: Purpose – This paper aims to illustrate the use of the augmented epsilon-constraint method implemented in general algebraic modelling system (GAMS), aimed at optimizing the geometry of a thermoacoustic regenerator. Thermoacoustic heat engines provide a practical solution to the problem of heat management where heat can be pumped or spot cooling can be produced. However, the most inhibiting characteristic of thermoacoustic cooling is their current lack of efficiencies. Design/methodology/approach – Lexicographic optimization is presented as an alternative optimization technique to the common used weighting methods. This approach establishes a hierarchical order among all the optimization objectives instead of giving them a specific (and most of the time, arbitrary) weight. Findings – A practical example is given, in a hypothetical scenario, showing how the proposed optimization technique may help thermoacoustic regenerator designers to identify Pareto optimal solutions when dealing with geometric parameters. This study highlights the fact that the geometrical parameters are interdependent, which support the use of a multi-objective approach for optimization in thermoacoustic. Originality/value – The research output from this paper can be a valuable resource to support designers in building efficient thermoacoustic device. The research illustrates the use of a lexicographic optimization to provide more meaningful results describing the geometry of thermoacoustic regenerator. It applies the epsilon-constraint method (AUGMENCON) to solve a five-criteria mixed integer non-linear problem implemented in GAMS (GAM software).
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Performance alteration of standing-wave thermoacoustically-driven engine through resonator length adjustment
- Balonji, S., Alcock, A.C., Tartibu, L.K., Jen, T.C
- Authors: Balonji, S. , Alcock, A.C. , Tartibu, L.K. , Jen, T.C
- Date: 2019
- Subjects: Thermo-acoustic , Sound-wave , DELTAEC
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/401878 , uj:33607 , Citation: Balonji, S. et al. 2019. Performance alteration of standing-wave thermoacoustically-driven engine through resonator length adjustment.
- Description: Abstract: The production of sound-wave in thermo-acoustic device is necessary to induce cooling or generate electricity. The magnitude of the sound-wave is normally proportional to the amount of heat provided to the device. The possibility to use waste heat in any locations can be enough to justify the use of thermo-acoustic technology for sustainable electricity generation or refrigeration. In this work, an adjustable thermoacoustically-driven engine has been developed using the Design Environment for Low-amplitude ThermoAcoustic Energy Conversion (DELTAEC). Many studies have highlighted the relationship between the geometry of the stack and the performance of the device. Unlike previous studies, the resonator of this thermoacoustically-driven device, made of two portions, was adjusted. The performance of the device has been analysed in order to evaluate the influence of the alteration of the resonator on the heat-to-sound conversion. Performance indicators like the acoustic power, the temperature difference across the stack and the frequency of the sound-wave have been studied. This work point out the possibility to regulate the performance of thermo-acoustic engine by adjusting the geometry of the resonator.
- Full Text:
- Authors: Balonji, S. , Alcock, A.C. , Tartibu, L.K. , Jen, T.C
- Date: 2019
- Subjects: Thermo-acoustic , Sound-wave , DELTAEC
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/401878 , uj:33607 , Citation: Balonji, S. et al. 2019. Performance alteration of standing-wave thermoacoustically-driven engine through resonator length adjustment.
- Description: Abstract: The production of sound-wave in thermo-acoustic device is necessary to induce cooling or generate electricity. The magnitude of the sound-wave is normally proportional to the amount of heat provided to the device. The possibility to use waste heat in any locations can be enough to justify the use of thermo-acoustic technology for sustainable electricity generation or refrigeration. In this work, an adjustable thermoacoustically-driven engine has been developed using the Design Environment for Low-amplitude ThermoAcoustic Energy Conversion (DELTAEC). Many studies have highlighted the relationship between the geometry of the stack and the performance of the device. Unlike previous studies, the resonator of this thermoacoustically-driven device, made of two portions, was adjusted. The performance of the device has been analysed in order to evaluate the influence of the alteration of the resonator on the heat-to-sound conversion. Performance indicators like the acoustic power, the temperature difference across the stack and the frequency of the sound-wave have been studied. This work point out the possibility to regulate the performance of thermo-acoustic engine by adjusting the geometry of the resonator.
- Full Text:
Potential energy savings from cool roofs in South Africa
- Tartibu, L.K., Bakaya-Kyahurwa, E.
- Authors: Tartibu, L.K. , Bakaya-Kyahurwa, E.
- Date: 2017
- Subjects: Cool roof , Energy saving , Cooling saving
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250719 , uj:26133 , Citation: Tartibu, L.K. & Bakaya-Kyahurwa, E. 2017. Potential energy savings from cool roofs in South Africa.
- Description: Abstract: Cool roofs are beneficial for most buildings almost everywhere in the world. They are described as an inexpensive method in order to improve the comfort level in buildings in mild and hot climate or save energy. However, their cost-effectiveness can vary significantly, depending on climate and local factors. Therefore, the use of simulations with local conditions can provide the clarity required in order to deploy cool roofs in a particular location. This paper presents an estimation of the potential energy savings resulting from the use of cool roofs for different climatological conditions within South Africa. Several cities have been selected across South Africa and climatological data have been obtained from the NASA Atmospheric Science Data Center. The DOE Cool Roof Calculator was adapted for the estimation of cooling and heating saving corresponding to specific type of roofs and climatological variables within these selected cities. The preliminary results strongly suggest that cool roofs yield positive potential savings in residences using electrical heating for most of the cities studied.
- Full Text:
- Authors: Tartibu, L.K. , Bakaya-Kyahurwa, E.
- Date: 2017
- Subjects: Cool roof , Energy saving , Cooling saving
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250719 , uj:26133 , Citation: Tartibu, L.K. & Bakaya-Kyahurwa, E. 2017. Potential energy savings from cool roofs in South Africa.
- Description: Abstract: Cool roofs are beneficial for most buildings almost everywhere in the world. They are described as an inexpensive method in order to improve the comfort level in buildings in mild and hot climate or save energy. However, their cost-effectiveness can vary significantly, depending on climate and local factors. Therefore, the use of simulations with local conditions can provide the clarity required in order to deploy cool roofs in a particular location. This paper presents an estimation of the potential energy savings resulting from the use of cool roofs for different climatological conditions within South Africa. Several cities have been selected across South Africa and climatological data have been obtained from the NASA Atmospheric Science Data Center. The DOE Cool Roof Calculator was adapted for the estimation of cooling and heating saving corresponding to specific type of roofs and climatological variables within these selected cities. The preliminary results strongly suggest that cool roofs yield positive potential savings in residences using electrical heating for most of the cities studied.
- Full Text:
Thermal losses considerations in thermo-acoustic engine design
- Authors: Tartibu, L.K.
- Date: 2016
- Subjects: Thermo-acoustic engine , Modelling , Multi-objective optimization
- Language: English
- Type: Conference proceedings
- Identifier: http://ujcontent.uj.ac.za8080/10210/385373 , http://hdl.handle.net/10210/217031 , uj:21588 , Citation: Tartibu, L.K. 2016. Thermal losses considerations in thermo-acoustic engine design.
- Description: Abstract: Thermo-acoustic cooling as an environmentally friendly refrigeration system is one of the research areas being pursued. Although not commercially available and simple to fabricate, the designing of thermo-acoustic coolers involves significant technical challenges. Many fundamental issues related to the thermo-acoustic effects and the associated heat transfer must be addressed. The most inhibiting characteristic of current thermo-acoustic cooling devices is the lack of efficiency. The stack has been identified as the heart of the device where the heat transfer takes place. Improving its performance will make thermo-acoustic technology more attractive. Most of the existing efforts have not taken thermal losses to the surroundings into account in the derivation of the models. Five different parameters describing the stack geometry and the angular frequency of the standing wave are considered. This work explores the use of a multi-objective optimization approach to model and to optimize the performance of a simple thermo-acoustic engine. The present study highlights the importance of thermal losses in the modelling of small-scale thermo-acoustic engines using a multi-objective approach. The unique characteristic of this research is the computing of all efficient optimal solutions describing the best geometrical configuration of thermo-acoustic engines.
- Full Text:
- Authors: Tartibu, L.K.
- Date: 2016
- Subjects: Thermo-acoustic engine , Modelling , Multi-objective optimization
- Language: English
- Type: Conference proceedings
- Identifier: http://ujcontent.uj.ac.za8080/10210/385373 , http://hdl.handle.net/10210/217031 , uj:21588 , Citation: Tartibu, L.K. 2016. Thermal losses considerations in thermo-acoustic engine design.
- Description: Abstract: Thermo-acoustic cooling as an environmentally friendly refrigeration system is one of the research areas being pursued. Although not commercially available and simple to fabricate, the designing of thermo-acoustic coolers involves significant technical challenges. Many fundamental issues related to the thermo-acoustic effects and the associated heat transfer must be addressed. The most inhibiting characteristic of current thermo-acoustic cooling devices is the lack of efficiency. The stack has been identified as the heart of the device where the heat transfer takes place. Improving its performance will make thermo-acoustic technology more attractive. Most of the existing efforts have not taken thermal losses to the surroundings into account in the derivation of the models. Five different parameters describing the stack geometry and the angular frequency of the standing wave are considered. This work explores the use of a multi-objective optimization approach to model and to optimize the performance of a simple thermo-acoustic engine. The present study highlights the importance of thermal losses in the modelling of small-scale thermo-acoustic engines using a multi-objective approach. The unique characteristic of this research is the computing of all efficient optimal solutions describing the best geometrical configuration of thermo-acoustic engines.
- Full Text:
Vibration analysis of a variable length blade wind turbine
- Tartibu, L.K., Kilfoil, M., Van der Merwe, A.J.
- Authors: Tartibu, L.K. , Kilfoil, M. , Van der Merwe, A.J.
- Date: 2012
- Subjects: Variable length blade , Natural frequencies , Vibration , Finite element analysis , Wind turbine
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/16229 , uj:15753 , ISSN: 2231-1963 , Citation: Tartibu K., Kilfoil M., Van Der Merwe, A. J. 2012. Vibration analysis of a variable blade length wind turbine. International Journal of Advances in engineering and Technology, 4(1): 630–639.
- Description: Abstract: In this paper, Flap-wise, edge-wise and torsional natural frequencies of a variable length blade have been identified. Therefore designers can ensure that natural frequencies will not be close to the frequency of the main excitation forces in order to avoid resonance. The fixed portion and moveable portion of the variable length blade are approximated respectively by a hollow and a solid beam which can be slid in and out. Ten different configurations of the variable length blade, representing ten different positions of the moveable portion are investigated. A MATLAB program was developed to predict natural frequencies. Similarly three-dimensional models of the variable length blade have been developed in the finite element program Unigraphics NX5. Concurrence between MATLAB and Unigraphics NX5 results has been found for the frequency range of interest. This means that an effective method to compute natural frequencies of a variable length blade was developed.
- Full Text:
- Authors: Tartibu, L.K. , Kilfoil, M. , Van der Merwe, A.J.
- Date: 2012
- Subjects: Variable length blade , Natural frequencies , Vibration , Finite element analysis , Wind turbine
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/16229 , uj:15753 , ISSN: 2231-1963 , Citation: Tartibu K., Kilfoil M., Van Der Merwe, A. J. 2012. Vibration analysis of a variable blade length wind turbine. International Journal of Advances in engineering and Technology, 4(1): 630–639.
- Description: Abstract: In this paper, Flap-wise, edge-wise and torsional natural frequencies of a variable length blade have been identified. Therefore designers can ensure that natural frequencies will not be close to the frequency of the main excitation forces in order to avoid resonance. The fixed portion and moveable portion of the variable length blade are approximated respectively by a hollow and a solid beam which can be slid in and out. Ten different configurations of the variable length blade, representing ten different positions of the moveable portion are investigated. A MATLAB program was developed to predict natural frequencies. Similarly three-dimensional models of the variable length blade have been developed in the finite element program Unigraphics NX5. Concurrence between MATLAB and Unigraphics NX5 results has been found for the frequency range of interest. This means that an effective method to compute natural frequencies of a variable length blade was developed.
- Full Text:
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