Feasibility and effectiveness of heat pipe cooling in end milling operations : thermal, structural static, and dynamic analyses : a new approach
- Zhu, Lin, Jen, Tien-Chien, Yen, Yi-Hsin, Kong, Xiao-Ling
- Authors: Zhu, Lin , Jen, Tien-Chien , Yen, Yi-Hsin , Kong, Xiao-Ling
- Date: 2011
- Subjects: Heat pipes , Heat pipe cooling
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/384755 , uj:5288 , http://hdl.handle.net/10210/14957
- Description: In this paper, the feasibility and effectiveness of heat pipe cooling in end milling operations are investigated. A new embedded heat pipe technology was utilized to remove the heat generated at the tool-interface in end milling processes. Numerical studies involved four cases, including dry milling, fluid cooling, heat pipe cooling, and heat pipe cooling with cutting fluid supplied. The thermal, structural static, and dynamic characteristics of the endmill were investigated using a numerical calculation with fast finite element plus solvers based on explicit finite element analysis software. The results demonstrate that the heat pipe end-mill is most feasible and effective in the actual end milling processes
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- Authors: Zhu, Lin , Jen, Tien-Chien , Yen, Yi-Hsin , Kong, Xiao-Ling
- Date: 2011
- Subjects: Heat pipes , Heat pipe cooling
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/384755 , uj:5288 , http://hdl.handle.net/10210/14957
- Description: In this paper, the feasibility and effectiveness of heat pipe cooling in end milling operations are investigated. A new embedded heat pipe technology was utilized to remove the heat generated at the tool-interface in end milling processes. Numerical studies involved four cases, including dry milling, fluid cooling, heat pipe cooling, and heat pipe cooling with cutting fluid supplied. The thermal, structural static, and dynamic characteristics of the endmill were investigated using a numerical calculation with fast finite element plus solvers based on explicit finite element analysis software. The results demonstrate that the heat pipe end-mill is most feasible and effective in the actual end milling processes
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Experimental analyses to investigate the feasibility and effectiveness in using heat pipe-embedded drills
- Zhu, Lin, Jen, Tien-Chien, Yin, Cheng-Long, Kong, Xiao-Ling, Yen, Yi-Hsin
- Authors: Zhu, Lin , Jen, Tien-Chien , Yin, Cheng-Long , Kong, Xiao-Ling , Yen, Yi-Hsin
- Date: 2012
- Subjects: Heat pipe cooling , Drilling , Heat pipes
- Type: Article
- Identifier: uj:5289 , http://hdl.handle.net/10210/14958
- Description: This paper presents an experimental investigation to verify the feasibility and effectiveness of heat pipe cooling in drilling operations. The basic idea is to insert a heat pipe at the center of the drill tool with the evaporator close to the drill tip and the condenser at the end of the drill. Consequently, the heat generated at the tool–chip interface can be removed by convection heat transfer. Experimental studies were involved in three cases, including solid drill without coolant, solid drill with coolant, and heat pipe drill. Drilling tests were conducted on a CNC machining center with full immersion cutting. The cast iron square block was used as the workpiece, and the high-speed steel was chosen for the drill tool material. Flank wear is considered as the criterion for tool failure, and the wear was measured using a Hisomet II Toolmaker’s microscope. The tests were conducted until the drill was rejected when an average flank wear greater than 0.10 mm was recorded. The results demonstrate that using a heat pipe in the drilling process can effectively perform thermal management comparable to the flooding coolant cooling used pervasively in the manufacturing industry, extending the tool life of the drill.
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- Authors: Zhu, Lin , Jen, Tien-Chien , Yin, Cheng-Long , Kong, Xiao-Ling , Yen, Yi-Hsin
- Date: 2012
- Subjects: Heat pipe cooling , Drilling , Heat pipes
- Type: Article
- Identifier: uj:5289 , http://hdl.handle.net/10210/14958
- Description: This paper presents an experimental investigation to verify the feasibility and effectiveness of heat pipe cooling in drilling operations. The basic idea is to insert a heat pipe at the center of the drill tool with the evaporator close to the drill tip and the condenser at the end of the drill. Consequently, the heat generated at the tool–chip interface can be removed by convection heat transfer. Experimental studies were involved in three cases, including solid drill without coolant, solid drill with coolant, and heat pipe drill. Drilling tests were conducted on a CNC machining center with full immersion cutting. The cast iron square block was used as the workpiece, and the high-speed steel was chosen for the drill tool material. Flank wear is considered as the criterion for tool failure, and the wear was measured using a Hisomet II Toolmaker’s microscope. The tests were conducted until the drill was rejected when an average flank wear greater than 0.10 mm was recorded. The results demonstrate that using a heat pipe in the drilling process can effectively perform thermal management comparable to the flooding coolant cooling used pervasively in the manufacturing industry, extending the tool life of the drill.
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Transient heat transfer analysis on a heat pipe with experimental validation
- Gutierrez, Gustavo, Catano, Juan, Jen, Tien-Chien, Liao, Quan
- Authors: Gutierrez, Gustavo , Catano, Juan , Jen, Tien-Chien , Liao, Quan
- Date: 2006
- Subjects: Numerical analysis , Heat transfer , Heat pipes
- Type: Article
- Identifier: uj:5270 , http://hdl.handle.net/10210/14939
- Description: In this study, a transient analysis of the performance of a heat pipe with a wick structure is performed. A complete formulation of the equation governing the operation of a heat pipe during transient conditions are presented and discussed. For the vapor flow, the conventional Navier-Stokes equations are used. For the liquid flow in the wick structure, which is modeled as a porous media, volume averaged Navier-Stokes equations are adopted. The energy equation is solved for the solid wall and wick structure of the heat pipe. The energy and momentum equations are coupled through the heat flux at the liquid-vapor interface that defines the suction and blowing velocities for the liquid and vapor flow. The evolution of the vaporliquid interface temperature is coupled through the heat flux at this interface that defines the mass flux to the vapor and the new saturation conditions to maintain a fully saturated vapor at all time. A control volume approach is used in the development of the numerical scheme. A parametric study is conducted to study the effect of different parameters that affect the thermal performance of the heat pipe. And experimental setup is developed and numerical res ults are validated with experimental data. The results of this study will be useful for the heat pipe design and implementation in processes that are essentially transient.
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- Authors: Gutierrez, Gustavo , Catano, Juan , Jen, Tien-Chien , Liao, Quan
- Date: 2006
- Subjects: Numerical analysis , Heat transfer , Heat pipes
- Type: Article
- Identifier: uj:5270 , http://hdl.handle.net/10210/14939
- Description: In this study, a transient analysis of the performance of a heat pipe with a wick structure is performed. A complete formulation of the equation governing the operation of a heat pipe during transient conditions are presented and discussed. For the vapor flow, the conventional Navier-Stokes equations are used. For the liquid flow in the wick structure, which is modeled as a porous media, volume averaged Navier-Stokes equations are adopted. The energy equation is solved for the solid wall and wick structure of the heat pipe. The energy and momentum equations are coupled through the heat flux at the liquid-vapor interface that defines the suction and blowing velocities for the liquid and vapor flow. The evolution of the vaporliquid interface temperature is coupled through the heat flux at this interface that defines the mass flux to the vapor and the new saturation conditions to maintain a fully saturated vapor at all time. A control volume approach is used in the development of the numerical scheme. A parametric study is conducted to study the effect of different parameters that affect the thermal performance of the heat pipe. And experimental setup is developed and numerical res ults are validated with experimental data. The results of this study will be useful for the heat pipe design and implementation in processes that are essentially transient.
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Integration of heat pipes into coaxial transformers utilizing coaxial conductors
- Authors: Pentz, D. C.
- Date: 2011
- Subjects: Heat pipes , Coaxial transformers , Coaxial conductors
- Language: English
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/379688 , http://hdl.handle.net/10210/17349 , uj:15875 , Pentz, D. C. 2011. Integration of heat pipes into coaxial transformers utilizing coaxial conductors.
- Description: Abstract: Magnetic component design has received much attention over the last few decades specifically with their application in high frequency power converters. Conventional indirect cooling methods for these components involve air and oil as transport mechanisms for the thermal energy. The insertion of thermally conductive layers and heat pipes into transformers has also been reported. This paper is aimed at the integration of heat pipes into coaxial transformers by using the conductors, already present for electrical functionality, as the heat pipe material. The concept is investigated experimentally by constructing a physical transformer.
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- Authors: Pentz, D. C.
- Date: 2011
- Subjects: Heat pipes , Coaxial transformers , Coaxial conductors
- Language: English
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/379688 , http://hdl.handle.net/10210/17349 , uj:15875 , Pentz, D. C. 2011. Integration of heat pipes into coaxial transformers utilizing coaxial conductors.
- Description: Abstract: Magnetic component design has received much attention over the last few decades specifically with their application in high frequency power converters. Conventional indirect cooling methods for these components involve air and oil as transport mechanisms for the thermal energy. The insertion of thermally conductive layers and heat pipes into transformers has also been reported. This paper is aimed at the integration of heat pipes into coaxial transformers by using the conductors, already present for electrical functionality, as the heat pipe material. The concept is investigated experimentally by constructing a physical transformer.
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Numerical analysis of the hydrodynamics of the flow in an axially rotating heat pipe
- Gutierrez, Gustavo, Jen, Tien-Chien
- Authors: Gutierrez, Gustavo , Jen, Tien-Chien
- Date: 2002
- Subjects: Hydrodynamics , Heat pipes , Drilling and boring
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/15688 , uj:15691 , Citation: Gutierrez, G. and Jen, T.-C. 2002. Numerical analysis of the hydrodynamics of the flow in an axially rotating heat pipe. Proceedings of IMECE2002 ASME International Mechanical Engineering Congress & Exposition, November 17-22, 2002, New Orleans, Louisiana, 5:1-13. , ISBN: 0-7918-3636-3
- Description: A numerical study is conducted on the vapor and liquid flow in a wick structure of an axially rotating heat pipe. For the vapor, the governing equations are the Navier-Stokes. For the liquid a space average of the Navier-Stokes equation is performed and a porous media model is introduced for the cross correlation that appears from the averaging process. A control volume approach on a staggered grid is used in the development of the computer program. Suction and blowing velocities are used as boundary conditions of the vapor and liquid, which are related to a local heat flux input in the evaporator section, and local heat flux output in the condenser section, respectively. The aim behind this study is the application of heat pipes in drilling applications. A triangular heat flux distribution is assumed in the evaporator due to the higher heat flux generated at the tip of the drill. A parametric study is conducted to analyze the effect of different parameters such as rotational speeds, saturation conditions, porosity, permeability and dimensions of the wick structure in the porous medium. These parameters significantly affect the pressure drop in the heat pipe and allow predicting failure conditions, which is critical in the design of heat pipes in drilling applications. The results of this study will be useful for the complete analysis of the heat pipe performance including the solution of the heat transfer on the solid wall as a conjugate problem.
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- Authors: Gutierrez, Gustavo , Jen, Tien-Chien
- Date: 2002
- Subjects: Hydrodynamics , Heat pipes , Drilling and boring
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/15688 , uj:15691 , Citation: Gutierrez, G. and Jen, T.-C. 2002. Numerical analysis of the hydrodynamics of the flow in an axially rotating heat pipe. Proceedings of IMECE2002 ASME International Mechanical Engineering Congress & Exposition, November 17-22, 2002, New Orleans, Louisiana, 5:1-13. , ISBN: 0-7918-3636-3
- Description: A numerical study is conducted on the vapor and liquid flow in a wick structure of an axially rotating heat pipe. For the vapor, the governing equations are the Navier-Stokes. For the liquid a space average of the Navier-Stokes equation is performed and a porous media model is introduced for the cross correlation that appears from the averaging process. A control volume approach on a staggered grid is used in the development of the computer program. Suction and blowing velocities are used as boundary conditions of the vapor and liquid, which are related to a local heat flux input in the evaporator section, and local heat flux output in the condenser section, respectively. The aim behind this study is the application of heat pipes in drilling applications. A triangular heat flux distribution is assumed in the evaporator due to the higher heat flux generated at the tip of the drill. A parametric study is conducted to analyze the effect of different parameters such as rotational speeds, saturation conditions, porosity, permeability and dimensions of the wick structure in the porous medium. These parameters significantly affect the pressure drop in the heat pipe and allow predicting failure conditions, which is critical in the design of heat pipes in drilling applications. The results of this study will be useful for the complete analysis of the heat pipe performance including the solution of the heat transfer on the solid wall as a conjugate problem.
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Heat transfer performance in 3D internally finned heat pipe
- Liao, Quan, Jen, Tien-Chien, Chen, Qing-hua, Li, Longjian, Cui, Wenzhi
- Authors: Liao, Quan , Jen, Tien-Chien , Chen, Qing-hua , Li, Longjian , Cui, Wenzhi
- Date: 2007
- Subjects: Heat pipes , Heat transfer , Finned tubes
- Type: Article
- Identifier: uj:5276 , http://hdl.handle.net/10210/14945
- Description: An experimental study of heat transfer performance in 3D internally finned steel-water heat pipe was carried out in this project. All the main parameters that can significantly influence the heat transfer performance of heat pipe, such as working temperature, heat flux, inclination angle, working fluid fill ratio (defined by the evaporation volume), have been examined. Within the experimental conditions (working temperature 40 C–95 C, heat flux 5.0 kw/m2–40 kw/m2, inclination angle 2–90 ), the evaporation and condensation heat transfer coefficients in 3D internally finned heat pipe are found to be increased by 50–100% and 100–200%, respectively, as compared to the smooth gravity-assisted heat pipe under the same conditions. Therefore, it is concluded that the special structures of 3D-fins on the inner wall can significantly reduce the internal thermal resistance of heat pipe and then greatly enhance its heat transfer performance.
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- Authors: Liao, Quan , Jen, Tien-Chien , Chen, Qing-hua , Li, Longjian , Cui, Wenzhi
- Date: 2007
- Subjects: Heat pipes , Heat transfer , Finned tubes
- Type: Article
- Identifier: uj:5276 , http://hdl.handle.net/10210/14945
- Description: An experimental study of heat transfer performance in 3D internally finned steel-water heat pipe was carried out in this project. All the main parameters that can significantly influence the heat transfer performance of heat pipe, such as working temperature, heat flux, inclination angle, working fluid fill ratio (defined by the evaporation volume), have been examined. Within the experimental conditions (working temperature 40 C–95 C, heat flux 5.0 kw/m2–40 kw/m2, inclination angle 2–90 ), the evaporation and condensation heat transfer coefficients in 3D internally finned heat pipe are found to be increased by 50–100% and 100–200%, respectively, as compared to the smooth gravity-assisted heat pipe under the same conditions. Therefore, it is concluded that the special structures of 3D-fins on the inner wall can significantly reduce the internal thermal resistance of heat pipe and then greatly enhance its heat transfer performance.
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Numerical analysis of the vapor flow in an axially rotating heat pipe in drilling processes
- Gutierrez, Gustavo, Jen, Tien-Chien
- Authors: Gutierrez, Gustavo , Jen, Tien-Chien
- Date: 2005
- Subjects: Vapor flow , Heat pipes , Axially rotating heat pipes
- Type: Article
- Identifier: uj:5259 , http://hdl.handle.net/10210/14928
- Description: Please refer to full text to view abstract
- Full Text:
- Authors: Gutierrez, Gustavo , Jen, Tien-Chien
- Date: 2005
- Subjects: Vapor flow , Heat pipes , Axially rotating heat pipes
- Type: Article
- Identifier: uj:5259 , http://hdl.handle.net/10210/14928
- Description: Please refer to full text to view abstract
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Thermal performance of heat pipe drill : experimental study
- Jen, Tien-Chien, Chen, Yau-Min, Gutierrez, Guatavo
- Authors: Jen, Tien-Chien , Chen, Yau-Min , Gutierrez, Guatavo
- Date: 2003
- Subjects: Drilling and boring , Heat pipes
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/15756 , uj:15696 , Citation: • Jen, T.-C., Chen Y-M., and Gutierrez, G., 2003. Thermal performance of heat pipe drill: experimental study.Proceedings of NHTC03: ASME Summer Heat Transfer conference,July 21-23,2003 Las Vegas, Nevada, USA, pages 1-7.
- Description: Abstract: An experimental study is performed in this paper to verify the concept of thermal management of using a heat pipe in the drilling process. The basic idea is to insert a heat pipe at the center of the drill tool with the evaporator located close to the drill tip, and condenser located at the end of the drill. In this way, heat accumulated in the drill tip can be transported to the remote section of the drill and remove it there to the tool holder, which attaches the drill. Temperatures at the drill tip as well as tool wear can be reduced significantly. In this paper, experimental investigations on a heat pipe drill for various heat flux inputs, inclination angles and rotating speeds are presented. The effect of contact resistance and tool holder (acting as heat sink) on heat pipe performance will also be demonstrated. The results presented in this paper may be used for important design and practical implementation considerations
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- Authors: Jen, Tien-Chien , Chen, Yau-Min , Gutierrez, Guatavo
- Date: 2003
- Subjects: Drilling and boring , Heat pipes
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/15756 , uj:15696 , Citation: • Jen, T.-C., Chen Y-M., and Gutierrez, G., 2003. Thermal performance of heat pipe drill: experimental study.Proceedings of NHTC03: ASME Summer Heat Transfer conference,July 21-23,2003 Las Vegas, Nevada, USA, pages 1-7.
- Description: Abstract: An experimental study is performed in this paper to verify the concept of thermal management of using a heat pipe in the drilling process. The basic idea is to insert a heat pipe at the center of the drill tool with the evaporator located close to the drill tip, and condenser located at the end of the drill. In this way, heat accumulated in the drill tip can be transported to the remote section of the drill and remove it there to the tool holder, which attaches the drill. Temperatures at the drill tip as well as tool wear can be reduced significantly. In this paper, experimental investigations on a heat pipe drill for various heat flux inputs, inclination angles and rotating speeds are presented. The effect of contact resistance and tool holder (acting as heat sink) on heat pipe performance will also be demonstrated. The results presented in this paper may be used for important design and practical implementation considerations
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