Abstract
M.Tech. (Mechanical Engineering)
The present study focuses on analysing the performance of a travelling-wave looped-tube thermo-acoustic engine. The introduction of thermo-acoustic theories has provided a path for the technology to be developed further, in an attempt to replace the conventional refrigeration systems, power production and other pollutant energy production systems in the future. The thermo-acoustic field is becoming one of the emerging technologies dealing with conversion of energies. The earth population is growing faster for the planet to sustain its consumption and for the environment to control the pollution. Our home refrigerators are ones of appliances contributing to the pollution of the environment by their toxic coolants and their lubricants. Burning of fossils to produce electricity is another way of contributing to the pollution. Thermo-acoustic device show potential alternative on reducing air pollution. It can be driven by wasted heat, has no toxic coolant and does not require the use of lubricant. Because of these advantages and many others, thermo-acoustic devices are attracting more attention from researchers. However the technology is still in its developing stage because of the currents limitations related to the performance of existing models.
Thermo-acoustic engine convert heat into a sound wave. Previous studies have searched ways and means to improve thermo-acoustic devices performance. Some have chosen to optimise the length and the configuration of the resonator; others have focussed on the gases and their mixtures; while number of researchers has focussed on the materials and configuration of the stack or regenerator, described as the heart of the devices. In the present, study we have pointed out the effect of the variation of some crucial parameters on the performance of thermo-acoustic devices. A travelling-wave thermo-acoustic engine was designed using numerical approximation provided by a modelling code DELTAEC (Design Environment for Low-amplitude Thermo-Acoustic Energy Conversion). The design developed focuses, in particular, on the effects of different ceramic substrate configurations (diameter, length, porosity and position) on the performance of the device. Meaningful comparison on the effect of the ceramic substrates configuration is provided in order to predict the performance of the device. In addition, guidance on the identification and the selection of the best geometrical configurations of ceramic substrates have been provided. The results obtained from the DELTAEC simulation were used to design and build a hermetically sealed travelling-wave thermo-acoustic engine using low cost materials. The device was able to...