Research On Network Model Theory And Experimental Of Traveling-wave Thermoacoustic Engine

Thermoacoustic engine is a device for generating mechanical power by thermoacoustic effect. Unlike conventional mechanical compressor, It has the characteristics of no moving parts, simple structure, high reliability, long life;Inert gas can be used as the working fluid, which has no environmental pollution, high environmental performance;It can also use a driving source of low grade heat source with energy utilization of high performance. Therefore, in the modern technologies of new energy utilization, thermoacoustic engine has great development potential and broad prospects.Currently, numerical simulation of thermoacoustic machine is payed more and more attention in the process of thermal acoustics research. Through the thermoacoustic system simulation, thermodynamic properties of the system can be predicted, which can be a great help for the experimental study of thermoacoustic system and design of thermoacoustic engine. Generally it believes that the efficiency of the traveling-wave thermoacoustic device higher than standing equipment. Thus, the study of the traveling-wave thermoacoustic heat engine has become a hot topic in the field of thermoacoustics.In this paper, distributed parameter method and the transfer matrix equation is put to use to calculate the resonant frequency of the traveling wave thermoacoustic engine. The oscillation frequency is obtained in the form of a complex frequency, which real part represents actual frequency and imaginary part is attenuation degree of pressure amplitude. The frequency of the system is compared in the case of the different structure parameters and operating parameters and the influence of various parameters on the resonant frequency of the system is obtained.The system frequencies that have been calculated should be substituted into each transmission matrix equation to conduct numerical simulation of acoustic field distribution characteristics which consist of fluctuating pressure amplitude, volumetric flow rate amplitude, phase difference between the pressure flow and acoustic power flow in a traveling-wave thermoacoustic engine system. So, we can obtain a deeper understanding of sound field distribution in this kind of engine.On the basis of numerical calculation, preliminary experimental study is carried out on a traveling wave type heat engine developed with the DeltaEC software, which nitrogen acts as the working fluid. As a result, under the same heating power, the heating temperature decreases gradually with the increase of working pressure. When the pressure is certain, with the increase of heating power, heating temperature also shows a rising trend and system has a greater pressure ratio that means the work capacity of thermoacoustic system is stronger. Therefore, the temperature of the system can be controlled by adjusting the heating power, and then pressure ratio and thermoacoustic conversion efficiency of the system can be improved.