Two-port network model and startup criteria for thermoacoustic oscillators
Two-port network model and startup criteria for thermoacoustic oscillators作者机构:Institute of Refrigeration and Cryogenics Huazhong University of Science and Technology Wuhan 430074 China
出 版 物:《Chinese Science Bulletin》 (Chin. Sci. Bull.)
年 卷 期:2009年第54卷第2期
页 面:335-343页
核心收录:
学科分类:080904[工学-电磁场与微波技术] 0809[工学-电子科学与技术(可授工学、理学学位)] 08[工学]
基 金:Supported by National Natural Science Foundation of China (Grant Nos. 50576024 and 51076013)
摘 要:The startup process of a thermoacoustic engine is a self-excited oscillation process generated in inhomogeneous acoustic media. To reveal these coupling relations between various influential factors is an important task of basic research on thermoacoustics. In this paper thermoacoustic engines are regarded as thermoacoustic oscillators consisting of the active network and the passive network. Accordingly, the two-port Y-parameter for relevant component is derived, and standing wave and traveling wave thermoacoustic engine are described by the negative-resistance and feedback model, respectively. The relevant two-port network topology is given as well. The startup criteria for thermoacoustic oscillators are obtained by using Nyquist instability criterion. The model prediction of startup parameters, particularly, startup frequency and mode characteristic are in agreement with that of experimental results reported in the literature. Moreover, with topological graphs it is verified that standing wave engines would start up in a negative-resistance state and there would exist high frequency modes in thermoacoustic-Stirling engines. By investigating into the frequency response of thermoacoustic system, this method proposed can achieve such an objective that these effects of operating and structural parameters of engine on startup modes and startup temperature can be revealed in an analytical way. Thus this approach to test and check thermal stability can be provided in a design phase, instead of using empirical frequency to design thermoacoustic systems.