四级环路行波热声发动机系统起振特性分析

Analysis of Onset Characteristics of a 4-Stage Looped Thermoacoustic Prime Mover

起振过程是热声发动机中最重要的过程之一,起振温度的高低直接关系到系统可以利用的能源品位。本文以四级环路行波热声发动机为研究对象,建立了二维数值模型,利用FLUENT软件对该系统的起振过程进行了模拟与分析。通过FFT分析方法对系统的起振过程进行了描述并探讨了充气压力对起振温度的影响。结果显示,在本文的计算条件下,以CO_2为工质时较高的充气压力更有利于降低系统的起振温度。

Onset process is one of the most significant processes in a thermoacoustic prime mover,and the onset temperature is directly relevant to the usability of low-grade heat source in driving the thermoacoustic prime mover.A 2-dimensional numerical model of the 4-stage looped thermoacoustic engine has been proposed to simulate and analyze the onset process of the prime mover with FLUENT.Based on the FFT analysis,the onset process is described and the influence of filling pressure on the onset temperature is then discussed.The results from our simulation show that a higher filling pressure helps to reduce the onset temperature,when CO_2 is adopted as the working fluid.