Application Research Of Acoustic Amplifier In Traveling Wave Thermoacoustic Power Generation System

Thermoacoustic power generation technology is a technology in which a thermoacoustic engine drives a linear alternator and generates electricity based on a thermoacoustic effect.Thermoacoustic engine has the characteristics of simple structure,no moving parts,environmental protection without pollution,and using low-grade thermal energy.Domestic and foreign researchers are very interested in the research of thermoacoustic power generation by using low-grade thermal energy.Among many energy power generation technology applications,thermoacoustic power generation technology has shown great potential for development.Traveling wave thermoacoustic engine driving linear alternator is the main research direction of thermoacoustic power generation technology,however,current traveling wave thermoacoustic engines have problems such as unstable output pressure ratio,low thermalacoustic conversion efficiency,and inaccurate acoustic impedance matching between thermoacoustic engines and linear alternator.In this paper,experimental and simulated methods are used to study output performance of traveling wave thermoacoustic engine and acoustic impedance matching with linear alternator.Details as follows:(1)Based on existing traveling wave thermoacoustic engine system in this laboratory,an acoustic amplifier capable of improving output pressure ratio of traveling wave thermoacoustic engine is designed by using DeltaEC software,and influence of acoustic amplifier on the performance of traveling wave thermoacoustic engine is analyzed through experiments.Mainly with or without acoustic amplifier,traveling wave thermoacoustic engine starting temperature,output pressure amplitude(pressure ratio)and operating frequency of system,and use of variable load method to study sound output of system with acoustic amplifier.Results show that acoustic amplifier has an increasing effect on output pressure ratio of the traveling wave thermoacoustic engine,and can reduce operating frequency of system to a certain extent,which is beneficial to mechanical resonance state with linear alternator.In addition,acoustic amplifier has a negative impact on system's start-up,and can improve system's output sound power within a certain acoustic impedance range,indicating that acoustic amplifier may also become a power-consuming component of system.(2)Acoustic impedance matching problem between traveling wave thermoacoustic engine with acoustic amplifier and linear alternator is studied.Influence of acoustic impedance of the output position of thermoacoustic engine on the output parameters of acoustic amplifier ending is simulated by using DeltaEC software.Thus,the optimal acoustic impedance range is obtained when traveling wave thermoacoustic engine and the linear alternator are matched by acoustic amplifier.At the same time,the method of adjusting acoustic impedance at linear alternator is obtained by analyzing linear alternator network model to match output acoustic impedance of traveling wave thermoacoustic engine.