Study On The 4-stage Looped Thermoacoustic Engine At High Pressures

Thermoacoustic engine is a novel pressure wave generating device based on thermoacoustic effects,which has the merits of simplicity,reliability and none pollution because it has no moving part and its working fluids are generally inert gases,while there are also some disadvantages,such as small pressure ratio and low power density.A higher working pressure can help to increase the pressure amplitude,which can then increase the power density.In this work,an experimental setup of 4-stage looped travelling-wave thermoacoustic engine for high-pressure operating conditions has been built for the related research as follows:1.A simulation model of 4-stage looped travelling-wave thermoacoustic engine based on linear thermoacoustic effect has been built.The profiles of temperature,pressure amplitude and phase,volumetric velocity amplitude and phase,nondimensional acoustic impedance,acoustic power in the system are then calculated with the model.The results show that the profiles of these parameters in each unit are the same to those in another unit,except for the pressure phase and the volumetric flow rate phase,which are in symmetrical mode.2.For simplicity,the simulation is only conducted for one stage of the engine,thanks to its symmetricity,to analyze the influences of cross sectional area ratio,heat exchanger,regenerator,thermal buffer tube,resonator and RC load on the performance parameters including pressure amplitude,efficiency and heating power,based on which,an optimized design with the helium of 6MPa as working fluid has been done.3.An experimental setup of 4-stage looped travelling-wave thermoacoustic engine based on the optimized design has been built up.The experiments without load have then been done to learn the influence of screen mesh,working fluids,and heating power to the system performance at different pressures condition,focusing on the pressure amplitude and heating temperature.The simulated and experimental results under different pressures and heating power operating conditions have been then compared.Preliminarily experiments with load at high pressure conditions have also been done.