Performance analysis on a looped thermoacoustic refrigeration system driven by thermoacoustic engine

doi:10.11949/j.issn.0438-1157.20161350

Abstract

Abstract:

Thermoacoustic heat engine is a type of energy conversion machine with the merits of high reliability and environmental friendliness.The present work focuses on a looped travelling-wave thermoacoustic refrigerator with one thermoacoustic engine stage and one thermoacoustic refrigerator stage,connected by resonators.The required acoustic field for an efficient travelling-wave thermoacoustic system is featured by high acoustic impedance and appropriate phase relation close to travelling wave in the regenerator.In the presented thermoacoustic refrigerator,the installation positions of the regenerators could dramatically affect the acoustic field inside them,due to the fact that the acoustic field is highly sensitive to the variation in acoustic impedance.In order to investigate the effect of the installation locations of the thermoacoustic cores on the performance of the thermoacoustic refrigerator,the looped travelling-wave thermoacoustic refrigerator is simulated with DeltaEC,which is a software widely used for the simulation of thermoacoustic systems.In the simulation,the working fluid is helium at a mean pressure of 3 MPa,and the heating temperature and the cooling temperature are 227℃ and 0℃,respectively.The overall coefficient of performance of the whole system,the efficiency of the engine stage,the coefficient of performance of the refrigerator stage,the acoustic impedance and the phase difference in the two regenerators with different installation positions of the two regenerators have been analyzed.According to the simulation results,when the ratio of the distance from the engine's regenerator to the refrigerator's regenerator in the direction of the acoustic wave to the loop length is 0.24,the maximum overall coefficient of performance can be reached,corresponding to a relative Carnot overall coefficient of 0.13.When the ratio is within 0.21-0.26,the two regenerators can both achieve efficient thermoacoustic conversion,leading to high performance of the whole system.However,when it is larger than 0.26 or smaller than 0.21,the performance of the two regenerators will deteriorate,leading to poor performance of the whole system.

Key words: thermodynamic process, thermoacoustic engine, thermoacoustic refrigeration, optimal design, regeneration, numerical simulation

摘要：

热声热机是一种具有高可靠性和环保特性的无运动部件热机。研究对象是一种环路行波热声发动机驱动的热声制冷机，由一个热声发动机单元和一个热声制冷机单元串联成环路组成。高效的行波热声系统要求回热器处在高声阻抗和接近行波的声场中。由于在环路系统中，声场对声阻抗的变化极为敏感，系统中两个回热器的安装位置会极大影响回热器处的声场。为了研究热声核安装位置对系统性能的影响情况，利用DeltaEC对该系统进行了数值模拟，分析了两个热声核在不同安装位置时系统的总能效系数、发动机单元的效率、制冷机单元的能效系数以及两个回热器的平均相位差和声阻抗等。根据计算结果，当制冷机单元回热器沿声功传输方向距发动机单元回热器的距离与环路总长的比值为0.24时，系统可达到最大总能效系数0.45，对应的相对卡诺能效系数是0.13。当该比值的范围在0.21~0.26时，两个回热器的平均声阻抗较大，使系统的总体性能较优。当该比值大于0.26或小于0.21时，制冷机单元回热器和发动机单元回热器的性能都会恶化，造成了系统整体性能的不佳。

关键词: 热力学过程, 热声发动机, 热声制冷, 优化设计, 回热, 数值模拟

CLC Number:

TB511

YANG Rui, WANG Yi, FENG Ye, JIN Tao. Performance analysis on a looped thermoacoustic refrigeration system driven by thermoacoustic engine[J]. CIESC Journal, 2016, 67(S2): 298-303.

杨睿, 王祎, 封叶, 金滔. 环路热声发动机驱动的热声制冷系统性能分析[J]. 化工学报, 2016, 67(S2): 298-303.

References 20

[1]	JIN T,HUANG J,FENG Y,et al.Thermoacoustic prime movers and refrigerators:thermally powered engines without moving components[J].Energy,2015,93:828-853.
[2]	BACKHAUS S,SWIFT G W.A thermoacoustic Stirling heat engine[J].Nature,1999,399:335-338.
[3]	Ceperley P H.A pistonless Stirling engine-the travelling wave heat engine[J].Journal of the Acoustical Society of America,1979,66(5):1508-1513.
[4]	QIU L M,SUN D M,YAN W L,et al.Investigation on a thermoacoustically driven pulse tube cooler working at 80K[J].Cryogenics,2005,45(5):380-385.
[5]	JIN T,CHEN G B,SHEN Y.A thermoacoustically driven pulse tube refrigerator capable of working below 120 K[J].Cryogenics,2001,41(8):595-601.
[6]	TANG K,BAO R,CHEN G B,et al.Thermoacoustically driven pulse tube cooler below 60K[J].Cryogenics,2007,47(9):526-529.
[7]	HU J Y,LUO E C,DAI W,et al.A heat-driven thermoacoustic cryocooler capable of reaching below liquid hydrogen temperature[J].Chinese Science Bulletin,2007,52(4):574-576.
[8]	CHEN G,QIU L,ZHENG J,et al.Experimental study on a double-orifice two-stage pulse tube refrigerator[J].Cryogenics,1997,37(5):271-273.
[9]	UEDA Y,BIWA T,MIZUTANI U,et al.Experimental studies of a thermoacoustic Stirling prime mover and its application to a cooler[J].The Journal of the Acoustical Society of America,2004,115(3):1134-1141.
[10]	KANG H,ZHOU G,LI Q.Heat driven thermoacoustic cooler based on traveling-standing wave[J].Energy Conversion and Management,2010,51(11):2103-2108.
[11]	LUO E,DAI W,ZHANG Y,et al.Thermoacoustically driven refrigerator with double thermoacoustic-Stirling cycles[J].Applied physics letters,2006,88(7):074102.
[12]	YU B,LUO E C,LI S F,et al.Experimental study of a thermoacoustically-driven traveling wave thermoacoustic refrigerator[J].Cryogenics,2011,51(1):49-54.
[13]	ZHANG X,CHANG J.Onset and steady-operation features of low temperature differential multi-stage travelling wave thermoacoustic engines for low grade energy utilization[J].Energy Conversion and Management,2015,105:810-816.
[14]	YU Z,JAWORSKI A J,BACKHAUS S.Travelling-wave thermoacoustic electricity generator using an ultra-compliant alternator for utilization of low-grade thermal energy[J].Applied Energy,2012,99:135-145.
[15]	ZHANG X,CHANG J,CAI S,et al.A multi-stage travelling wave thermoacoustic engine driven refrigerator and operation features for utilizing low grade energy[J].Energy Conversion and Management,2016,114:224-233.
[16]	JIN T,YANG R,WANG Y,et al.Acoustic field characteristics and performance analysis of a looped travelling-wave thermoacoustic refrigerator[J].Energy Conversion and Management,2016,123:243-251.
[17]	SWIFT G W.Thermoacoustics:A Unifying Perspective for Some Engines and Refrigerators[M].New York:Acoustical Society of America,American Institute of Physics Press,2002:81-113.
[18]	CLARK J P,WARD W C,SWIFT G W.Design environment for low-amplitude thermoacoustic energy conversion(DeltaEC)[J].The Journal of the Acoustical Society of America,2007,122(5):3014-3014.
[19]	WANG K,SUN D,ZHANG J,et al.Operating characteristics and performance improvements of a 500W traveling-wave thermoacoustic electric generator[J].Applied Energy,2015,160:853-862.
[20]	KANG H,CHENG P,YU Z,et al.A two-stage traveling-wave thermoacoustic electric generator with loudspeakers as alternators[J].Applied Energy,2015,137:9-17.