Transmission characteristics of acoustic amplifier in thermoacoustic engine

Thermoacoustic engines are promising in practical applications for the merits of simple configuration, reliable operation and environmentally friendly working gas. An acoustic amplifier can increase the output pressure amplitude of a thermoacoustic engine (TE) and improve the matching between the engine and its load. In order to make full use of an acoustic amplifier, the transmission characteristics are studied based on linear thermoacoustic theory. Computational and experimental results show that the amplifying ability of an acoustic amplifier is mainly determined by its geometry parameters and output resistance impedance. The amplifying ability of an acoustic amplifier with appropriate length and diameter reaches its maximum when the output resistance impedance is infinite. It is also shown that the acoustic amplifier consumes an amount of acoustic power when amplifying pressure amplitude and the acoustic power consumption increases with amplifying ratio. Furthermore, a novel cascade acoustic amplifier is proposed, which has a much stronger amplifying ability with reduced acoustic power consumption. In experiments, a two-stage cascade acoustic amplifier amplifies the pressure ratio from 1.177 to 1.62 and produces a pressure amplitude of 0.547 MPa with nitrogen of 2.20 MPa as working gas. Good agreements are obtained between the theoretical analysis and experimental results. This research is instructive for comprehensively understanding the mechanism and making full use of the acoustic amplifier.

[1]  Tao Jin,et al.  A thermoacoustically driven pulse tube refrigerator capable of working below 120 K , 2001 .

[2]  C. M. Martín,et al.  Pulse tube cryocoolers for industrial applications , 2002 .

[3]  Gregory W. Swift,et al.  DESIGN ENVIRONMENT FOR LOW-AMPLITUDE THERMOACOUSTIC ENGINES , 1994 .

[4]  Gregory W. Swift,et al.  Analysis and performance of a large thermoacoustic engine , 1992 .

[5]  Gregory W. Swift,et al.  Simple harmonic analysis of regenerators , 1996 .

[6]  Shuliang Zhou,et al.  Experimental research of thermoacoustic prime mover , 1998 .

[7]  Zhihua Gan,et al.  Investigation on a thermoacoustically driven pulse tube cooler working at 80 K , 2005 .

[8]  W. Dai,et al.  A Heat-driven thermoacoustic cooler capable of reaching liquid nitrogen temperature , 2005 .

[9]  W. P. Arnott,et al.  Thermoacoustic engines , 1991, IEEE 1991 Ultrasonics Symposium,.

[10]  Ray Radebaugh,et al.  Development of the pulse tube refrigerator as an efficient and reliable cryocooler , 1999 .

[11]  G. Swift,et al.  A thermoacoustic Stirling heat engine , 1999, Nature.

[12]  Guobang Chen,et al.  Influence of resonance tube length on performance of thermoacoustically driven pulse tube refrigerator , 2005 .

[13]  R. Radebaugh,et al.  Development of a thermoacoustically driven orifice pulse tube refrigerator , 1990 .

[14]  Guobang Chen,et al.  Investigation on traveling wave thermoacoustic heat engine with high pressure amplitude , 2005 .

[15]  Luwei Yang,et al.  High frequency two-stage pulse tube cryocooler with base temperature below 20 K , 2005 .

[16]  Ercang Luo,et al.  An acoustical pump capable of significantly increasing pressure ratio of thermoacoustic heat engines , 2006 .

[17]  G. Swift.  Thermoacoustics: A Unifying Perspective for Some Engines and Refrigerators , 2017 .