Improvement of Cooling Effect of Loop-Tube-Type Thermoacoustic Cooling System Applying Phase Adjuster

Sakamoto, Shinichi; Imamura, Yosuke; Watanabe, Yoshiaki

doi:10.1143/jjap.46.4951

Cited by 49 publications

(62 citation statements)

References 12 publications

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“…In the looped-tube type thermoacoustic system, the traveling wave can also store the acoustic energy due to the closed-loop acoustical boundary conditions. Thus, in the loop, the acoustic energy can be stored by both TWC and SWC, which make the acoustic field very complicated [31][32][33]. Therefore, manufacturing errors may significantly affect the acoustic field.…”

Section: Concept Designmentioning

confidence: 99%

A two-stage traveling-wave thermoacoustic electric generator with loudspeakers as alternators

Kang

Cheng

et al. 2015

Applied Energy

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This paper presents the design, construction and tests of a traveling-wave thermoacoustic electric generator. A two-stage travelling-wave thermoacoustic engine converts thermal energy to acoustic power. Two low-impedance linear alternators (i.e., audio loudspeakers) were installed to extract and convert the engine's acoustic power to electricity. The coupling mechanism between the thermoacoustic engine and alternators has been systematically studied numerically and experimentally, hence the optimal locations for installing the linear alternators were identified to maximize the electric power output and/or the thermal-to-electric conversion efficiency. A ball valve was used in the loop to partly correct the acoustic field that was altered by manufacturing errors. A prototype was built based on this new concept, which used pressurized helium at 1.8 MPa as the working gas and operated at a frequency of about 171 Hz. In the experiment, a maximum electric power of 204 W when the hot end temperature of the two regenerators reaches 512℃ and 452℃, respectively. A maximum thermal-to-electric efficiency of 3.43% was achieved when the hot end temperature of the two regenerators reaches 597℃ and 511℃, respectively. The research results presented in this paper demonstrate that multi-stage travelling-wave thermoacoustic electricity generator has a great potential for developing inexpensive electric generators.

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Section: Concept Designmentioning

confidence: 99%

A two-stage traveling-wave thermoacoustic electric generator with loudspeakers as alternators

Kang

Cheng

et al. 2015

Applied Energy

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“…To improve energy conversion efficiency, we proposed installing a hollow circular cylinder, called as a phase adjuster (PA), in a looped tube. 3) Installing PA in a circular tube is equivalent to reducing the tube diameter locally. PA changes acoustic conditions and affects thermoacoustic effects in stacks.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of the effect of local diameter reduction on the critical temperature of thermoacoustic oscillations in a looped tube

Orino

Sakamoto

Inui

et al. 2014

Jpn. J. Appl. Phys.

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The installation of a phase adjuster (PA) has been proposed to improve the cooling effect of loop-tube-type thermoacoustic cooling systems. Installing a PA in a circular tube is equivalent to reducing the tube diameter locally. In this paper, we report our numerical investigation of the effects of the configuration parameters of a PA, i.e., diameter reduction and installation position, on the critical temperature of thermoacoustic gas oscillations by utilizing the transfer matrix method. The PA was modeled considering reflections due to the impedance mismatch at the boundaries between different diameters. The calculation results indicate that the critical temperature significantly decreases when a certain level of diameter reduction at appropriate positions is set, and these results correspond to empirical configurations that were experimentally chosen and verified in past studies.

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“…We have proposed several methods [8][9][10][11][12][13][14][15] to control the phase difference of the generated sound in the prime mover in a thermoacoustic system. We have considered that the phase difference in the prime mover is important to energy conversion in the thermoacoustic system.…”

Section: Introductionmentioning

confidence: 99%

“…We suggested various methods to control the phase difference 0 degree or near 0 degree without dampening the advantage of the loop-tube-type thermoacoustic system(loop tube). For example, we have successfully reduced the cross section of the loop tube, which we call the phase adjuster(PA) [8][9][10] and have developed methods to connect the resonant tube to a loop tube [11][12][13] , as well as methods to set up a thin film in a system 14 . A phase adjuster in a cylindrical shape was used in past experiments.…”

Section: Introductionmentioning

confidence: 99%

Introduction of conical phase adjuster for thermoacoustic system

Sakamoto¹,

Inoue²,

Nakano³

et al. 2013

Proceedings of Meetings on Acoustics

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We have proposed a phase adjuster for the thermoacoustic system and succeeded in improving the energy conversion efficiency from heat to the sound. A phase adjuster in a cylindrical shape was used in the past experiments. In this report, a conical phase adjuster is introduced. The inside diameter in one side of the phase adjuster is 20.5mm, and the other is 39.5mm. The length of phase adjuster is 45mm.The phase adjuster is placed in two ways; the larger inner diameter of the phase adjuster is placed in the left side and the smaller is in the right (with PA L39.5 R20.5); the smaller inner diameter is in the left and the larger is in the right (with PA L20.5 R39.5).The total length of the loop is 3.3 m and the phase adjuster is placed 1.125 m away from the upper end of the prime mover stack in the clockwise direction. The measurements are conducted in three conditions: without phase adjuster and with each phase adjusters. Both the sound pressure and sound intensity generated in the thermoacoustic system with phase adjuster are greater than those without phase adjuster. The biggest sound intensity is observed with PA L39.5 R20.5.

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Improvement of Cooling Effect of Loop-Tube-Type Thermoacoustic Cooling System Applying Phase Adjuster

Cited by 49 publications

References 12 publications

A two-stage traveling-wave thermoacoustic electric generator with loudspeakers as alternators

A two-stage traveling-wave thermoacoustic electric generator with loudspeakers as alternators

Numerical analysis of the effect of local diameter reduction on the critical temperature of thermoacoustic oscillations in a looped tube

Introduction of conical phase adjuster for thermoacoustic system

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