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Study on the Characteristics of Regenerator of Thermoacoustic Engine

Author: LiuZuo
Tutor: QiuLiMin
School: Zhejiang University
Course: Refrigeration and Cryogenic Engineering
Keywords: Thermoacoustic engine Regenerator CFD simulation
CLC: TB651
Type: Master's thesis
Year: 2010
Downloads: 71
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Abstract

Thermoacoustic engine thermoacoustic effect of the new power machinery. No mechanical moving parts of the machine, can be heat-driven, commonly used working fluid is an inert gas, has outstanding advantages of simple structure, high reliability, environmentally friendly. Driven by the refrigeration and power generation system has broad application prospects. Recuperator (or stack) thermoacoustic engine thermal power into place, so always is the relentless pursuit of the goal of researchers to improve the performance of the regenerator. Throughout the the thermoacoustic development history, every leap of thermoacoustic technology along with the deepening of researchers regenerator knowledge and innovation. This article focused on traveling wave and standing wave thermoacoustic engine regenerator (stack) characteristics to carry out theoretical and experimental research, major achievements are as follows: 1, the concept of traveling wave thermoacoustic engine multi-stage regenerator and CFD simulation and optimization for the the existing Stirling thermoacoustic engine system exists recuperator heat loss and loss of power, combined with the characteristics of nonlinear variation of the physical properties of the working fluid temperature, this paper presents the concept of multi-stage regenerator. Using CFD calculation method and software DeltaE existing thermoacoustic Stirling engine modeling, simulation system with nitrogen as working fluid, the inflation pressure 2MPa and heater temperature of 766K when the pressure amplitude, velocity amplitude and temperature distribution. CFD simulation, laminar flow model in addition to the regenerator, the whole turbulence model. The calculation results obtained by the two methods contrast found with the experimental results: (1) CFD and DeltaE calculation results show that, under the same conditions, the paper proposes a multi-stage regenerative engine performance than the prototype engine. (2) CFD calculated original Stirling thermoacoustic engine at a specific location (sound volume, resonance tube inlet, the tapered resonator inlet) pressure amplitude results than linear thermoacoustic software DeltaE results obtained closer to the experimental value. (3) CFD calculation to get start-up non-linear axial temperature distribution after the recuperator, DeltaE the results of a linear distribution, CFD results with experimental measurements of temperature distribution is more consistent CFD method thermoacoustic The distribution of the temperature of the system has a better prediction. At the same time, the CFD calculated linear distribution tends to be more multi--stage regenerator axial temperature distribution than the original Stirling regenerator. Description of multi-stage regenerator help reduce back to the loss of heat inside the DC. The article also analyzed the flow field on the the whole CFD simulation model of three-way at, there flow field caused dramatic changes due to pressure and speed the flow pattern within one cycle of complex flow pattern of the boundary layer separation, whirlpool, caused a large energy loss. In order to further improve the performance of thermoacoustic engine, which provides direction for improvement. 2, the output characteristics of the standing wave thermoacoustic engine mesh stack and experimental study of this article from damper timing use DeltaE design a small mesh type standing wave thermoacoustic engine, build a bench. Preliminary experiments showed that the thermoacoustic engine using screen stack better performance can be obtained when 18 mesh screen with nitrogen as the working fluid in the inflation pressure of 2.2MPa obtained 0.2017MPa pressure amplitude. On this basis, to carry out a different stack parameters under the whole output characteristics of experimental study results showed that the wire mesh stack within certain parameters, corresponding to the optimum working range: low inflation pressure, low-mesh wire network corresponding to the heater temperature rise rate is small, the wide range of heating power, the optimal machine output performance can be obtained; gradually decreases with the rise of the inflation pressure, the heater temperature rise rate when the high-mesh wire mesh, heating wider power range, the optimum machine output performance can be obtained. Besides, the experimental observation of a standing wave thermoacoustic engine in a variety of screen mesh from the pressure of the process of vibration frequency timing rule: start-up: the frequency reached first eigenfrequencies, the pressure amplitude is only a slight increase, the pressure amplitude The only substantial surge; continue to accumulate to a certain degree in the energy of vibration: the pressure amplitude of the first substantial decline, then the eigenfrequencies disappeared.

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