Thermodynamics Cycle Mode Analysis Of Thermoacoustic Engine And Design For Miniaturization Thermoacoustic Refrigerator

Thermoacoustic engine is a new type engine. Because it has the advantage of a complete absence of moving mechanical parts, it is a potential miniaturization engine. It operates using environmentally benign fluids as working substance. This advantage can meet well those requirements of the international ban on the production of CFC's. So in the past decade or so, much interest has arisen over the promise of the applicability of the field of thermoacoustic engines.In order to study thermoacoustic effect, new method and new idea must be offered by thermodynamic. Thermoacoustic effect is conversion effect between thermal and acoustic energy. It has exceeded the research field of classical, static state thermodynamics. New research method, which combines thermodynamics and dynamics, must be adopted.The paper builds the medium scale thermodynamic cycle mode in thermoacoustic engines. At the same time, the paper also designed a miniaturization thermoacoustic refrigerator based on the theory of coupling characteristics between frequency and stack. The research work of author's thesis has been focused on following points:1. Serial waveform analyze for the cycle of engine. As a new type engine, on the one hand thermoacoustic engine follows the basic thermodynamic law; on the other hand, it also is a period vibration structure as well as classical engine. Thermoacoustic engine can be divided into three classes -standing wave, traveling wave and the composite according to the phase between the pressure and fluid velocity. The paper analyzed the characteristics of the p- V chart from the view of wave characteristics. The results indicated that the serial waveform is composed of the standing wave and traveling wave and the phase between pressure and fluid velocity promising voluminous extent of the p- V chart. A bridge is build between classical engines and thermoacoustic engines by the characteristic of the vibrationand thermodynamic cycles.2. Thermoacoustic effect is a medium scale thermodynamic cycle. The paper analyzed the thermodynamic cycle mode at the local area equilibrium assumption. The result indicated that it is the parcel of gas which locals near thermal penetration depth converts heat into work. The thermodynamic cycle is multi-heat resource cycle, not Stirling cycle. The parcel of gas undergoing a reversible cycle when the spacing between the plates is roughly Sk; and it undergoing anirreversible cycle when the spacing between the plates is a few Sk, because there isheat and momentum transferred.3. Thermoacoustic effect is the coupling result between stack and gas oscillation. It is necessary to study the coupling characteristic of stack and frequency before someone want to alter or design thermoacoustic refrigerator. The realization of a standing-wave thermoacoustic refrigerator system function depends on the thermoacoustic stack and frequency modulating phase between the pressure and gas velocity, then the resonance being excited. The quality factor is different for different configuration parameter of stack, so the frequency, which can couple phase to realize pumping heat and can excite resonance is an effective frequency bandwidth, not any frequency can do. The stack parameter, which can realize the goal, is an effective bandwidth for a certain frequency vice versa. The operation frequency is higher than the empty resonator's, because the parts of apparatus are placed in the resonator, when the hydraulic radius has dimensions of the order of the thermal penetration depth.4. The paper designed a microminiaturization thermoacoustic refrigerator using the DeltaE procedure. The experimental apparatus has been built.