Investigation On Thermoacoustic Theory And Experiment Of Thermoacoustically Driven Pulse Tube Refrigerators

Thermoacoustic engine is a new type of engine, which is based on the thermoacoustic effect. Due to its simple structure, high reliability, no pollution, no moving part, the thermoacoustic engine has many advantages over the traditional mechanical compressors. And a pulse-tube refrigerator or a thermoacoustic refrigerator driven by a thermoacoustic engine, instead of a traditional mechanical compressor, is expected to be a promising refrigerator system. Therefore, the study of thermoacoustics, including thermoacoustic engine and thermoacoustic refrigerator, is one of the most attractive project in refrigeration engineering field.First, in this paper the author makes a detailed review on the historical developments and the latest advances of the research on thermoacoustics. After the introduction of the basic theory of thermoacoustics, the author puts the emphases on the following issues:1. Second-order Nonlinear Thermoacoustic Theory ModelA two-dimension, second-order thermoacoustic theory model is built based on the universal principle of hydrodynamics. Then, the nonlinear effect, which the presence of second-order physical parameters in thermoacoustic system brings about, is analyzed. And the change of some physical parameters due to the nonlinear effect is discussed. At last, the feasibility of the numerical simulation computation is analyzed simply through investigating if the flow-field equations in this model are closed.2. The Theoretical Model of Rayleigh StreamingA thermoacoustic theory model is presented based on the two-dimension, second-order thermoacoustic theory model, for analysis of Rayleigh streaming in standing thermoacoustic devices. Both the parallel plate and the cylindrical tube geometries are taken into account in this model. Second-order time-averaged mass flux and velocity, in main resonator, regenerator, thermal buffer tube and feedback inertance tube of a standing thermoacoustic system or any closed tube such as pulse tube in pulse tube refrigerator, may be calculated by means of this model, if longitudinal gradient of the pressure andmean temperature, the acoustic pressure and the mean temperature are given. Consequently we may acquire the distribution of Rayleigh streaming in the corresponding system. At last, the author analyses the reason for the production of Rayleigh steaming in a themoacoustic system.3. Resonance Tube in Thermoacousic EngineResonance tube is a very important part of thermoacoustic engine system, so the change of its geometrical paramete has an obvious effect on the thermoacoustic system itself. A series of experimental study on the performance of a cone-shaped resonance tube and a cylindrical resonance tube in the same standing-wave thermoacoustic engine has been carried out for investigating how the geometrical parameter of the resonance tube influences the themoacoustic system. A last, the result of these experiments is briefly analyzed based on the nonlinear effect existing in thermoacoustic system.4. Thermoacoustically Driven Pulse Tube Refrigerator (TADPTR)The author has designed a double-inlet pulse tube refrigerator at the Technical Institute of Physics and Chemistry, in Chinese Academy of Sciencs. An experimental apparatus has been constructed with a standing thermoacoustic engine and the double-inlet pulse tube refrigerator. Then a series of optimization experiments have been carried out. After replacing the double-inlet structure by an inertance tube on the pulse tube refrigerator, we obtained a minimal temperature of 75.IK in the pulse tube refrigerator driven by a traveling thermoacoustic engine. At last, the author analyses the theory of inertance tube based on the thermoacoustic theory.