【作者】 李晓明；

【导师】 陈国邦； 罗二仓；

【作者基本信息】 浙江大学 ， 制冷与低温工程， 2005， 博士

【摘要】 热声发动机是一种完全新型的热力机械,它遵循热声效应机理,与传统的压缩机相比,具有结构简单、运行可靠、寿命长、无污染、无运动部件等诸多优点。由热声发动机取代常规压缩机来驱动脉冲管制冷机或热声制冷机极具潜力,因而,热声机械(包括热声发动机和热声制冷机)成为制冷界的一个研究热点。 本文首先回顾了热声机械的发展历史和最新成果,介绍了热声机械工作原理,重点研究了热声理论及其实验中的若干问题:1.热声二阶非线性理论模型 以流体力学基本原理为基础建立了热声系统的二维二阶理论模型,分析了由于系统中二阶物理量的存在所引发的非线性效应,讨论了热声系统中若干物理量由于非线性效应所带来的变化。最后,通过对该理论模型中流场方程的封闭性研究,分析了进行数值模拟计算的可行性。2.Rayleigh声流模型 根据热声二维二阶理论模型推导了一般驻波型热声系统中二阶时均流速的表达式,该表达式包含了无限大平板和圆管两种模型,已知系统的平均压力、平均温度、平均温度梯度、纵向压力梯度,即可求出相应的二阶时均流速及二阶时均比质量流,从而得知系统中Rayleigh流的分布情况。可以计算的系统不仅包括热声设备的各部分(谐振管、回热器、反馈管、热缓冲管),而且依然适用脉冲管制冷机中脉冲管这类封闭管道的交变流动设备。另外,通过对该模型的分析,提出了Rayleigh声流产生的机理。3.热声谐振管 谐振管作为热声发动机的重要部件之一,其几何参数的变化对热声系统的工作性能有重大影响,作者对驻波型热声发动机的锥形谐振管和圆直谐振管进行了初步的实验对比,以探明谐振管的形状对热声发动机系统性能的影响。其后,基于热声系统存在的非线性效应对实验结果进行了分析。更多还原

【Abstract】 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.更多还原