共查询到19条相似文献,搜索用时 171 毫秒
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在热声发动机系统中,谐振管用来调节系统的超振频率.通常的四分之一波长谐振管由一段谐振管后面连接一个比较大的气体容积构成,与二分之一波长谐振管相比,在相同的起振频率下前者可以有相对短的管长.锥形谐振管除了调节频率外,还可以提高热声发动机输出压力波的压比.本文通过数值计算软件Fluent6.0中的K-ε湍流模型模拟了不同长度、不同的进出口直径的一系列锥形谐振管,得出了近似四分之一波长锥形谐振管的共振频率与其长度、锥度之间的关系,并初步与实验进行了对照. 相似文献
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采用计算流体动力学(CFD)方法,对高频驻波热声发动机和热声斯特林发动机实验系统分别进行了二维和三维数值模拟。计算模型具有与实验系统相同的几何结构、尺寸和运行工况。对计算模型的有效性进行了研究,表明实现有限换热条件的板叠实物模型适合驻波热声发动机的模拟,而实现局域热平衡的多孔介质模型适合热声斯特林发动机的模拟。计算结果成功观测到了非线性的自激振荡演化过程,捕捉到了两种发动机的不同非线性现象。计算结果分别给出了两种热声发动机内部的声场分布特性和复杂流场。计算结果与实验结果的对比验证了CFD方法对高频驻波热声发动机和热声斯特林发动机模拟的有效性。 相似文献
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针对热声发动机起振过程中复杂的温度变化,在自行研制的"驻波型热声发动机试验平台"上,开展了在不同的工质类型、充气压力等试验工况下,热声发动机起振过程的轴向温度分布规律和变化特征的试验研究,试验结果表明:对于氮气、氩气而言,其系统温度动态特性规律基本一致,且热声核温度梯度和热声板叠温度梯度存在较明显的差别;而对于氦气,其系统温度动态特性不同于前两类气体,且热声核的温度梯度和热声板叠温度梯度的差别十分微弱,可见,不同的工质类型将直接影响到发动机起振过程系统温度的动态变化特性. 相似文献
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热声发动机的起振过程是一个产生并维持自激振荡的过程, 研究热声自激振荡机理有助于进一步了解热声效应的实质. 根据热声网络理论, 建立了驻波热声发动机的整机网络. 将热声网络比拟成电网络, 利用厄米特式计算了输入热声网络的视在功流, 功流平衡对应自激, 在角频率虚部为零的情况下计算了热声发动机的阈值温度和运行频率. 结果表明, 计算值与实验值符合得较好, 充气压力与阈值温度和运行频率的耦合关系大致相同. 所得结论有助于进一步探究热声效应机理以及热声发动机系统的优化设计. 相似文献
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Thermoacoustic engines convert heat energy into high amplitude sound waves, which is used to drive thermoacoustic refrigerator or pulse tube cryocoolers by replacing the mechanical pistons such as compressors. The increasing interest in thermoacoustic technology is of its potentiality of no exotic materials, low cost and high reliability compared to vapor compression refrigeration systems. The experimental setup has been built based on the linear thermoacoustic model and some simple design parameters. The engines produce acoustic energy at the temperature difference of 325–450 K imposed along the stack of the system. This work illustrates the influence of stack parameters such as plate thickness (PT) and plate spacing (PS) with resonator length on the performance of thermoacoustic engine, which are measured in terms of onset temperature difference, resonance frequency and pressure amplitude using air as a working fluid. The results obtained from the experiments are in good agreement with the theoretical results from DeltaEc. 相似文献
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A simplified physical model for calculating the onset temperature ratio and the frequency of a standing wave thermoacoustic engine (SWTE) in the time domain is built based on thermodynamic analysis. Coefficients of transient pressure drop and heat transfer are first deduced from linear thermoacoustic theory. By numerical computation, the evolutions of the pressure amplitude and the spectrum characteristics during the onset process are presented. Furthermore, the effects of stack spacing, charge pressure, and resonator length on the onset temperature ratio and the frequency are calculated. Relatively good agreement between the computational and the experimental results has been achieved, which validates the model for calculating the onset characteristics. 相似文献
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Thermoacoustic prime movers can generate pressure oscillation without any moving parts on self-excited thermoacoustic effect. The details of the numerical simulation methodology for thermoacoustic engines are presented in the paper. First, a four-port network method is used to build the transcendental equation of complex frequency as a criterion to judge if temperature distribution of the whole thermoacoustic system is correct for the case with given heating power. Then, the numerical simulation of a thermoacoustic-Stirling heat engine is carried out. It is proved that the numerical simulation code can run robustly and output what one is interested in. Finally, the calculated results are compared with the experiments of the thermoacoustic-Stirling heat engine (TASHE). It shows that the numerical simulation can agrees with the experimental results with acceptable accuracy. 相似文献
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热声发动机作为一种完全没有运动部件的能量转化和传输机械具有广阔的应用前景.为了提高热声发动机的驱动性能,本文采用变负载法对热声发动机性能的影响因素进行了实验研究.实验结果表明,负载的阻力和容抗对热声发动机的加热温度、压比和声功引出有重要影响.同时,实验中还发现了能够使热声发动机瞬时消振和起振的实验方法,将极大方便对热声发动机的开关控制. 相似文献