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基于多孔材料边界层动力理论 ,对低温制冷机或热声热机中回热器内的流动特性分析引入临界频率的概念。当频率高于该临界值时 ,系统内假定的泊肃叶 (Poiseuille)流将会被破坏 ,由此会极大地造成压力波的衰减。期望这一概念有助于回热器内动力损失的研究。我们对 7种不同目数丝网和 4种工质 (氦、氮、氩和氢 )进行了计算 ,结果表明临界频率与丝网尺寸以及工作流体的种类有关 ,而且在气体区域随温度而增大 ,在液体区域则相反。
Based on the theory of boundary layer dynamics of porous materials, the concept of critical frequency is introduced into the analysis of flow characteristics in regenerator in cryogenic refrigerator or thermoacoustic engine. When the frequency is above this threshold, the presumed Poiseuille flow in the system will be destroyed, thereby greatly damaging the pressure wave. The expectation of this concept contributes to the study of the power loss in the regenerator. We calculated seven different mesh meshes and four working fluids (helium, nitrogen, argon and hydrogen) and found that the critical frequency was related to the size of the screen and the type of working fluid, and also increased with temperature in the gas zone Large, in the liquid area is the opposite.