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目的:大功率脉管制冷机中存在的温度非均匀性问题导致回热器效率低下,严重阻碍制冷机性能的提高。本文回顾回热器非均匀性问题的理论与试验研究,对当前理论与实验的研究结果进行细致的分类与探讨,并展望将来非均匀性研究可能的发展方向。方法:1.当前回热器非均匀性理论与实验研究主要包括形成机理、发展机制和抑制方法三个方面。其中对其形成机理和发展机制的研究以理论为主,抑制方法的研究以实验为主。2.回热器温度非均匀性的形成机理,按照其诱发因素的来源可划分为内源性与外源性因素,其中内源性因素包括与回热器相关和变径流道等,外源性因素包括自然对流效应及外界温度扰动。3.发展机制主要认为是气体粘度与温度之间的正向关系导致的回热器内温度与流阻的正反馈效应。4.抑制方法主要是增加回热器内径向热导率,阻断其发展机制,或增加回热器长径比,抑制其影响范围。结论:1.温度非均匀性形成机制复杂,为多因素耦合作用;2.气体粘度与温度之间的正向关系导致的回热器内温度与流阻的正反馈效应是导致非均匀性发展的主要因素;3.增加回热器径向热导率和回热器长径比可有效抑制非均匀性。
OBJECTIVE: The inhomogeneity of temperature in high-power pulse tube refrigerator leads to the low efficiency of regenerator, which seriously hinders the improvement of refrigerator performance. This paper reviews the theoretical and experimental studies on the heterogeneity of regenerators, and makes a detailed classification and discussion of the current theoretical and experimental research results. Finally, the possible future directions for the research on non-uniformities are prospected. Methods: 1. The current non-uniformity of regenerator theory and experimental research include three aspects: formation mechanism, development mechanism and suppression method. Among them, the research on its formation mechanism and development mechanism is based on theory, and the inhibition method is mainly based on experiments. Regenerator temperature heterogeneity formation mechanism, in accordance with its sources of inducing factors can be divided into endogenous and exogenous factors, including endogenous factors including the regenerator and the reducer, etc., exogenous Sexual factors include natural convection effects and external temperature disturbances. 3. The development mechanism is mainly considered as a positive feedback effect of temperature and flow resistance in the regenerator due to the positive relationship between gas viscosity and temperature. 4. Suppression methods are mainly to increase the radial thermal conductivity of the regenerator, blocking its development mechanism, or increase the aspect ratio of the regenerator, to inhibit its impact range. The formation mechanism of temperature inhomogeneity is complicated, and it is a multi-factor coupling effect. (2) The positive feedback effect between temperature and flow resistance caused by the positive relationship between gas viscosity and temperature leads to the non-uniform development Of the main factors; 3. Increasing the regenerator radial thermal conductivity and regenerator aspect ratio can effectively inhibit the non-uniform.