微型低温节流制冷器结构优化设计

Optimal Design of Miniature Joule-Thomson Cryocooler

J-T节流制冷器被广泛应用于多种红外设备中。在有限结构内达到冷量最大化,是节流制冷器在小型化发展中面临的问题之一。本文在考虑流体物性变化和部件漏热的基础上,建立了一维稳态节流制冷器热力模型,着重对用于节流制冷器的双螺旋翅片换热器中3项结构参数(翅片的肋高、肋厚和肋间距)对换热器性能的影响进行了计算分析,并采用遗传算法对结构参数进行了优化。研究结果表明:论文所进行的数值计算与实验结果吻合较好;在给定工况和结构参数范围内,肋高和肋厚增加会导致换热器的熵产和冷端冷量都增加、肋间距增加则使换热器的熵产和冷端冷量都减少;并存在最优参数使换热器冷端冷量最大。本文所建立的计算方法为J-T节流制冷器在工程应用中的结构优化和设计提供了高效的途径。

The Joule–Thomson(J–T)cryocooler is widely used in a variety of infrared devices.Maximizing the cooling capacity in finite structures is one of the foremost problems in J-T cryocooler miniaturization.In this study,a one-dimensional model based on the thermodynamic properties of real gas and heat leakage of components is established.The effects of three structural parameters(fin height,fin thickness,and fin pitch)used in a helical finned tube heat exchanger on the performance of a cryocooler are calculated and optimized using a genetic algorithm.The results show that the calculated data are in good agreement with the experimental data.In the specific working conditions and structural parameters employed,an increase in fin height and fin thickness would increase the entropy production and cooling capacity of the cold end of the heat exchanger,whereas an increase in fin pitch would have the opposite effect.Optimal parameters exist for maximizing the cooling capacity of the heat exchanger in this study.The analytical method established in this study could provide a simple and effective means of optimizing and designing a J–T in engineering applications.