液氦温区两级4K脉冲管制冷机数值模拟

NUMERICAL STUDY OF A TWO-STAGE 4K-PULSE TUBE CRYOCOOLER OPERATING AT LIQUID HELIUM TEMPERATURE RANGE

为模拟和动态显示工作在液氦温区的两级4K脉冲管制冷机内部工作过程和参数变化规律,发展了一种新的欧拉法-拉格朗日法数值计算模型。采用拉格朗日方法,直接跟踪脉冲管中气体微元随周期性压力波动的具体运行轨迹;采用欧拉法,直接模拟蓄冷器内部的动态参数变化。本文简单介绍该模型,并模拟了一典型两级4 K脉冲管制冷机各参数的变化情况,分析了多层磁性蓄冷材料对制冷机性能的影响情况。

A new mixed Eulerian-Lagrangian computational model for simulating and visualizing the internal processes and the variations of dynamic parameters of a two-stage 4 K pulse tube cryocooler has been developed. We use the Lagrangian method, a moving grid, to follow the exact tracks of gas particles as they move with pressure oscillation in the pulse tube to avoid any numerical false diffusion. The Eulerian approach, a fixed computational grid, is used to simulate the variations of dynamic parameters in the regenerator. The time-variations of dynamic parameters are calculated in the paper. Attention is paid to the effects of different regenerative materials on the performance of the 4 K two-stage pulse tube cooler.