推移活塞的装配状态对分置式斯特林制冷机性能的影响

The influence of assembly state of displacer on the performance of split Stirling refrigerator

推移活塞在膨胀气缸中的工作频率对分置式斯特林制冷机的性能有较大影响,而结构设计、冷热两端压差、回热器阻力、制冷工质的粘性力、活塞阻尼等因素又影响着工作频率。其中,粘性力和活塞阻尼受推移活塞装配状态的影响而具有一定的随机性。研究了推移活塞装配状态、活塞摩擦系数对斯特林制冷机性能的影响,结果表明,在同轴装配条件下,推移活塞和气缸间隙越小,粘性力增加越快,但总体粘性力较小;非同轴装配条件下,偏心率低于0.75时,推移活塞所受到工质粘性力较小,但偏心率达到0.99时,工质粘性力迅速增加;影响制冷机性能的推移活塞阻力的主要来源是摩擦力,与粘性力同量级的摩擦力对分置式斯特林制冷机性能影响较小。

The working frequency of the displacer in the expansion cylinder, which is affected by the structural design, the pressure difference between the warm and cold ends, the resistance of the regenerator, viscosity of the refrigerant, the piston damping and other factors, has a great influence on the performance of the split Stirling cooler. The viscous force and piston damping are affected by the assembly state of the displacer. The effects of the assembly state and friction coefficient of the piston on the performance of Stirling refrigerator were studied. The results show that the viscous force increases more quickly with smaller gap between piston and cylinder under coaxial state, but the viscous force is smaller. Under non-coaxial state, the viscous force of working medium on the displacer is almost unchanged when the eccentricity is less than 0.75, and it increases rapidly when the eccentricity reaches 0.99. The main source of resistance on displacer is from friction force, however, it has little effect on the performance of the split Stirling refrigerator at slight friction condition.