气体分配器结构对压力波制冷机内流动及性能的影响

摘要

The influence of some structural factors,i. e. the nozzle style,relative gas charge time on the flow in and the performance of pressure wave refrigerator are studied theoretically and experimentally in this paper. The results show that the strength of incident shock wave is the strongest when using the contraction nozzle,follows by using the laval nozzle,and is the weakest when using the uniform noz-zle when the ratio of the expansionεis from 2. 0 to 12. 0. Thus the cooling effect of pressure wave refrigerator is the strongest when using the contraction nozzle. The maximun refrigerating efficiencyηmax is increased first and then decreased when the relative gas charge timeτis increased. The optimum relative gas charge time τ is about 0. 06 when the ratio of the expansionεis 4,the ratio of length to diameter L/d is 400 and the relative depth of the jet hole in gas distribution is 0. 55. Whenτ>0. 075,the optimum pulsing frequency (fopt) is on the second peak of the refrigerating efficiency ,while fopt is on the third peak of the refrigerating efficiency when τ>0. 075.%采用理论分析和实验研究相结合的方法，探讨了喷管型式、相对充气时间等气体分配器结构因素对压力波制冷机内流动及性能的影响。结果表明：膨胀比ε在2.0~12.0的范围内，采用收缩型喷管形成的入射激波最强，缩放型喷管次之，匀直喷管最弱，因而采用收缩型喷管时的冷效应最强；最大制冷效率ηmax随相对充气时间τ的增加先增大后减小，在ε＝4、振荡管长径比L/d＝400、气体分配器喷射孔的相对深度为0.55的情况下，制冷机最佳相对充气时间约为0.06；相对充气时间τ<0.075时，振荡管的最佳激励频率fopt为制冷效率曲线第二波峰的频率，τ>0.075时则为制冷效率曲线第三波峰的频率。