液氦温区VM-PT制冷机气量分配特性

摘要

VM气耦合脉冲管制冷机(VM-PT)是一种新型的液氦温区制冷机,为探索两级气耦合复杂的机理,本文采用Sage软件构建了低温调相VM-PT制冷机的整机模拟程序,研究了运行频率、平均压力、毛细管长度以及Er3Ni填充长度等参数对两级气量分配的影响.结果表明:运行频率、平均压力、毛细管长度以及Er3Ni填充长度均会影响两级质量流的分配,进而影响制冷机的最低温度,权衡工质的做工能力以及蓄冷器损失两方面因素,该四个参数均存在一个最佳值.搭建了实验平台并对数值模拟进行了验证.在实验中通过优化毛细管和蓄冷器,在运行频率1.6 Hz、平均压力1.4 MPa、压比1.6的情况下得到了3.86 K的无负荷制冷温度,在4.2K可提供约10 mW的制冷量.%Vuilleumier gas-coupling pulse tube cryocooler (VM-PT) is a novel kind of cryocooler capable of attaining liquid helium temperature.For investigating on the complex mechanism of gas distribution between two stages,a numerical model of VM-PT cryocooler was built by using Sage software.The influence of the operating frequency,the average pressure,the length of capillary tube and the filling length of Er3Ni on the distribution characteristics of mass flow were studied respectively.The results showed that those four parameters would change the gas distribution between two stages and then influence the coldest temperature of VM-PT cryocooler.By weighing the cooling capacity of working gas and the losses of regenerator,those parameters had its optimal value for the performance of cryocooler.Then,an experimental bench was built to verify the results of simulation.By optimizing the parameters of capillary tube and the filling method of a cold regenerator,a no-load temperature of 3.86 K was obtained in the experiment and the cooling capacity at 4.2 K was demonstrated to be about 10 mW.