Experimental study of effects of buffer tank volume on pressure pulsation in valved linear compressor's pipe system at different frequencies

不同频率下缓冲罐体积对有阀线性压缩机管系压力脉动的实验研究

¹ Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai 200083, China
² University of Chinese Academy of Sciences, Beijing 100049, China

Received: 3 April 2023

Abstract

The valved linear compressor (VLC) is an essential part of the Joule-Thompson (J-T) throttling cryocooler in the liquid helium temperature region. The pressure pulsation may cause the fluctuation of the temperature and cooling capacity of the cryocooler, thus affecting its temperature stability. To measure the pressure pulsation of the VLC's pipe system, the mathematical model of pressure pulsation in the buffer tank of the VLC was established with the transfer matrix method based on the plane wave theory. The quantitative representation of the pulsating mass flow of the VLC was obtained with the linear damping based on the plane wave theory. Then, a test bench was set up to measure the pressure pulsation. The influence of the VLC's operating frequency and the suction and discharge buffer tank volume on the pressure pulsation was discussed. Results show that the pressure pulsation of the pipe system is related to the VLC's operating frequency. The pressure pulsation of the pipe system increases with the increase of the VLC's operating frequency. Both the inlet and outlet buffer tanks can effectively inhibit the pressure pulsation, but their capability is independent of each other. The pressure pulsation inhibition effect is better with the increase of the buffer tank volume. With the increase of the buffer tank volume, the pressure inhomogeneity at the inlet of the inlet buffer tank decreases to 164 over 423, but the pressure inhomogeneity at the outlet of the outlet buffer tank decreases to 8 over 23.

摘要

有阀线性压缩机是液氦温区Joule-Thomson(J-T)节流制冷机重要部件, 而管系压力脉动会造成制冷机出现温度与制冷量波动, 从而影响制冷机温度稳定性。针对有阀线性压缩机管系压力脉动问题, 以有线性阻尼的平面波动理论为基础, 采用传递矩阵法构造了有阀线性压缩机管路缓冲罐压力脉动传递模型, 获得有阀线性压缩机脉动质量流量的量化表达。搭建了有阀线性压缩机管系压力脉动测试平台, 讨论了压缩机运行频率与进排气缓冲罐体积对压力脉动的影响。研究结果表明: 管系压力脉动与压缩机运行频率有关, 随着压缩机运行频率增大, 管系压力脉动增大。进排气缓冲罐均可有效抑制压力脉动, 但两者的压力脉动抑制能力相互独立, 且缓冲罐体积越大, 压力脉动抑制效果越好。随着缓冲罐体积的增加, 进气缓冲罐进口处压力不均匀度减小到164/423, 排气缓冲罐出口处压力不均度减小到8/23。