The acoustic field of a linear compressor serves to deliver the compression work to the load, such as the connected cold head of a cryocooler; it plays an equivalently important role as the electrical and mechanical parts, especially in the impedance match issue. This paper studies the acoustic impedance characteristics of a linear compressor. The parameters including the current, the piston displacement, the pressure amplitude, the electrical power dissipation, the power factor, the pressure-volumetric (PV) power delivered, and the efficiency are theoretically and experimentally investigated. Different from previous theoretical studies, optimization for the operations away from the resonance is also included. More general optimization results imply relevance between thermoacoustic engines and linear compressors. The predicted results are validated by the experiments performed on a linear compressor with an adjustable resistive-capacitive (RC) acoustic load. The comparisons between the calculations and the measurements are presented and analyzed. The results provide deeper insight into the mechanism of the linear compressor and the impedance match in a cryocooler system.
经过多次调整,计划将于2018年发射的詹姆斯·韦伯太空望远镜(James Webb Space Telescope,简称JWST)中的中红外仪(Mid-Infrared Instrument,简称MIRI)低温制冷系统最终选用三级脉管制冷机预冷J-T(Joule-Thomson)循环的复合型低温制冷技术。详细介绍了该技术的发展历程,表明该复合型低温制冷技术已在空间任务中逐渐替代固氢或液氦杜瓦技术,以期为国家未来空间计划的实施提供借鉴。
