Studies on the development and efficiency improvement of a 1.5 W at 25 K two stage pulse tube cooler

26th International Cryogenic Engineering Conference & International Cryogenic Materials Conference 2016

材料科学;物理学

Kranthi Kumar, J.^1 ; Jacob, S.^1 ; Karunanithi, R.^1 ; Narasimham, G.S.V.L.^2

Center for Cryogenic Technology, Indian Institute of Science, Bengaluru

560012, India^1

Dept. of Mechanical Engineering, Indian Institute of Science, Bengaluru

560012, India^2

关键词: Efficiency improvement;    Experimental investigations;    Filling pressures;    Flow distribution;    High frequency HF;    Phase relationships;    Pressure wave generators;    Pulse tube coolers;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/171/1/012068/pdf
DOI  :  10.1088/1757-899X/171/1/012068

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

A high frequency two stage pulse tube cooler (PTC) has been designed using Sage software for a JT-PTC hybrid helium recondensation system. The cold end of the first stage regenerator is anchored at 80 K using a liquid nitrogen supply. Such a thermally coupled design simplifies the design without the need for considering flow distribution between the stages and ensures that entire flow is available to produce cooling power at 25 K. The pulse tube cooler is designed for maximal utilization of the 900 W PV power provided by the Pressure Wave Generator (PWG). With the first prototype, a no load temperature of 40.4 K was achieved at a filling pressure of 24.1 bar. The effect of filling pressure on the acoustic matching of the PTC and PWG was investigated. It is observed that filling pressure has a significant effect on the PWG piston stroke amplitude. Using phasor analysis, it is shown that the phase relationship at different sections of the two stage PTC is detrimentally affected by the pulse tube volume. A scheme for achieving advantageous phasing by reducing the pulse tube volume is proposed. This involves maintaining the hot heat exchanger, inertance tube and buffer volume at 80 K. With the modification it is shown that a beneficial phase reversal across second stage Regenerator is achieved. The method is currently under experimental investigation.