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

Kranthi Kumar, J and Jacob, S and Karunanithi, R and Narasimham, G S V L (2017) Studies on the development and efficiency improvement of a 1.5 W at 25 K two stage pulse tube cooler. In: 26th International Cryogenic Engineering Conference / International Cryogenic Materials Conference, MAR 07-11, 2016, Indian Cryogen Council, New Delhi, INDIA.

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Abstract

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.

Item Type:	Conference Proceedings
Series.:	IOP Conference Series-Materials Science and Engineering
Publisher:	IOP PUBLISHING LTD, DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND
Additional Information:	Copy right for this article belongs to the IOP PUBLISHING LTD, DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering Division of Physical & Mathematical Sciences > Centre for Cryogenic Technology
Date Deposited:	20 May 2017 07:19
Last Modified:	20 May 2017 07:19
URI:	http://eprints.iisc.ac.in/id/eprint/56967

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