Effect of Component Geometry on Flow Nonuniformities in a Large Pulse Tube Cryocooler

Published

May 17, 2010

Author(s)

Michael A. Lewis, Ryan P. Taylor, Ray Radebaugh, Peter E. Bradley

Abstract

A single-stage pulse tube cryocooler was designed to achieve 50 W of refrigeration power at 50 K when driven by a pressure oscillator that can produce up to 2.8 kW of acoustic power at 60 Hz. Initial experimental data produced no-load temperatures that were considerably higher than expected. Improvements were made with the warm end heat exchanger and aftercooler and diffusion bonding of the copper screen matrix materials which produces significant improvements to the low end temperatures. The primary diagnostic tools utilized were four equidistant azimuthally spaced thermocouples located at the aftercooler exit, center plane of the regenerator component, and center plane of the pulse tube component. These tools provided temperature distribution information throughout the system and how specific geometry changes throughout the pulse tube cryocooler would affect overall performance. This paper address specific geometry changes to several major components of the cryocooler and their effect on the cryocooler performance. These include the transition piece from the inertance tube where the helium gas is entering and exiting the warm end heat exchanger and pulse tube. Pulse tubes with various aspect ratios are tested to find the optimum aspect ratio. A major modification to the cold end heat exchanger matrix design will be implemented for more uniform gas flow through the diffusion bonded copper screen stacks. The effect of interspersing various amounts of copper screen along the stainless steel regenerator packing is also investigated.

Conference Dates

May 17-21, 2010

Conference Location

Atlanta, GA

Conference Title

16th International Cryocooler Conference

Pub Type

Conferences

Keywords

aftercooler, aspect ratio, cryocooler, heat exchangers, nonuniformity, pulse tube

Citation

Lewis, M. , Taylor, R. , Radebaugh, R. and Bradley, P. (2010), Effect of Component Geometry on Flow Nonuniformities in a Large Pulse Tube Cryocooler, 16th International Cryocooler Conference, Atlanta, GA (Accessed November 30, 2024)