Sterling Cryocooler test results And Design Model Verification

This paper reports on progress in developing a long-life Stirling cycle cryocooler for spaceborne applications. It presents the results from tests on a preliminary "breadboard" version of the cryocoolor used to demonstrate the feasibility of the technology and to validate the regenerator design code used in its development. This machine achieved a cold-end temperature of 65 K while carrying a 1/2 Watt cooling load. The basic machine is a double-acting, flexure-bearing, split Stirling design with linear electromagnetic drives for the expander and compressors. Flat metal diaphragms replace pistons for both sweeping and scaling the machine working volumes. In addition, the double-acting expander couples to a laminar-channel counterflow recuperative heat exchanger for regeneration. A PC compatible design code was developed for this design approach that calculates regenerator loss including heat transfer irreversibilities, pressure drop, and axial conduction in the regenerator walls. The code accurately predicted cooler perf6rinance and assisted in diagnosing breadboard machine flaws during shakedown and development testing.