Development and Testing of a Multi-Plate Recuperative Heat Exchanger for Use in a Hybrid Cryocooler
D. Hoch1, G. Nellis2, N. Meagher1, J. Maddocks3, S. Stephens4
1Univ. of Wisconsin, Madison, WI, 2University of Wisconsin-Madison, Madison, WI, USA, 53706, 3Atlas Scientific, San Jose, CA, 4AFRL, Kirtland AFB, NM
AbstractCurrent available cryocooler technology operating at sub-10 K load temperatures is too massive and inefficient to be considered for future space-based systems. High vibrations and low reliability often cause these systems to limit the operating life relative to what is required of space flight hardware. A compact and innovative hybrid cryocooler is being developed that has the potential to provide a more efficient means of cooling future space-based systems . The cooler directly interfaces a recuperative, reverse-Brayton, low-temperature stage with a regenerative, pulse-tube upper stage .
Four components of the PT/RB are critical to its performance: the pulse-tube cold head, the rectification system, the cryogenic turbine and the high effectiveness recuperative heat exchanger. The focus of this paper will be on the recuperative heat exchanger, which uses chemically etched copper plates interleaved with stainless steel axial conduction barriers. A model of the recuperative heat exchanger is described; the model is used to optimize the geometry subject to constraints associated with fabrication and mass. A sub-scale module has been fabricated in order to verify the model and develop the fabrication techniques. The experimentally measured ineffectiveness of the sub-scale module agrees with the model predictions. Based on the success of the sub-scale module and using the verified heat exchanger model, two full-scale modules have been fabricated, assembled and tested at the component level. The performance of the full-scale modules is compared with the model prediction.