Design and optimization of coil finned-tube heat exchangers for cryogenic applications

Coiled finned-tube heat exchangers have been used in small and medium helium refrigerators/liquefiers, miniature J–T refrigeration systems for many years. The efficiency of these cryogenic systems strongly depends on the thermal and pressure drop performance of these heat exchangers. A considerable improvement in the performance of heat exchanger is possible by choosing an appropriate geometrical configuration for a given process requirement. In the present study, geometry of heat exchanger has been derived taking into consideration the clearance provided for manufacturing of the heat exchangers and an optimized geometrical configurations have been find out. The results show the possibility of adjusting the thermal and pressure drop performance by varying the clearance. The predictions of four end temperatures from present design method have been compared with the actual experimental results of one of the prototypes fabricated in our lab.