Prediction of temperature distribution in heat exchanger for mixed refrigerant Joule-Thomson cryocooler

The overall performance of a mixed refrigerant Joule-Thomson (MR J-T) cryocooler depends on the efficiency of the heat exchanger used to cool the refrigerant prior to J-T expansion. The multi-component refrigerant mixture gets condensed and evaporated simultaneously at different pressures in the recuperative heat exchanger which is responsible to increase its performance. However, at present, the design of such heat exchanger is difficult due to lack of experimental heat transfer data.

In the present paper, the temperature profile of the hot fluid condensing inside the inner tube of the tube-in-tube helical coil heat exchanger is predicted. The temperatures of both, the condensing and the evaporating stream are measured along the length of the heat exchanger. The energy balance equation is used to predict the temperatures of the hot fluid at the corresponding locations of the cold fluid temperature measurement. The calculated temperature profiles are compared against the experimentally obtained data for different mixtures. It is found that the predicted temperature profile matches well within ± 6 % limit for all the mixtures.