Steady state numerical analysis of a Joule-Thompson cryocooler for cryosurgical probe

The Hampson-type Joule-Thomson cryocoolers are preferred for cryosurgical probes due to their small size and no moving parts. Due to substantial change of pressure and temperature along both the inlet and returning streams, property variations of the working fluid and pressure drop in the streams have to be realistically accounted for. Numerical analysis is the key to such demanding design applications. In the present work, steady state numerical simulation of the heat exchanger of the Joule- Thomson cryocooler is carried out. The model predicts the pressure and temperature profiles of the high pressure inlet and low pressure returning stream. These results are validated using various data available in literature. Once validated, the steady state model may be used for design of heat exchanger for Joule-Thompson cryocooler to be used in cryosurgical probe. Various key parameters of the heat exchanger that affect its performance are identified and their effects are studied.