Performance analysis of coiled finned tube heat exchanger for medium size helium liquefier

In this work, a numerical model has been developed for theoretical analysis of coiled heat exchanger in the temperature range of 77 K - 300 K. The numerical model is validated with the experimental data available in the literature. The objective of this study is to design and optimize the heat exchanger to achieve the desired effectiveness and therefore, the drop in the temperature of the hot gas. Numerical simulations have been carried out by varying the geometrical parameters like fin density, coil diameter, etc., and operating parameters like pressure and mass flow rate. It is observed that mass flow rate in the range of 2–2.5 g/s results in heat exchanger effectiveness of more than 0.95 for a charging pressure range of 11–15 bar. For different mass flow rates, the minimum requirement of the product UA for achieving effectiveness values greater than 0.95 is also mentioned.