Numerical Analysis of a High Pressure Helical Coil
Tube in Tube Heat Exchanger for a Pulse Tube Refrigerator

Abstract

In the field of cryogenics heat exchangers always play an important role in bringing down the temperature or maintaining the temperature of a fluid. There are many types of heat exchangers being used worldwide for many different applications. One such application is the Pulse tube cryocooler. These pulse tube cryocoolers work on Stirling cycle and can bring the temperature down to 4K with the proper equipment and they are bound to have a heat exchanger at one of the pulse tube ends. Generally, a shell and tube heat exchangers are used because of it availability in the market but a helical coiled heat exchanger can be more effective in terms of heat transfer and space occupied. The only downside of this heat exchanger is that it needs to be manufactured specifically and is not the readily available in the market as a shell and tube heat exchanger. This work focusses on designing a heat exchanger for the hot end of a pulse tube refrigerator. A helical tube in tube design is selected and simulations for various velocities of the working fluid in a pulse tube have been carried out and results were derived from the simulations. The size of the pipe used are the standard 0.25-inch, 0.375 inch and 0.5 inch. The results have been compared and the best size of the Heat exchanger to be used is determined based on the results from the simulations.