ABSTRACT
This chapter examines the design principles for heat exchangers that are commonly used for cryogenic service. One of the critical components of many cryogenic systems, such as liquefiers and cryocoolers, is the heat exchanger. A unique extended-surface heat exchanger design involving flow in concentric tubes was developed by Prof. The ribbon helix acted as a fin to increase the heat transfer surface area of the exchanger. These heat exchangers have been manufactured with as many as 10 separate flow passages. Plate-fin heat exchangers consist of stacks of alternate layers of corrugated die-formed metal sheets separated by flat metal separation sheets. The calculations for the pressure drop for the helium and nitrogen streams are similar; therefore, the calculations will be presented in parallel, as was done for the heat transfer coefficients. Finally, the heat exchanger effectiveness gives a direct measure of the influence of the heat exchanger performance on the cryogenic system performance.
