Plate Fin Heat Exchanger Model with Axial Conduction and Variable Properties

TL;DR

This paper develops a numerical model for plate-fin heat exchangers operating at cryogenic temperatures, incorporating axial conduction and variable fluid properties to optimize design and analyze Joule-Thomson expansion effects.

Contribution

It introduces a comprehensive numerical model that accounts for axial conduction and variable properties, aiding the design of cryogenic heat exchangers for superfluid helium cooling.

Findings

Model guides material and geometry choices.

Analyzes heat load effects on J-T expansion.

Supports efficient cryogenic system design.

Abstract

Future superconducting radio frequency (SRF) cavities, as part of Project X at Fermilab, will be cooled to superfluid helium temperatures by a cryogenic distribution system supplying cold supercritical helium. To reduce vapor fraction during the final Joule-Thomson (J-T) expansion into the superfluid helium cooling bath, counter-flow, plate-fin heat exchangers will be utilized. Due to their compact size and ease of fabrication, plate-fin heat exchangers are an effective option. However, the design of compact and high-effectiveness cryogenic heat exchangers operating at liquid helium temperatures requires consideration of axial heat conduction along the direction of flow, in addition to variable fluid properties. Here we present a numerical model that includes the effects of axial conduction and variable properties for a plate fin heat exchanger. The model is used to guide design decisions on heat exchanger material choice and geometry. In addition, the J-T expansion process is modeled with the heat exchanger to analyze the effect of heat load and cryogenic supply parameters.