Thermoacoustic Modeling of Cryogenic Hydrogen

Abstract

Future thermoacoustic cryocoolers employing hydrogen as a working fluid can reduce reliance on helium and improve hydrogen liquefaction processes. Traditional thermoacoustic modeling methods often assume ideal-gas thermophysical properties and neglect finite-amplitude effects. However, these assumptions are no longer valid for hydrogen near saturated states. In this study, a comparison between the results of computational fluid dynamics simulations using actual hydrogen properties and a low-amplitude, ideal-gas thermoacoustic theory was carried out in a canonical plate-based stack configuration at a mean pressure of 5 bar. It was found that the simplified analytical theory significantly underpredicts the cooling power of hydrogen-filled thermoacoustic setups, especially at lower temperatures in high-amplitude, traveling-wave arrangements. In addition, a thermoacoustic prime mover was modeled at higher temperatures, demonstrating very close agreement with the ideal-gas-based theory. The CFD approach is recommended for the design of future hydrogen-based cryocoolers at temperatures below 80 K.

Keywords

• thermoacoustics
• computational fluid dynamics
• cryogenics
• hydrogen