Leveraging Real Fluid Effects as a Tool for Power Flow Measurements in 4 K Cryocooler Regenerators

Published

April 1, 2021

Author(s)

Ryan Snodgrass, Vincent Y. Kotsubo, Joel Ullom, Scott Backhaus

Abstract

The real fluid properties of helium have a major impact on the thermodynamics of pulse tube and Gifford-McMahon cryocoolers operating below about 30 K. For example, real fluid properties cause the temperature profile in low-temperature regenerator to be nearly constant at the cold end and allow heat to be applied at warmer, intermediate points along the regenerator axis without affecting cooling power at the cold heat exchanger. We leverage these unique properties and the injection of intermediate heat as a tool for probing and validating the total power equation. As an initial demonstration of this technique, we show how it can be used to measure steady mass flow through the regenerator. We also discuss and demonstrate more advanced measurement protocols that may be used to isolate other terms responsible for power flow in low-temperature regenerators.

Proceedings Title

Cryocoolers 21

Conference Dates

December 7-10, 2020

Conference Location

N/A (virtual), CO, US

Conference Title

21st International Cryocooler Conference

Pub Type

Conferences

Download Paper

Local Download

Keywords

Cryocoolers, pulse tube refrigerator, thermodynamics

Citation

Snodgrass, R. , Kotsubo, V. , Ullom, J. and Backhaus, S. (2021), Leveraging Real Fluid Effects as a Tool for Power Flow Measurements in 4 K Cryocooler Regenerators, Cryocoolers 21, N/A (virtual), CO, US, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=931619 (Accessed October 20, 2025)