Calculated Performance of Low-Porosity Regenerators at 4 K with He-4 and He-3
Ray Radebaugh, Yonghua Huang, Agnes A. O'Gallagher, John M. Gary
Previously we have shown that the lower volumetric heat capacity and more ideal behavior of helium-3 compared with helium-4 at 4 K results in an improved performance for packed sphere regenerators operating with helium-3 between 4 K and about 20 K. In this paper we use the NIST numerical software REGEN3.3 to calculate the regenerator loss and the coefficient of performance (COP) of 4 K regenerators with porosities between 0.1 and 0.38 for parallel holes in a rare-earth matrix operating at 30 Hz frequency using either helium-3 or helium-4. A comparison is made with packed spheres at a porosity of 0.38. Calculations were made for average pressures ranging from 0.3 MPa to 1.5 MPa, mostly with a pressure ratio of 1.5. The results show that the regenerator loss decreases and the COP increases as the porosity decreases for all average pressures. For helium-3 the regenerator performance is improved for pressures below 1 MPa, whereas the lower pressures do not benefit helium-4 regenerators. The COP of a helium-3 regenerator with 0.2 porosity operating at 30 Hz and 0.5 MPa average pressure is about 3.8 times higher than a helium-4 regenerator using packed spheres with 0.38 porosity. The effect of regenerator matrix material and the temperature of the heat capacity peak are also investigated.
, Huang, Y.
, O'Gallagher, A.
and Gary, J.
Calculated Performance of Low-Porosity Regenerators at 4 K with He-4 and He-3, ICC Press, Boulder, CO, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=832365
(Accessed December 10, 2023)