25). Investigations on a 3.3 K four-stage Stirling-type pulse tube cryocooler. Part A: Theoretical analyses and modeling. Cryogenics 105 (2020) 103014, https://doi.org/10.1016/j.cryogenics.2019.103014.

[Abstract]
This paper conducts systematic theoretical analyses of a four-stage SPTC aimed at directly reaching a tem perature of around 3 K and also simultaneously achieving the cooling capacities at four temperatures varying from 3.3 K to 80 K for multiple uses. The fourth stage cold finger is focused on and a 2-D axis-symmetric CFD model is set up to study the irreversible losses and phase characteristics. The operating mechanisms in the fourth stage are modelled, in which the distributions of the losses along the whole regenerator are analysed quanti tatively and the phase characteristics simulated as well. The interactions among the four stages are studied, in which the effect of parameters at each stage on the cooling performances of the other three stages is elaborated, respectively. The systematic optimization for the four-stage SPTC is then conducted. The detailed experimental verifications are presented in Part B.

Download Paper: PDF Document