You are here : Home > The DSBT > Next step towards the miniaturisation of space cryocoolers

Arkadii Sochinskii

Next step towards the miniaturisation of space cryocoolers

Published on 26 October 2018
Thesis presented October 26, 2018

This research is done in the framework of miniaturisation of pulse tube cryocoolers studies and especially to gain a better understanding of the mass flow and heat transfert in the regenerator, which is a crucial component of these type of cryocoolers.
In this work we present a numerical and experimental study of the Darcy-Weisbach friction factor and Nusselt number for a continuous and steady flow at moderate Reynolds number O(1−100) in a micro-machined regenerators. The influence of porosity from 40 to 80 % and of the geometry parameters are studied. Well-controlled microstructures represent convoluted channels of 10, 20 or 40 μm width and 100 or 300 μm depth generated by rhombic- or sinusoidal-shaped columns. The channels are etched in Silicon wafers using DRIE MEMS technology. The thermometers are integrated inside the regenerator’s micro-structure to measure the temperature evolution. The efficiency of the regenerators is estimated using two different approaches: the first, as a ratio of pressure drop losses and heat transfer efficiency (NPH/NTU); the second, as a volumetric heat transfer density coefficient proposed by Bejan. The numerical study of the efficiency shows the interest of proposed micro-structures.

Regenerator, MEMS, Friction factor, Nusselt number, DRIE, Pulse tube

On-line thesis.