Experimental investigation of axial pressure drop analysis on the additively manufactured porous regenerator

Abstract

Regenerators are used in cryogenics for nitrogen and helium liquefaction through reversed Stirling cycle to achieve a low operating temperature of 40 K. An ideal regenerator has critical properties such as low thermal conductivity, optimum porosity, high heat transfer, and specific heat. In general, the matrix of the porous materials is in the form of wire mesh, fibrous wool, granules, or foams. The recent technological development in additive manufacturing (AM) allows it to extend its application to porous structure-based energy exchanging devices. Direct metal laser sintering (DMLS) is one of the AM processes used to fabricate complex geometry with uniform porosity, of considerably low cost compared with the conventional processes. This paper presents the development of an experimental setup to investigate the steady axial pressure drop analysis through various types of regenerators. These regenerators have been tested for multiple working fluids such as Argon and Helium gas at room temperature. The axial pressure drop results of the additive regenerator have been compared with the woven wire mesh and copper wool type of regenerators. The additively manufactured regenerator has a lower pressure drop of 9% and 14% than the copper wool and woven wire mesh type regenerators.