An Experimental Investigation of R134a Flow Distribution in Horizontal Microchannel Manifolds

摘要

This project aims to find correlations between various flow parameters and liquid refrigerant flowdistribution within a horizontal manifold supplying two-phase R134a downward into fifteen aluminummicrochannels. Liquid flow rates, system pressures, and refrigerant temperatures are recorded. Prior to this project,similar experiments were conducted using an identical manifold setup with water/air as the working fluid.Similarities and differences between the two working fluids are discussed. During refrigerant testing, inlet flowrates are varied between 15 g/s and 35 g/s. Inlet qualities vary between 0% and 35%. Manifold flow path geometryis varied by using three spacer plates of different thickness. Increasing mass flux at the entrance of the manifoldimproves liquid distribution through the microchannels. At sufficiently high mass fluxes, increasing quality at theentrance also improves liquid distribution. The distance between the manifold inlet and the array of microchanneltubes also has a large effect on liquid distribution.