Thermal hydraulic performance and characteristics of a microchannel heat exchanger: experimental and numerical investigations

Abstract

This paper presents extensive fluid flow and Heat Transfer studies conducted through an experimental setup followed by a detailed three-dimensional (3D) numerical analysis of the same setup using a commercial package for computational fluid dynamics (CFD), known as cfd-ace® for additive-manufactured counterflow AlSi10 Mg microchannel heat exchangers (MCHEs). A detailed 3D computational model of the experimentally tested MCHEs was built and analyzed using the commercial software cfd-ace® for the same experimentally tested operating conditions. The computational model results are in good agreement with experimental data of tested MCHE within +2% to +7% and ∼0% to −13.5% variation for cold and hot fluids for the entire set of design of experiments (DoEs). This percentage disagreement may be due to various factors, such as manufacturing deviation within tolerance, longitudinal conduction, variation in the thermal conductivity of the material after heat treatment, variation in environmental temperature, sensor deviation, and surface roughness of internal channels. Instead of Stainless steel (SST), AlSi10 Mg was used because of its lower manufacturing cost because AlSi10 Mg was lighter than SST, though its thermal conductivity is almost ∼8–10 times more than that of SST. A higher thermal conductivity is not good for MCHEs because it leads to higher longitudinal conduction, which eventually degrades the performance of MCHEs in terms of effectiveness. MCHE effectiveness is also reduced by ∼12% to 18% owing to longitudinal conduction from ideal effectiveness.