Abstract
In this paper the effect of surface roughness on the performance of counter flow microchannel heat exchanger has been numerically investigated. The studied Microchannel heat exchanger is a square shape and made of aluminum as substrate material with different values of hydraulic diameters (20, 50, 110, 150 ) μm. The working fluid used is water at constant properties. Roughness- viscosity model has been used to study the roughness effect with 0.14 ratio of roughness to hydraulic diameter. The results obtained indicate that pressure drop of (CFMCHX) increased with increasing surface roughness and decrease hydraulic diameter also the results showed that there is a slight increasing in thermal performance with increasing the surface roughness.
