Evaporation heat transfer coefficient and pressure drop of n-pentane inside parallel multiport mini channel

Abstract

This paper investigates experimentally heat transfer during evaporation of n-pentane inside a parallel multiport mini-channel. The experimental tests are conducted in a test section within five rectangular stainless steel minichannels. The local heat transfer coefficient is measured for different testing conditions to study the influence of mass flux (G = 113–187 kg/m2·s) and heat flux (200 W–320 W). For low vapor quality region [0–0.4], the domination of nucleate boiling is significant while the forced convective boiling is obtained for high vapor quality region. A comparison of the experimental results with existing correlations is carried out by calculating mean absolute deviation which led to some diverging correlations >100% while others present a good estimation around 30%. Thus, a new correlation is developed to predict local heat transfer with MAE of 22% based on the experimental results. A considerable attention is also paid to pressure drop effects by measuring experimentally pressure drop in the minichannels and develop a new correlation to evaluate frictional pressure drop.