Experimental investigation of shell side heat transfer and pressure drop in a mini-channel shell and tube heat exchanger

Abstract

This study experimentally investigated the shell side heat transfer and pressure drop of a mini-channel shell and tube heat exchanger (MC-STHE) designed and manufactured using Kern's method. A shell with an inner diameter of 30 mm and four horizontally oriented transverse baffles with a 25% baffle cut were used in the mini-channel heat exchanger. Using rotated triangular layout, the tube bundle was composed of 13 mini-channel copper tubes with an outer diameter of 3 mm and a length of 240 mm. The shell-side Reynolds numbers ranged from 250 to 2500 while the tube-side Reynolds number was kept constant at ∼5900 based on the experimental surface flow area goodness factor (j/f) results. The shell side convective heat transfer coefficients and total pressure drop results were compared with correlations for macro tubes commonly used in the literature. The experimental convective heat transfer coefficients were in good agreement with the Kern design, VDI-HA and McAdam’s correlations within the Reynolds numbers ranging from 250 to 2500. The experimental total pressure drop of the MC-STHE was 2.3 times higher than that of macro tube heat exchangers. In addition, the Nusselt number and Colburn factor correlations were proposed for the estimation of shell side convective heat transfer coefficient in MC-STHEs. The optimum working range for shell side is Re < 1000 according to surface flow area goodness factor by which heat transfer and hydrodynamic effects in MC-STHE are evaluated together.