Entropy generation analysis of a mini heat exchanger for heat transfer intensification

Abstract

This paper presents a first and second law analysis of the heat transfer characteristics of a mini shell-and-tube heat exchanger equipped with multi-scale distributor/collector. Experiments of heat exchanger with or without transverse baffles installed in the shell side are conducted, under laminar flow conditions (average channel Re number between 8 and 100). The temperature field at the shell side is obtained by using infrared thermography. The effects of transverse baffles on the thermal performance and entropy generation of the heat exchanger system are quantified and discussed. Experimental results show that the integration of multi-scale branched distributor and collector guarantees uniform flow distribution among parallel tubes. The installation of baffles provides a locally crossflow and globally countercurrent flow arrangement so that the recirculating, passive zones can be largely eliminated. Enhancement of heat transfer has been verified by first law (global heat transfer coefficient) and second law (entropy generation) analyses.