NUMERICAL STUDY ON FLOW AND HEAT TRANSFER PERFORMANCE OF A NOVEL MULTILAYER MINI-CHANNEL HEAT EXCHANGER WITH LOW AXIAL HEAT CONDUCTION

Abstract

The printed circuit heat exchanger is a typical representative of mini-channel heat exchangers, which are generally applied in many advanced energy and power systems due to their high compactness and efficiency. However, axial heat conduction may significantly decrease efficiency at low mass flow rates, and few studies have focused on enhancing the performance of heat exchangers by reducing axial heat conduction. This study proposes a novel multilayer mini-channel heat exchanger to solve this problem. The axial heat conduction of the new design is reduced by inserting phlogopite layers into the metal sections. The thermal-hydraulic performance of the novel multilayer mini-channel heat exchanger is investigated at different numbers of segments and different mass flow rates using Fluent. The results show that, at low mass flow rate, the performance of the multilayer heat exchanger is superior to that of a traditional heat exchanger. With the increase of heat exchanger segments, the performance of the multilayer heat exchanger is improved. The maximum relative increment in the new heat exchanger efficiency is 1.6%, and the pressure drop is relatively reduced by 12.3%. The difference in performance between the multilayer heat exchanger and the traditional heat exchanger decreases when increasing the mass flow rate. It is recommended that more segments of multilayer heat exchanger should be used for lower mass flow rates to achieve better performance.