Experimental study on laminar pulsating flow and heat transfer of nanofluids in micro-fins tube with magnetic fields

A combined heat transfer enhancement techniques: pulsating flow, nanofluids, micro-fins tube, and magnetic field on the heat transfer and flow characteristics in the micro-fins tube are investigated. Experiments are performed under conditions of nanofluids Reynolds number varying from 1000 to 2400 and nanofluids concentrations of 0.25%, 0.50% by volume. The inlet nanofluids and uniform wall heat input are 20 degrees C, and 120-160 W, respectively while the nanofluids frequency pulsating flow through the test section is 10-20 Hz. The results obtained from the micro-fins tube with magnetic field are compared with those without magnetic field and those from the smooth tube with and without magnetic fields. It can be seen that a combined heat transfer enhancement techniques are a good potential to improve the thermal performance of thermal devices. The pulsating flow and magnetic field have an advantage on the Brownian motion of nanoparticles in the base fluid flowing through the system. Results show that the heat transfer enhancement increases significantly with increase in nanoparticle concentration, magnetic field strength, and with the pulsating frequency. However, they are slightly effect on the pressure drop. (C) 2017 Elsevier Ltd. All rights reserved.