Heat transfer and pressure drop in a channel with multiple 60° V-baffles

The research work has been conducted to assess turbulent forced convection heat transfer and friction loss behaviors for airflow through a channel fitted with a multiple 60 degrees V-baffle turbulator. Measurements have been carried out for the channel of aspect ratio, AR=10 and height, H=30 mm with three different baffle blockage ratios, (e/H=0.10, 020 and 030) and three baffle pitch spacing ratios, (PR = P/H = 1, 2 and 3) while the transverse pitch of the V-baffle is set to 2H and kept constant. The air flow rate is in terms of Reynolds numbers based on the inlet hydraulic diameter of the test channel ranging from 5000 to 25,000. The experimental results show that the V-baffle provides the drastic increase in Nusselt number, friction factor and thermal enhancement factor values over the smooth wall channel due to better flow mixing from the formation of secondary flows induced by vortex flows generated by the V-baffle. In addition, substantial increases in Nusselt number and friction factor values are found for the rise in blockage ratio and/or for the decrease in pitch ratio values. Assessing thermal performance of the V-baffled channel, the use of the V-baffle with PR=1 and e/H=0.10 leads to maximum thermal enhancement factor of about 1.87 at lower Reynolds number. (C) 2010 Elsevier Ltd. All rights reserved.