Title: Heat transfer characteristics of parallel and counter flow micro-channel heat exchangers with varying wall resistance

Authors: A.M. Maqableh, A.F. Khadrawi, M.A. Al-Nimr, S.A. Ammourah, A.C. Benim

Addresses: Mechanical Engineering Department, Al-Balqa' Applied University, Jordan. ' Mechanical Engineering Department, Al-Balqa' Applied University, Jordan. ' Mechanical Engineering Department, Jordan University of Science and Technology, Jordan. ' Mechanical Engineering Department, Philadelphia University, Jordan. ' Department of Mechanical and Process Engineering, Dusseldorf University of Applied Sciences, Dusseldorf, Germany

Abstract: Thermal behaviours of parallel and counter flow micro-heat exchanger are investigated numerically, with emphasis on the role of wall resistance and thermal entry effects. The influence of different parameters, such as, thermal resistance (R), Knudsen number (Kn), effectiveness (ε) and Number of Transfer Units (NTU) are investigated. It is found that the temperature jump at the walls increases with increasing R and Kn. On the other hand, the NTU increases with decreasing R and Kn. Furthermore, for counter flow, thermally fully developed flow may not exist over a large section of the heat exchanger due to the heat conduction in the separating wall and the entrance region.

Keywords: heat transfer; heat exchangers; microchannels; parallel flow; counter flow; numerical simulation; wall resistance; modelling.

DOI: 10.1504/PCFD.2011.042183

Progress in Computational Fluid Dynamics, An International Journal, 2011 Vol.11 No.5, pp.318 - 328

Published online: 31 Aug 2011 *

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