The effectiveness-NTU relationship of microchannel counter flow heat exchangers with axial heat conduction

B. Mathew, H. Hegab

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Citations (Scopus)

Abstract

In this paper the effect of axial heat conduction on the thermal performance of a microchannel heat exchanger with non-adiabatic end walls is studied. The two ends of the wall separating the coolant are assumed to be subjected to boundary condition of the first kind. As the end walls are not insulated heat transfer between the microchannel heat exchanger and its surroundings occur. Analytical equations have been formulated for predicting the axial temperature of the coolants and the wall as well as for determining the effectiveness of both fluids. The effectiveness of the fluids has been found to depend on the NTU, axial heat conduction parameter and end wall temperatures. The heat transfer through the end walls have been expressed in nondimensional terms. The nondimensional heat transfer from both ends of the wall also depends on the axial heat conduction parameter and temperature gradient at the end walls. A new parameter, performance factor, has been proposed for comparing the variation in effectiveness due to axial heat conduction coupled with heat transfer with the effectiveness without axial heat conduction. The effectiveness of both the hot and cold fluid for several cases of end wall temperatures and axial heat conduction parameter are analyzed in this paper for better understanding of heat transfer dynamics of microchannel heat exchangers.

Original languageEnglish
Title of host publicationProceedings of the ASME International Mechanical Engineering Congress and Exposition, IMECE 2007
Pages527-536
Number of pages10
DOIs
Publication statusPublished - 2008
Externally publishedYes
EventASME International Mechanical Engineering Congress and Exposition, IMECE 2007 - Seattle, WA, United States
Duration: Nov 11 2007Nov 15 2007

Publication series

NameASME International Mechanical Engineering Congress and Exposition, Proceedings
Volume8 PART A

Other

OtherASME International Mechanical Engineering Congress and Exposition, IMECE 2007
Country/TerritoryUnited States
CitySeattle, WA
Period11/11/0711/15/07

Keywords

  • Axial heat conduction
  • Effectiveness
  • Heat exchanger
  • Microchannels
  • NTU

ASJC Scopus subject areas

  • General Engineering
  • Mechanical Engineering

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