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Surface radiative transfer in gas‐to‐gas cocurrent microheat exchanger
Author(s) -
Mahulikar Shripad P.,
Herwig Heinz,
Zhou JingWei,
Sodhani Yash M.
Publication year - 2011
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.12250
Subject(s) - convective heat transfer , heat transfer coefficient , heat transfer , plate heat exchanger , heat exchanger , thermodynamics , micro heat exchanger , dynamic scraped surface heat exchanger , mechanics , plate fin heat exchanger , heat spreader , convection , ntu method , concentric tube heat exchanger , radiative transfer , materials science , chemistry , critical heat flux , optics , physics
Abstract The influence of surface radiative transfer in parallel flow microheat exchanger is numerically studied for its importance at high temperatures and for small flow dimensions. For these heat exchangers, the role of radiation is beneficial when the convective heat transfer to the annulus flow exceeds the convective heat transfer from the core flow. For this case, radiation improves the heat exchanger performance by decreasing the logarithmic mean temperature difference and by increasing the capacity, effectiveness, and volumetric heat transfer coefficient. Additional surface area is made available for convection to the annulus flow, thereby increasing the specific heat transfer surface for fixed geometry. Therefore, a high emissivity layer over the surfaces of microheat exchanger can improve the heat exchange performance. The active heat transfer area weighted by the convective heat flow rates is introduced as the true measure of heat exchanger compactness. © 2010 American Institute of Chemical Engineers AIChE J, 2011