EXPERIMENTAL VALIDATION OF LMTD METHOD FOR MICROSCALE HEAT TRANSFER

Year 2017, Volume: 3 Issue: 2, 1181 - 1195, 01.04.2017

Nezaket Parlak

https://doi.org/10.18186/thermal.298619

Cited By: 1

Abstract

The single phase fluid flow and heat
transfer characteristic has been investigated experimentally. Experiments were
conducted to cover transition zone for the Reynolds numbers ranging from 100 to
4800 by fused silica and stainless steel microtubes having diameters of 103-180
µm. The applicability of the Logarithmic Mean Temperature Difference (LMTD)
method was revealed and an experimental method was developed to calculate the
heat transfer coefficient. Moreover the scaling effects in micro scale such as
axial conduction, viscous heating and entrance effects were discussed. The heat
transfer coefficients were compared with data obtained by the correlations
available in the literature in the study. The Nusselt numbers of microtube
flows do not accord with the conventional results when the Reynolds number was
lower than 1000. After that, the Nusselt number approaches the conventional
theory prediction. On the aspect of fluid characteristics, the friction factor
was well predicted with conventional theory and the conventional friction
prediction was valid for water flow through microtube with a relative surface
roughness less than about 4 %.

Keywords

Microscale flow and heat transfer, LMTD method, Scaling effects

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