Micro Effects for Single Phase Pressure Drop In Microchannels.
Micro Effects for Single Phase Pressure Drop In
Microchannels.
(1536 K)
Han, D. H.; Kedzierski, M. A.
International Journal of Transport Phenomena, Vol. 10,
103-112, 2008.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Korea Science and Engineering Foundation, Korea
Keywords:
micro effects; pressure drop; microchannels;
temperature; pressure; uncertainity; Reynolds number;
friction; equations; regression
Abstract:
This paper investigates the significance of several
micro-effects that have been proposed to influence
pressure drop measurements in microchannels. Pressure
drop measurements were made for liquid flow within
tubular microchannels nominally ranging in diameters
from 97 mm to 260 mm and Reynolds numbers from 30 to
3000. Fused silica tubes, polyetheretherketone tubes,
and stainless steel tubes were examined. Distilled
water, tap water, and deionized water were used to
investigate the effect of the fluid's ionic
composition on the pressure drop. The combination of
differing tube surfaces and differing ionic composition
was use to examine the influence of surface polarity.
The effect of micro particles was investigated by
testing filtered and unfiltered test fluids. Statistical
examination of the measurements showed that most all of
the friction factor measurements exhibited the same
dependence on Reynolds number despite variation in tube
length, tube material, tube diameter, fluid type, and
filtering. In addition, the measurements agreed well
with classical theory. This includes the fact that no
early transition from laminar flow to turbulent flow was
observed. Finally, it was shown that the present
pressure drop measurements were not significantly
affected by viscous dissipation.
