illustrates an exploded view of the test section. The 21
parallel rectangular micro-channels of 0.45 0.41 mm
(width depth) with a 0.54 mm wall thickness between each
channel were fabricated on the copper block in which a cartridge
heater with adjustable input power was installed. The length of
the micro-channels was 40 mm. On the top of the test section,
the cover plate made of polycarbonate was placed to allow optical
access for flow visualization. The copper block was well insulated
by G10 epoxy. Metal plates and the insulators were bolted together
with the copper block and the cover plate to firm up the assembly.
The cover plate, which is transparent, served as a viewing window
for flow visualization. The detailed formation of flow pattern
was registered by precise Stereozoom microscope mounted together
with a camera having shutter speeds of 1/15–1/10,000 s.
An adjustable LED light source was placed perpendicular to the
viewing section.