| Summary: | 碩士 === 國立清華大學 === 動力機械學系 === 82 === A study of non-Darcian forced convection in an asymmetric
heating sintered porous channel was carry out to investigate
the feasibility of using this channel as a heat sink for high
performance forced water cooling in microelectronics. This
paper presents the results of heat transfer measurement for two
5×5×1 cm porous channels with sintered bronze beads of d=0.72
and 1.59 mm. The local wall temperature distribution, inlet and
outlet pressures and temperatures , and heat transfer
coefficients were measured for heat fluxes between 2 and 9 W/c
㎡, and with water velocity ranging from 0 to 11.7 cm/s. The
measurement covers the data in both the thermal entrance and
thermal fully developed regions. The main objective of the
present study is to examine the effects of the particle
Reynolds number, the Peclet number, and the ratio of channel
height to particle diameter on the local Nusselt number. In the
thermal developing region, the results show that the local heat
transfer coefficients increase with the decrease in the
particle size and the increase in the fluid velocity, but
decrease with the increase in the axial distance before
reaching its fully developed value. The high conductivity
porous channel enchances the heat transfer and the maximum wall
temperature could be reduced drastically. For example, the
forced water cooling can be extended upto 0.25—4 W/c㎡℃ by a
porous heat sink and maintaining a maximum wall temperature
less than 45℃. But for forced air cooling, the heat transfer
coefficents are about from 0.01 to 0.5 W/c㎡℃。
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