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Abstract: The
heat transfer characteristics of gas slip flowing in the rectangular
microchannels heated unsymmetrically with constant axial heat flux are
analyzed theoretically for the slip flow regime. The energy equation
with temperature jump boundary conditions in slip flow regime is solved
by a computation-oriented method of the orthonormal function analysis.
The dimensionless temperature profiles and the average Nusselt numbers
for various thermal boundary conditions are obtained and com-pared with
those in macrochannel under the same conditions. The effects of Knudsen
number, aspect ratio, and thermal boundary conditions on the heat
transfer characteristics in slip flow regime are discussed,
respectively. The calculated results show that the average Nusselt
numbers in rectangular microchannels is lower for slip flow than for
no-slip flow under any heating condition, and decreases with increasing
Knudsen number. The smaller the aspect ratio is, the more the decrease
of the average Nusselt number is. The decrease of the average Nusselt
number in rectangular microchannel compared with the macrochannel for
the condition of only one wall heated is the smallest at the same
Knudsen number and aspect ratio compared with others heating conditions.
Key
words: Slip
flow regime Rectangular microchannel Unsymmetrical thermal
boundary Heat transfer characteristics
CLC No: TK124
国家自然科学基金(90410005)、教育部优秀青年教师资助计划(教人司[2003]355号文)、重庆市应用基础研究(2003-7966)和重庆大学骨干教
师资助项目. Received 20040706, received in revised form 20041217
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