Heat Transfer in Microchannels.
LOUISIANA TECH UNIV RUSTON
Pagination or Media Count:
The objective of this research was to develop an analytical solution to the heat transfer problem in microchannels with slip-flow and an isothermal wall, a heat transfer problem for gases at low pressures or in extremely small geometries, and to verify this solution experimentally. In this investigation, an analytical expression for the velocity distribution with slip-flow was obtained which involved the Knudsen number Kn in an infinite series form. Kn for extremely small channels may become large enough to significantly affect the velocity distribution and consequently affect the heat transfer properties. A mathematical model of temperature distribution was established by combining the energy and momentum equations. A new technique for evaluation of eigenvalues for the solution of the heat transfer problem in microchannels was developed from the method of Frobenius. The computational results show that the method is effective. The local and average Nusselt numbers were found for 0.005Kn0.30 with aspect ratio a1, 23, 12, 14, and 18. Experiments for helium flow in a rectangular microchannel of dimension 117 microns x 24 microns x 63.5 microns and a microtube with inside diameter of 52 microns were conducted.
- Fluid Mechanics