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Laminar forced convection in annular microchannels with slip flow regime

Sadeghi, A ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1115/ICNMM2009-82013
  3. Abstract:
  4. Fluid flow and heat transfer at microscale have attracted an important research interest in recent years due to the rapid development of microelectromechanical systems (MEMS). Fluid flow in microdevices has some characteristics which one of them is rarefaction effect related with gas flow. In this research, hydrodynamically and thermally fully developed laminar rarefied gas flow in annular microducts is studied using slip flow boundary conditions. Two different cases of the thermal boundary conditions are considered, namely: uniform temperature at the outer wall and adiabatic inner wall (Case A) and uniform temperature at the inner wall and adiabatic outer wall (Case B). Using the previously obtained velocity distribution, energy conservation equation subjected to relevant boundary conditions is numerically solved using fourth order Runge-Kutta method. The Nusselt number values are presented in graphical form as well as tabular form. It is realized that for the case A increasing aspect ratio results in increasing the Nusselt number, while the opposite is true for the case B. The effect of aspect ratio on Nusselt number is more notable at smaller values of Knudsen number, while its effect becomes slighter at large Knudsen numbers. Also increasing Knudsen number leads to smaller values of Nusselt number for the both cases
  5. Keywords:
  6. Fourth order ; Gas flows ; Graphical forms ; Inner walls ; Knudsen number ; Laminar forced convections ; Micro devices ; Micro-scales ; Microannulus ; Microducts ; Microelectromechanical systems ; Rapid development ; Rarefied gas flow ; Slip flow ; Slip flow regimes ; Slip-flow boundary conditions ; Uniform temperature ; Aerodynamics ; Boundary conditions ; Electromechanical devices ; Flow of gases ; Laminar flow ; MEMS ; Microchannels ; Nusselt number ; Pressure drop ; Runge Kutta methods ; Aspect ratio
  7. Source: 7th International Conference on Nanochannels, Microchannels, and Minichannels, 22 June 2009 through 24 June 2009 ; Issue PART A , 2009 , Pages 353-361 ; 9780791843499 (ISBN)
  8. URL: http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1626564