Convective heat transfer in pressure-driven nitrogen slip flows in long microchannels: The effects of pressure work and viscous dissipation

2012 ◽  
Vol 55 (13-14) ◽  
pp. 3488-3497 ◽  
Author(s):  
Zhanyu Sun ◽  
Yogesh Jaluria
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Viscous Dissipation ◽  
Convective Heat ◽  
Pressure Work ◽  
Slip Flows ◽  
Pressure Driven

Pressure Work and Viscous Dissipation Effects on Heat Transfer in a Parallel–Plate Microchannel Gas Flow

2017 ◽  
Vol 35 (02) ◽  
pp. 243-254 ◽  
Author(s):  
K. M. Ramadan
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Viscous Dissipation ◽  
Convective Heat ◽  
Parallel Plate ◽  
Gas Flow ◽  
Combined Effect ◽  
Rarefaction Analysis ◽  
Pressure Work ◽  
Axial Conduction

ABSTRACTConvective heat transfer in a parallel plate microchannel gas flow is investigated analytically and numerically, considering the effects of viscous dissipation, pressure work, shear work, axial conduction and rarefaction. Analysis is performed with constant wall temperature and constant wall heat flux boundary conditions for both gas cooling and heating. The results presented demonstrate the significance of the combined effect of pressure work and viscous dissipation, shear work, rarefaction degree and axial conduction on microchannel convective heat transfer, in both the thermally developing and fully developed flow regions. Viscous dissipation and pressure work in a pressure-driven microchannel gas flow are of comparable magnitudes and may not be neglected from the energy equation. The shear work at the wall, which is effectively the combined effect of viscous dissipation and pressure work, needs to be included in the Nusselt number for better predictions of heat transfer.

Effects of Creep Flow and Viscous Dissipation in the Slip Regime for Isoflux Rectangular Microchannels

2007 ◽  
Author(s):  
Jennifer van Rij ◽  
Tim Ameel ◽  
Todd Harman
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Pressure Drop ◽  
Convective Heat Transfer ◽  
Viscous Dissipation ◽  
Convective Heat ◽  
Numerical Algorithm ◽  
Slip Flow ◽  
Creep Flow ◽  
Nusselt Numbers

The effects of rarefaction on convective heat transfer and pressure drop characteristics are numerically evaluated for uniform wall heat flux rectangular microchannels. Results are obtained by numerically solving the momentum and energy equations with both first- and second-order slip velocity and temperature jump boundary conditions. The resulting velocity and temperature fields are then evaluated to obtain the microchannel Poiseuille and Nusselt numbers. In addition to the effects of rarefaction, the effects of aspect ratio, thermal creep flow, and viscous dissipation are investigated for locally fully developed Poiseuille and Nusselt numbers. The constant wall heat flux results obtained in this study are compared to constant wall temperature results obtained previously, using the same numerical algorithm, at various aspect ratios including the limiting case of parallel plate microchannels. In addition to supplying previously unreported data on slip flow convective heat transfer and pressure drop characteristics, these results verify the numerical algorithm for more complex future slip flow analyses.

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