DSMC Study of Pressure-Driven Slip Flow through Microchannel at Non-Uniform Wall Temperature

2015 ◽  
Vol 31 (3) ◽  
pp. 279-289
Author(s):  
C.-C. Tai ◽  
P.-Y. Tzeng ◽  
C.-Y. Soong
Keyword(s):  
Temperature Gradient ◽  
Wall Temperature ◽  
Gas Flow ◽  
Slip Flow ◽  
Thermal Creep ◽  
Adiabatic Wall ◽  
Uniform Wall Temperature ◽  
Creep Effect ◽  
Uniform Wall ◽  
Pressure Driven

ABSTRACTThe present study is to investigate the pressure-driven gas flow in microchannel at no-uniform wall temperature. DSMC is employed to generate the flow field details which are then used in analysis of the slip flow characteristics. The major concern is the influences of thermal creep effect on the pressure-driven slip flow. Thermal creep is resulted from tangential wall temperature gradient. In this work, two kinds of thermal boundary condition are considered. One is the linearly varied temperature (LVT) applied to both walls, the other is that has the bottom wall at a thermal condition combined LVT and adiabatic (AD) wall, i.e. LVT-AD-LVT condition. The present DSMC results reveal that the fluid slip is weakened (enhanced) in the case with a negative (positive) wall temperature gradient. Relatively, thermal creep effect on fluid slip over the adiabatic wall is more pronounced in the presence of negative wall temperature gradient. The mass flowrate is a strong function of the wall temperature gradient. However, there is only little difference between the mass flowrates predicted under the two kinds of thermal conditions studied in the present work.

Laminar Heat Transfer in Tubes Under Slip-Flow Conditions

1962 ◽  
Vol 84 (4) ◽  
pp. 363-369 ◽  
Author(s):  
E. M. Sparrow ◽  
S. H. Lin
Keyword(s):  
Heat Transfer ◽  
Wall Temperature ◽  
Slip Flow ◽  
Mean Free Path ◽  
Uniform Wall Temperature ◽  
Nusselt Numbers ◽  
Temperature Jumps ◽  
Uniform Wall ◽  
Moving Fluid ◽  
Uniform Wall Heat Flux

The effects of low-density phenomena on the fully developed heat-transfer characteristics for laminar flow in tubes has been studied analytically. Consideration is given to the slip-flow regime wherein the major rarefaction effects are manifested as velocity and temperature jumps at the tube wall. The analysis is carried out for both uniform wall temperature and uniform wall heat flux. In both cases, the slip-flow Nusselt numbers are lower than those for continuum flow and decrease with increasing mean free path. Extension of the results is made to include the effects of shear work at the wall, temperature jump modifications for a moving fluid, and thermal creep.

Thermal Transport Phenomena in Turbulent Gas Flow Through a Tube at High Temperature Difference and Uniform Wall Temperature

1998 ◽  
Vol 120 (3) ◽  
pp. 784-787 ◽  
Author(s):  
Shuichi Torii ◽  
Wen-Jei Yang
Keyword(s):  
Heat Flux ◽  
High Temperature ◽  
Temperature Difference ◽  
Wall Temperature ◽  
Thermal Transport ◽  
Gas Flow ◽  
Uniform Wall Temperature ◽  
Uniform Wall ◽  
Flow Through ◽  
Turbulent Gas Flow

A numerical study is performed to investigate thermal transport phenomena in turbulent gas flow through a tube heated at high temperature difference and uniform wall temperature. A k-ε turbulence model is employed to determine the turbulent viscosity and the turbulent kinetic energy. The turbulent heat flux is expressed by a Boussinesq approximation in which the eddy diffusivity of the heat is determined by a t2-ε, heat transfer model. The governing boundary layer equations are discretized by means of a control-volume finite difference technique and are numerically solved using a marching procedure. It is disclosed from the study that (i) laminarization takes place in a turbulent gas flow through a pipe with high uniform wall temperature just as it does in a pipe with high unform wall heat flux, and (ii) the flow in a tube heated to high temperature difference and uniform wall temperature is laminarized at a lower heat than that under the uniform heat flux condirion.

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