Investigation of flow and heat transfer characteristics of rarefied gaseous slip flow in nonplanar micro-Couette configuration

The effects of variable physical properties on the flow and heat transfer characteristics of simultaneously developing slip-flow in rectangular microchannels with constant wall heat flux are numerically investigated. A co-located finite-volume method is used in order to solve the mass, momentum and energy equations in their most general form. Thermophysical properties of the flowing gas are functions of temperature, while density and Knudsen number are allowed to change with both pressure and temperature. Different Knudsen numbers are considered in order to study the effects of slip-flow. Simulations indicate that the constant physical property assumption can result in under/over-prediction of the local friction and heat transfer coefficients depending on the problem configuration. Density and thermophysical property variations have significant effects on predicting flow and heat transfer characteristics since the gas temperature constantly changes as a result of the applied wall heat flux. Heat transfer coefficient is affected both due to the change in the velocity field and change in thermophysical properties. Also temperature dependence of the local Knudsen number can significantly alter the friction coefficients due to its strong dependence on slip conditions. The degree of discrepancy varies for different cases depending on the Knudsen number, and the applied heat flux strength and direction (cooling versus heating).

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Investigation of Fluid Flow and Heat Transfer Characteristics of Gases in Microchannels with Consideration of Different Roughness Shapes at Slip Flow Regime

Nanoscale and Microscale Thermophysical Engineering ◽

10.1080/15567265.2010.500317 ◽

2010 ◽

Vol 14 (3) ◽

pp. 137-151 ◽

Cited By ~ 8

Author(s):

S. Hossainpour ◽

M. Hakak Khadem

Keyword(s):

Heat Transfer ◽

Fluid Flow ◽

Flow Regime ◽

Slip Flow ◽

Heat Transfer Characteristics ◽

Transfer Characteristics ◽

Flow And Heat Transfer ◽

Slip Flow Regime

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Convective Hydromagentic Slip Flow with Variable Properties Due to a Porous Rotating Disk

Sultan Qaboos University Journal for Science [SQUJS] ◽

10.24200/squjs.vol15iss0pp55-79 ◽

2010 ◽

Vol 15 ◽

pp. 55 ◽

Cited By ~ 6

Author(s):

Mohammad M. Rahman

Keyword(s):

Heat Transfer ◽

Boundary Layer ◽

Slip Flow ◽

Rotating Disk ◽

Heat Transfer Characteristics ◽

Temperature Dependent ◽

Transfer Characteristics ◽

Similarity Transformations ◽

Flow And Heat Transfer ◽

Highly Nonlinear

In this paper we investigate convective heat transfer characteristics of steady hydromagnetic slip flow over a porous rotating disk taken into account the temperature dependent density, viscosity and thermal conductivity in the presence of Hall current, viscous dissipation and Joule heating. Using von-Karman similarity transformations we reduce the governing equations for flow and heat transfer into a system of ordinary differential equations which are highly nonlinear and coupled. The resulting nondimensional equations are solved numerically by applying Nachtsheim-Swigert iteration technique. The results show that when modeling a thermal boundary layer, with temperature dependent fluid properties, consideration of Prandtl number as constant within the boundary layer, produces unrealistic results. therefore Therefore it must be treated as variable throughout the boundary layer. Results also show that the slip factor significantly controls the flow and heat transfer characteristics.

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