scholarly journals Jeffery-Hamel slip flow in a convergent microchannel with uniform wall temperature and streamwise heat conduction

2019 ◽  
Vol 286 ◽  
pp. 08010
Author(s):  
Mohammed Niagui ◽  
Youssef Haddout ◽  
Abdelaziz Oubarra ◽  
Jawad Lahjomri
Keyword(s):  
Heat Conduction ◽  
Analytical Solution ◽  
Slip Flow ◽  
Thermal Characteristics ◽  
Three Dimensions ◽  
Uniform Wall Temperature ◽  
Uniform Wall ◽  
Flow Through ◽  
Laminar Forced Convection

This work is devoted to the determination of the analytical solution of the problem of the laminar forced convection of the Jeffery-Hamel slip flow through a convergent microchannel. The analytical solution is obtained by using a self-adjoint formalism of the functional analysis. The solution represents an extension of the solution obtained in the conventional continuum flow by considering the boundaries slip conditions at the wall and the streamwise heat conduction. This extension has been done by using a new matrix operator of three dimensions in the Hilbert space. The results show that the thermal characteristics are strongly influenced by the Reynolds, Prandtl and Knudsen numbers, the aperture angle of the channel and the streamwise heat conduction.

Second Order Slip Flow Effects on Heat Transfer Performance of Microchannels

2009 ◽  
Author(s):  
Cem Dolu ◽  
Lu¨tfullah Kuddusi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Flow Model ◽  
Slip Flow ◽  
Second Order ◽  
Flow Models ◽  
Uniform Wall Temperature ◽  
Uniform Wall ◽  
Slip Flow Regime ◽  
Flow Effects

First and second order slip flow models in rectangular microchannels heated at constant and uniform wall temperature are studied. The velocity and temperature profiles for hydrodynamically and thermally developed incompressible slip flow regime available in literature are used. The average nondimensional slip velocity and temperature jump are found by using first and second order slip flow models. The average Nusselt number is also derived by using both first and second order slip flow models. The effects of Knudsen number, aspect ratio and second order slip flow model on the heat transfer characteristics of microchannel are explored.

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.

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.

Optimal Removal of Experimental Points to Determine Apparent Thermal Diffusivity of Canned Products

2014 ◽  
Vol 10 (2) ◽  
pp. 223-231 ◽  
Author(s):  
Wilton P. da Silva ◽  
Cleide M. D. P. S. Silva ◽  
Marcos A. A. Lins ◽  
Waldemir S. da Costa
Keyword(s):  
Boundary Condition ◽  
Heat Conduction ◽  
Thermal Diffusivity ◽  
Analytical Solution ◽  
Heat Conduction Equation ◽  
Transient Heat Conduction ◽  
Agar Gel ◽  
Precision And Accuracy ◽  
Thermo Physical Properties

Abstract To describe the transient heat conduction from or to a product, its thermo-physical properties must be known. If the boundary condition of the heat conduction equation is of the first kind, the process is governed by the thermal diffusivity α. Normally this property is determined by fit of the analytical solution with only the first term of the series to an experimental dataset of the temperature versus time, in which the temperature is measured in a known position. In this case, the value obtained for α contains errors due to the consideration of only one term and the inclusion of the first experimental points in the fit. This article presents an algorithm based on optimal removal of experimental points to minimize errors in the determination of α. The algorithm was validated and applied to heating of Agar gel. The precision and accuracy of the obtained result were, respectively, 0.38 and 0.6%.

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