Theoretical and experimental investigation on heating moving packed beds in a single tube with constant wall temperature

Fluid flow and heat transfer in the entrance region of rectangular microchannels of various aspect ratios are numerically investigated in the slip-flow regime with particular attention to thermal creep effects. Uniform inlet velocity and temperature profiles are prescribed in microchannels with constant wall temperature. An adiabatic section is also employed at the inlet of the channel in order to prevent unrealistically large axial temperature gradients due to the prescribed uniform inlet temperature as well as upstream diffusion associated with low Reynolds number flows. A control-volume technique is used to solve the Navier–Stokes and energy equations which are accompanied with appropriate velocity slip and temperature jump boundary conditions at the walls. Despite the constant wall temperature, axial and peripheral temperature gradients form in the gas layer adjacent to the wall due to temperature jump. The simultaneous effects of velocity slip, temperature jump and thermal creep on the flow and thermal patterns along with the key flow parameters are examined in detail for a wide range of cross-sectional aspect ratios, and Knudsen and Reynolds numbers. Present results indicate that thermal creep effects influence the flow field and the temperature distribution significantly in the early section of the channel.

Download Full-text

Further note on an approximate method for calculating heat transfer in laminar boundary-layers with constant wall temperature

International Journal of Heat and Mass Transfer ◽

10.1016/0017-9310(62)90093-5 ◽

1962 ◽

Vol 5 (7) ◽

pp. 697-700 ◽

Cited By ~ 1

Author(s):

A.G. Smith ◽

V.L. Shah

Keyword(s):

Heat Transfer ◽

Approximate Method ◽

Boundary Layers ◽

Wall Temperature ◽

Constant Wall Temperature ◽

Laminar Boundary Layers

Download Full-text

Exact Solutions for Unsteady Free Convection Flow of Casson Fluid over an Oscillating Vertical Plate with Constant Wall Temperature

Abstract and Applied Analysis ◽

10.1155/2015/946350 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 9

Author(s):

Asma Khalid ◽

Ilyas Khan ◽

Sharidan Shafie

Keyword(s):

Differential Equations ◽

Exact Solutions ◽

Wall Temperature ◽

Vertical Plate ◽

Fluid Model ◽

Casson Fluid ◽

Convection Flow ◽

Constant Wall Temperature ◽

Transform Method ◽

Casson Fluid Model

The unsteady free flow of a Casson fluid past an oscillating vertical plate with constant wall temperature has been studied. The Casson fluid model is used to distinguish the non-Newtonian fluid behaviour. The governing partial differential equations corresponding to the momentum and energy equations are transformed into linear ordinary differential equations by using nondimensional variables. Laplace transform method is used to find the exact solutions of these equations. Expressions for shear stress in terms of skin friction and the rate of heat transfer in terms of Nusselt number are also obtained. Numerical results of velocity and temperature profiles with various values of embedded flow parameters are shown graphically and their effects are discussed in detail.

Download Full-text