Heat transfer enhancement in a vertical channel with asymmetric isothermal walls by local blowing or suction

Jeng, Yih; Chen, Jiann Lin; Chen, Yeong-Ysong; Aung, Win

doi:10.1016/0142-727x(94)00004-v

Cited by 6 publications

(2 citation statements)

References 15 publications

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“…Developing as well as fully developed convection in vertical parallel plates, tube, annulus, and double‐passage channels is a subject of interest for many researchers. Jeng et al 1 investigated mixed convection heat transfer numerically by fixing porous wall segments on the hot wall in a vertical parallel channel. Improvement in heat transfer is due to increase in porosity, position of porous wall segment for lower values of Re.…”

Section: Introductionmentioning

confidence: 99%

Developing buoyant convection in vertical porous annuli with unheated entry and exit

2020

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The open‐ended vertical double‐passage annular space between three vertical concentric coaxial cylinders is an important physical configuration portraying many practical applications. Hence, in the present analysis, the developing buoyant convection in vertical double‐passage annuli filled with fluid‐saturated porous media is studied numerically by imposing unheated entry and unheated exit thermal boundary conditions. The numerical solutions of the mathematical model equations are found through finite difference technique. The velocity profiles in radial as well as axial directions and temperature profiles have been depicted for vast range of nondimensional numbers, baffle position, and heating and un‐heating ratio. The velocity and thermal gradients decreases as heating section length decreases. Maximum velocity and heat transport occurs in a narrow annular passage rather than equal or wider passages. The presence of porosity causes a reduction in flow velocities and thermal gradients.

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Section: Introductionmentioning

confidence: 99%

Developing buoyant convection in vertical porous annuli with unheated entry and exit

2020

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“…Chen [16] studied forced heat transfer over a flat plate subjected to suction and blowing and continuously moving in a quiescent or flowing fluid. Jeng et al [17] studied the possibility of enhancing heat transfer between two vertical parallel plates with suction and blowing through a porous segment on one of the walls. Marom et al [18] studied the effect of suction and pulsed blowing on the laminar boundary layer of the flow over a plate, experimentally.…”

Section: Introductionmentioning

confidence: 99%

Combined effect of roughness and suction/blowing in a laminar micro-channel flow

Khezerloo¹,

Djenidi²

2020

Australasian Fluid Mechanics Conference (AFMC)

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The combined effect of roughness and suction/blowing in laminar micro-channel flow was investigated numerically to determine whether turbulence can be generated and maintained at low Reynolds numbers. The square bar elements are mounted on the channels' bottom wall; slits are cut on the bars to suck and blow. Two cases are considered: one when the bars span the entire width of the channel, the second when they span along half of the width. The numerical study was performed using the Finite Volume Method (FVM). Different configurations of suction and blowing at different rates are considered. The results showed that the second case leads to generate secondary motions that disturb the laminar flow pattern.

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Simultaneous Optimization of Shape and Flow Parameters for Combined Free and Forced Convection in Vertical Channels

Meriç

1997

Int. J. Numer. Meth. Engng.

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Simultaneous optimization of shape and flow parameters is performed for a combined free and forced convection flow through vertical rectangular channels with moving walls. The laminar flow is assumed to be fully developed in the axial direction. The wall velocity, the axial pressure gradient and the channel height in the transverse plane are taken as the optimization parameters. The sensitivity expressions of both the objective function and the flow rate constraint of optimization are obtained in terms of the relevant physical variables, as well as adjoint variables which satisfy additional p.d.e.'s. All equations are discretized using the finite element method. Numerical results are provided for the present constrained optimization problem for various values of the problem parameters which include the moving wall segment size and the Rayleigh number. The results indicate that with increased Rayleigh number the optimal values of the wall velocity and the axial pressure gradient are increased, while the optimal value of the channel height is decreased. General sensitivity expressions are also presented in the appendix which might be utilized for arbitrary boundary variations along with arbitrary optimization objectives in other investigations.

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Heat transfer enhancement in a vertical channel with asymmetric isothermal walls by local blowing or suction

Cited by 6 publications

References 15 publications

Developing buoyant convection in vertical porous annuli with unheated entry and exit

Developing buoyant convection in vertical porous annuli with unheated entry and exit

Combined effect of roughness and suction/blowing in a laminar micro-channel flow

Simultaneous Optimization of Shape and Flow Parameters for Combined Free and Forced Convection in Vertical Channels

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