scholarly journals Experimental and Numerical Study on Heat Transfer in Nonhomogeneous Seepage Flow Field

1986 ◽  
Vol 30 ◽  
pp. 271-276
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Numerical Study ◽  
Seepage Flow ◽  
Seepage Flow Field

Magnetohydrodynamic effects on flow structures and heat transfer over two cylinders wrapped with a porous layer in side

2016 ◽  
Vol 26 (5) ◽  
pp. 1416-1432 ◽  
Author(s):  
Saman Rashidi ◽  
Javad Abolfazli Esfahani ◽  
Mohammad Sadegh Valipour ◽  
Masoud Bovand ◽  
Ioan Pop
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Flow Field ◽  
Porous Layer ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Circular Cylinders ◽  
Flow Structures ◽  
Content Type ◽  
The Magnetic Field

Purpose – The analysis of the flow field and heat transfer around a tube row or tube banks wrapped with porous layer have many related engineering applications. Examples include the reactor safety analysis, combustion, compact heat exchangers, solar power collectors, high-performance insulation for buildings and many another applications. The purpose of this paper is to perform a numerical study on flows passing through two circular cylinders in side-by-side arrangement wrapped with a porous layer under the influence of a magnetic field. The authors focus the attention to the effects of magnetic field, Darcy number and pitch ratio on the mechanism of convection heat transfer and flow structures. Design/methodology/approach – The Darcy-Brinkman-Forchheimer model for simulating the flow in porous medium along with the Maxwell equations for providing the coupling between the flow field and the magnetic field have been used. Equations with the relevant boundary conditions are numerically solved using a finite volume approach. In this study, Stuart and Darcy numbers are varied within the range of 0 < N < 3 and 1e-6 < Da < 1e-2, respectively, and Reynolds and Prandtl numbers are equal to Re=100 and Pr=0.71, respectively. Findings – The results show that the drag coefficient decreases for N < 0.6 and increases for N > 0.6. Also, the effect of magnetic field is negligible in the gap between two cylinders because the magnetic field for two cylinders counteracts each other in these regions. Originality/value – To the authors knowledge, in the open literature, flow passing over two circular cylinders in side-by-side arrangement wrapped with a porous layer has been rarely investigated especially under the influence of a magnetic field.

Effects of a flow mode transition on natural convection heat transfer in a heat tracing enclosure

2018 ◽  
Vol 233 (3) ◽  
pp. 489-499 ◽  
Author(s):  
CJ Ho ◽  
GN Sou ◽  
CM Lai
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Flow Field ◽  
Numerical Study ◽  
Flow Direction ◽  
Convection Heat Transfer ◽  
Flow Mode ◽  
Mode Transition ◽  
Flow And Heat Transfer ◽  
Lower Variation

This paper presents a numerical study of transient buoyancy-induced fluid flow and heat transfer between two horizontal, differentially heated pipelines inside a circular, air-filled enclosure. Numerical simulations based on the finite difference method were conducted to investigate the flow mode transition of the buoyant airflow and its effects on the heat transfer characteristics of the pipelines. The results indicate that the fluid flow complexity and the heat transfer of air between the pipelines are strongly affected by the Rayleigh number. When Ra = 6 × 105 and 1.2 × 106, both the flow field and the temperature distribution exhibit periodic variations with different patterns. The former ( Ra = 6 × 105) is a complete alteration of the flow direction from clockwise to counterclockwise, whereas the latter is a variation in the flow field strength that varies between strong and weak. The latter has a lower variation frequency than that of the former.

The Effects of Fluid Boundary Types on Flow around and Heat Transfer from an Elliptical Cylinder

2014 ◽  
Vol 1065-1069 ◽  
pp. 2117-2122
Author(s):  
Hong Yan Zhai ◽  
Qing Ling Li ◽  
Liang Huang
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Numerical Study ◽  
Elliptical Cylinder ◽  
Cylinder Surface ◽  
Recirculation Bubble ◽  
Nusselt Numbers ◽  
Fluid Boundary

A numerical study was conducted to examine the flow field around and heat transfer from an elliptical cylinder of AR=0.5 in two types of the annular boundary and rectangular one. The fluid near the surface separates from the cylinder surface and forms a steady recirculation bubble at the rear end of the cylinder at the first critical Reynolds (Rec1). The vortices begins the alternating separation at the second critical Reynolds (Rec2). Rec1 and Rec2 for the fluid in two boundary types are studied. The Nusselt numbers are compared at Rec1 and Rec2 respectively.

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