Heat Transfer in a Shallow Cavity

2016 ◽  
pp. 179-183
Author(s):  
Fatima Madi Arous
Keyword(s):  
Heat Transfer ◽  
Shallow Cavity

NUMERICAL INVESTIGATION OF CONJUGATE HEAT TRANSFER FROM LAMINAR WALL JET FLOW OVER A SHALLOW CAVITY

2018 ◽  
Vol 49 (12) ◽  
pp. 1151-1170 ◽  
Author(s):  
Maheandera Prabu Paulraj ◽  
Rajesh Kanna Parthasarathy ◽  
Jan Taler ◽  
Dawid Taler ◽  
Pawel Oclon ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Investigation ◽  
Conjugate Heat Transfer ◽  
Jet Flow ◽  
Wall Jet ◽  
Shallow Cavity ◽  
Wall Jet Flow

scholarly journals Laminar Wall Jet Flow and Heat Transfer over a Shallow Cavity

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
P. Maheandera Prabu ◽  
K. P. Padmanaban
Keyword(s):  
Heat Transfer ◽  
Stokes Equations ◽  
Vortex Formation ◽  
Leading Edge ◽  
Step Length ◽  
Jet Flow ◽  
Maximum Temperature ◽  
Wall Jet ◽  
Shallow Cavity ◽  
Wall Jet Flow

This paper presents the detailed simulation of two-dimensional incompressible laminar wall jet flow over a shallow cavity. The flow characteristics of wall jet with respect to aspect ratio (AR), step length (Xu), and Reynolds number (Re) of the shallow cavity are expressed. For higher accuracy, third-order discretization is applied for momentum equation which is solved using QUICK scheme with SIMPLE algorithm for pressure-velocity coupling. Low Reynolds numbers 25, 50, 100, 200, 400, and 600 are assigned for simulation. Results are presented for streamline contour, velocity contour, and vorticity formation at wall and also velocity profiles are reported. The detailed study of vortex formation on shallow cavity region is presented for various AR,Xu, and Re conditions which led to key findings as Re increases and vortex formation moves from leading edge to trailing edge of the wall. Distance between vortices increases when the step length (Xu) increases. When Re increases, the maximum temperature contour distributions take place in shallow cavity region and highest convection heat transfer is obtained in heated walls. The finite volume code (FLUENT) is used for solving Navier-Stokes equations and GAMBIT for modeling and meshing.

scholarly journals Numerical Investigation of Flow and Heat Transfer over a Shallow Cavity: Effect of Cavity Height Ratio

Fluids ◽  
2021 ◽  
Vol 6 (7) ◽  
pp. 244
Author(s):  
Salem S. Abdel Aziz ◽  
Abdel-Halim Saber Salem Said
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Average Nusselt Number ◽  
Flow Behavior ◽  
Cavity Flow ◽  
Bottom Wall ◽  
Recirculation Region ◽  
Height Ratio ◽  
Shallow Cavities ◽  
Shallow Cavity

Flow over shallow cavities is used to model the flow field and heat transfer in a solar collector and a variety of engineering applications. Many studies have been conducted to demonstrate the effect of cavity aspect ratio (AR), but very few studies have been carried out to investigate the effect of cavity height ratio (HR) on shallow cavity flow behavior. In this paper, flow field structure and heat transfer within the 3-D shallow cavity are obtained numerically for two height ratio categories: HR = 0.0, 0.25, 0.5, 0.75, and 1.0 and HR = 1.25, 1.5, 1.75, 2.0, 2.25, and 2.5. The governing equations, continuity, momentum, and energy are solved numerically and using the standard (K-ε) turbulence model. ANSYS FLUENT 14 CFD code is used to perform the numerical simulation based on the finite volume method. In this study, the cavity aspect ratio, AR = 5.0, and Reynolds number, Re = 3 × 105, parameters are fixed. The cavity’s bottom wall is heated with a constant and uniform heat flux (q = 740 W/m2), while the other walls are assumed to be adiabatic. For the current Reynolds number and cavity geometry, a single vortex structure (recirculation region) is formed and occupies most of the cavity volume. The shape and location of the vortex differ according to the height ratio. A reverse velocity profile across the recirculation region near the cavity’s bottom wall is shown at all cavity height ratios. Streamlines and temperature contours on the plane of symmetry and cavity bottom wall are displayed. Local static pressure coefficient and Nusselt number profiles are obtained along the cavity’s bottom wall, and the average Nusselt number for various height ratios is established. The cavity height ratio (HR) is an important geometry parameter in shallow cavities, and it plays a significant role in the cavity flow behavior and heat transfer characteristics. The results indicate interesting flow dynamics based on height ratio (HR), which includes a minimal value in average Nusselt number for HR ≈ 1.75 and spatial transitions in local Nusselt number distribution along the bottom wall for different HRs.

scholarly journals Heat transfer prediction in a shallow cavity effect of incoming flow characteristics

2016 ◽  
Vol 20 (5) ◽  
pp. 1519-1532
Author(s):  
Arous Madi
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Flow Characteristics ◽  
Wall Jet ◽  
Incoming Flow ◽  
Cavity Depth ◽  
Nozzle Height ◽  
Shallow Cavity ◽  
Wall Jet Flow ◽  
Flow Case

This study deals numerically with a heat transfer in a turbulent flow over a shallow cavity. Two different configurations of the incoming flow are considered: a boundary layer flow and a plane wall jet flow, in order to examine the wall jet outer layer effect on the heat transfer. This layer is an important additional turbulence source in the wall jet flow. Reynolds number and turbulence intensity effects were investigated in the boundary layer incoming flow case. The cavity depth to nozzle height ratio effect was examined in the wall jet incoming flow case. The numerical approach is based on k-? standard turbulence model. This study reveals that the heat transfer is very sensitive to the incoming flow characteristics. The turbulence intensity increase accelerates the reattachment of the shear layer at the cavity floor and enhances the heat transfer. The reattachment phenomenon seems to be less affected by the Reynolds number. However, an increase in this parameter ameliorates the heat transfer. It was also observed a heat transfer enhancement in the wall jet incoming flow case as compared to that of a boundary layer. Likewise, it was found that the augmentation of the cavity depth to the jet nozzle height ratio improves even more the heat transfer. The maximum heat transfer occurs upstream of the reattachment.

Heat Transfer Studies in the Flow Over Shallow Cavities

2004 ◽  
Vol 127 (7) ◽  
pp. 699-712 ◽  
Author(s):  
Paulo S. B. Zdanski ◽  
M. A. Ortega ◽  
Nide G. C. R. Fico
Keyword(s):  
Heat Transfer ◽  
Stokes Equations ◽  
Numerical Study ◽  
Fluid Flows ◽  
Computer Code ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Shallow Cavities ◽  
Shallow Cavity ◽  
Desirable Effect

Fluid flows along a shallow cavity. A numerical study was conducted to investigate the effects of heating the floor of the cavity. In order to draw a broader perspective, a parametric analysis was carried out, and the influences of the following parameters were investigated: (i) cavity aspect ratio, (ii) turbulence level of the oncoming flow, and (iii) Reynolds number. A finite-difference computer code was used to integrate the incompressible Reynolds-averaged Navier–Stokes equations. The code, recently developed by the authors, is of the pressure-based type, the grid is collocated, and artificial smoothing terms are added to control eventual odd–even decoupling and nonlinear instabilities. The parametric study revealed and helped to clarify many important physical aspects. Among them, the so called “vortexes encapsulation,” a desirable effect, because the capsule works well as a kind of fluidic thermal insulator. Another important point is related to the role played by the turbulent diffusion in the heat transfer mechanism.

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