Characteristics of mixed convection heat transfer in a lid-driven square cavity with various Rich (original) (raw)
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Mixed Convection of Heat Transfer in a Square Lid-Driven Cavity
International Letters of Chemistry, Physics and Astronomy, 2015
Three dimensional steady state mixed convection in a lid driven cubical cavity heating from below has been investigated numerically. Two sided walls are maintained at a constant ambient temperature Ttop > Tbottom, while the vertical walls are thermally insulated. Governing equations expressing in a dimensionless form are solved by using finite element method. The Reynolds number is fixed at Re=100, while the Richardson number is varied from 0.001 to 10. Parametric studies focusing on the effect of the Richardson number on the fluid flow and heat transfer have been performed. The flow and heat transfer characteristics, expressed in terms of streamlines, isotherms and average wall Nusselt number are presented for the entire range of Richardson number considered. Multiple correlations in terms of the heat transfer rate and Richardson number has been established.
Mixed convection in two-sided lid-driven differentially heated square cavity
International Journal of Heat and Mass Transfer, 2004
This study aims to analyze mixed convection in a square cavity with two moving vertical walls by finite volume method. The cavity filled with Non-Newtonian fluid of Bingham model is heated from below and cooled by the other walls. This study has been conducted for certain parameters of Reynolds number (Re=1-100), Richardson number (Ri=1-20), Prandtl number (Pr=1-500), and Bingham number has been studied from 0 to 10. The results indicate that the increase in yield stress drops the heat transfer and the flow become flatter, while increasing Reynolds number augments it. The convective transport is dominant when increasing Richardson number which leads to enhance heat transfer in the cavity for both Newtonian and Non-Newtonian fluid. A correlation of Nusselt number is given in function of different parameters.
Numerical Investigation of a Mixed Convection Flow in a Lid-Driven Cavity
American Journal of Computational Mathematics, 2016
This study is devoted to the computational fluid dynamics (CFD) modeling of steady laminar mixed convection flow and heat transfer in lid driven cavity (10 ≤ Re ≤ 1000). The ratio of the height to the width of the cavity is ranged over H/L = 0.5 to 1.5. The governing equations are solved using commercial finite volume package FLUENT to visualize the nature of the flow and estimate the heat transfer inside the cavity for different aspect ratio. The simulation results are presented in terms of average Nusselt number of the hot wall, velocity profile, and temperature contours. It was found that the average Nusselt number inside the cavity is strongly governed by the aspect ratio as well as the Reynolds number. A parametric study is conducted to demonstrate the effect of aspect ratio on the flow and heat transfer characteristics. It is found that heat transfer enhancement was obtained by decreasing the aspect ratio and/or increasing the Reynolds number.
MATEC Web of Conferences, 2020
In the present work, laminar mixed convection of a Newtonian fluid around a hot obstacle in a square cavity with moving vertical walls is studied numerically. The objective of this study is to analyze the effect of the Richardson number (0 ≼ Ri ≼ 10) and Reynolds number (50 ≼ Re ≼ 500) on both hydrodynamic and thermal characteristics around a hot obstacle in the enclosure. The analysis of the obtained results shows that the heat transfer is enhanced for high values of Richardson and Reynolds numbers.
International Journal of Thermal Sciences, 2012
In this article, numerical investigation is carried out for mixed convection heat transfer within square cavities for various thermal boundary conditions on bottom and side walls based on thermal aspect ratio (A). A penalty finite element analysis with bi-quadratic elements has been used to investigate the results in terms of isotherms, streamlines, heatlines and average Nusselt numbers for a wide range of parameters (1 Re 100, 0.015 Pr 10, 10 3 Gr 10 5). A detailed analysis of flow pattern shows that natural convection or forced convection depends on both parameters: Ri (Ri ¼ Gr/Re 2) and Pe (Pe ¼ Re$Pr). Results indicate that, at low Pr (Pr ¼ 0.015) with low Gr (Gr ¼ 10 3), isotherms are decoupled with flow profile and conduction dominant heat transfer is observed irrespective of Re, due to low Peclet number. At Gr ¼ 10 3 , lid-driven force dominates and the non-symmetric flow distribution occurs irrespective of Re (1,10 and 100), Pr (0.015, 0.7 and 10) and thermal aspect ratio (0.1, 0.5 and 0.9). At Gr ¼ 10 5 with Re ¼ 1, natural convection dominates the flow irrespective of Pr and A. Considerably smaller dominance of liddriven force is observed over buoyancy force at Gr ¼ 10 5 with Re ¼ 10 irrespective of Pr for A ¼ 0.1 and 0.5, whereas strong effect of lid-driven force is found at Gr ¼ 10 5 with Re ¼ 100 irrespective of Pr and A. Multiple circulations are found in streamlines and heatlines especially for A ¼ 0.5 and 0.9 at high Reynolds number (Re ¼ 100) with Pr ¼ 10 and Gr ¼ 10 5. It is found that, streamlines and heatlines circulation cells follow qualitatively similar pattern for higher Pr (Pr ! 0.7) at Gr ¼ 10 5 irrespective of Re. Thermal gradient is found to be high at the center of the bottom wall for A ¼ 0.1 due to highly dense heatlines at that zone whereas that is low for A ¼ 0.9 irrespective of Re, Pr and Gr. It is also found that, as thermal aspect ratio increases, the average Nusselt number decreases for Pr ¼ 0.015 and Pr ¼ 0.7 irrespective of Re. Finally, it is concluded that overall heat transfer rates are higher for A ¼ 0.1 as compared to other thermal aspect ratios (A ¼ 0.5, A ¼ 0.9) irrespective of Pr (0.015 Pr 10), Re (1 Re 100) and Gr (10 3 Gr 10 5).
The present study has been conducted to numerically investigate the heat and mass transport mechanism of laminar mixed convection in a shear- and buoyancy-driven cavity subjected to differential heating and differential species concentration. The focus is on the interaction of the forced convection induced by the moving sidewalls with the natural convection induced by the buoyancy. Two orientations of the direction of the moving walls at the cavity are considered in order to simulate the aiding and opposing buoyancy mechanisms. The two-dimensional transport equations for continuity, momentum, energy and species transfer are solved using the finite element formulation based on the Galerkin method of weighted residuals. Parametric studies of the effect of the mixed convection parameter, Richardson number on the fluid flow and heat and mass transfer have been performed. It is found that both Richardson number and the direction of moving walls affect the fluid flow and heat and mass transfer in the cavity. In addition, the predicted results for the average Nusselt and Sherwood numbers are presented and discussed for various parametric conditions.
Unsteady simulations of mixed convection heat transfer in a 3D closed lid-driven cavity
International Journal of Heat and Mass Transfer, 2016
Unsteady mixed convection heat transfer in a 3D closed cavity with constant heat flux on the centre part of the bottom wall and isothermal sidewalls moving in the same vertical direction is investigated numerically in this research. The other remaining walls forming the geometry are kept stationary and adiabatic. This research is accomplished with different Reynolds number, Re = 5000, 10000, 15000 and 30000. Numerical methodology based on the finite volume method is utilized. The simulations and analysis have been carried out by evaluating the performance of two turbulence methods, Unsteady Reynolds-Averaged Navier-Stokes (URANS) and Large Eddy Simulation (LES), in terms of flow vectors, isotherm contours, turbulent kinetic energy, the average Nusselt number (Nuav) and the local Nusselt (Nulocal) number along the hot part of the bottom wall. The results show that by increasing the Reynolds number leads to enhanced Nusselt number and turbulent kinetic energy of the fluid in the domain. Moreover, both LES and URANS solutions captured the existence of the two primary vortexes (clockwise and anticlockwise). However, the comparisons have demonstrated clearly the ability and accuracy of the LES method in predicting the secondary vortexes in the corners of the cavity.
International Journal of Mechanical and Materials Engineering, 2010
The fluid flows and heat transfer induced by the combined effects of mechanically driven lid and buoyancy force within a rectangular cavity is investigated in this paper numerically. The horizontal walls of the enclosure are insulted while the right vertical wall is maintained at a uniform temperature higher than the left vertical wall. In addition, it contains a heat conducting horizontal circular block in its centre. The governing equations for the problem are first transformed into a non-dimensional form and the resulting nonlinear system of partial differential equations are solved by using the finite element formulation based on the Galerkin method of weighted residuals. The analysis is conducted by observing the variations of streamlines and isotherms for different Reynolds number and Prandtl number ranging from 50 to 200 and from 0.071 to 3.0 respectively. The results indicated that both the streamlines and isotherms strongly depend on the Reynolds number and Prandtl number. Moreover, the results of this investigation are also illustrated by the variations of average Nusselt number on the heated surface and average fluid temperature in the enclosure.
Mixed Convection in a Lid-Driven Cavity with Internal Heat Source
Steady state two-dimensional mixed convection problem in a square enclosure has been studied numerically. The top moving lid of the cavity and the bottom wall is maintained at constant temperature, while the vertical walls are thermally insulated. Forced convection arises from the sliding of the upper lid whereas natural convection is due to internal heating sources, which are assumed to be uniformly distributed within the enclosure. The computational procedure is based on Galerkin finite element method. Parametric studies of the effect of the mixed convection parameter, Richardson number on the fluid flow and heat transfer have been performed. Flow and heat transfer characteristics, streamlines, isotherms and average wall Nusselt number are presented for whole range of Richardson number considered