Mixed convection in two-sided lid-driven differentially heated square cavity (original) (raw)
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Mixed Convection of Bingham Fluid in a Two Sided Lid-Driven Cavity Heated From Below
Fluid Dynamics & Materials Processing
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.
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 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
Characteristics of mixed convection heat transfer in a lid-driven square cavity with various Rich
In mixed convection flows, a common knowledge is that the heat transfer in a cavity is increased with increasing Grashof or Reynolds number when its respective Reynolds or Grashof number is kept at constant. On the other words, the heat transfer would increase if the flow proceeds toward pure natural convection or forced convection dominated regimes. An unanswered question is that would the heat transfer be increased continuously with simultaneously increasing both Grashof and Reynolds numbers, while keeping the Richardson and Prandtl numbers constant. And to what extent the mixed convection flows would change from laminar to chaos. These questions motivate the present study to systematically investigate the flow and heat transfer in a 2-D square cavity where the flow is induced by a shear force resulting from the motion of the upper lid combined with buoyancy force due to bottom heating. The numerical simulations cover a wide range of Reynolds (10 Re 2200), Grashof (100 Gr 4.84 Â 10 6 ), Prandtl (0.01 Pr 50), and Richardson (0.01 Ri 100) numbers. The average Nusselt numbers are reported to illustrate the influence of flow parameter variations on heat transfer, and they are also compared with the reported Nusselt number correlations to validate the applicability of these correlations in laminar flow regimes. Time traces of the total kinetic energy and average Nusselt number are presented to demonstrate the transition of the flows from laminar to chaos.
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.
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.
Boundary Value Problems, 2013
In this study a steady state two-dimensional mixed convection problem in an air filled cavity is investigated. The effects of linearly heated and uniformly cooled walls on flow and heat transfer characteristics within the cavity are determined. The strength of the fluid circulation within the cavity is found for both heated and cooled walls for different Reynolds and Grashof numbers. The nonlinear coupled equations are solved numerically using the penalty-Galerkin finite element method. Stream function and isotherm results are obtained for different Reynolds and Grashof numbers. The results for the heat transfer rate are presented in terms of both the local and the average Nusselt number. In general, the strength of the circulation is stronger for the case of cooled walls, and the anti-clockwise circulation is significantly stronger for cooled walls, while the clockwise circulation is only slightly stronger for the cooled walls and the difference in strength decreases both with increasing Reynolds and Grashof numbers. Both the local and average Nusselt numbers are generally higher for the case of cooled side walls than that for heated side walls. MSC: 34B15; 65N30; 76M20
Mixed convection from a uniform and non uniform sinusoidal heat source on the bottom of a rectangular cavity is studied numerically. Two-dimensional forms of non-dimensional Navier-Stokes equations are solved by using control volume based finite volume technique with staggered grid . Three typical values of the Reynolds numbers are chosen as Re = 10, 100, and 2000 and steady, laminar results are obtained in the values of Richardson number as Ri = 0, 1 and 10, 100 and the values of Prandtl numbers is taken as Pr = 0.71, 7 and 10. The parametric studies for a wide range of governing parameters show consistent performance of the present numerical approach to obtain as stream functions and temperature profiles. Heat transfer rates at the heated walls are presented based on the value of Re and Pr. The computational results indicate that the heat transfer is strongly affected by Reynolds number and Richardson number. In the present investigation, bottom wall is(a) uniformly heated & (b) non –uniformly heated while the two vertical walls are maintained at constant cold temperature and the top wall is well insulated. A complete study on the effect of Ri shows that the strength of circulation increases with the increase in the value of Ri irrespective of Re and Pr. As the value of Ri increases, there occurs a transition from conduction to convection dominated flow at Ri =1. A detailed analysis of flow pattern shows that the natural or forced convection is based on both the parameters Ri and Pr.
Mixed convection in an inclined lid-driven square cavity with sinusoidal heating on top lid
2017
Numerical study on the effect of inclination angle with sinusoidal heating on top moving lid in two-dimensional square cavity is investigated. The top lid is heated sinusoidally while the bottom wall is maintained at cold temperature. The vertical walls are insulated and the cavity is filled with water. Finite volume method and SIMPLE algorithm are employed to solve the dimensionless governing equations. The effect of Richardson number, ranging from 0.1 to 10.0 and inclination angle ranging from 0° to 60° on heat and fluid flow are investigated by utilizing the discretized equations in FORTRAN programming language. The Reynolds number and Prandtl number are fixed. Finally the solutions are discussed using a graphical approach. The results demonstrate that for the case of forced convection and mixed convection dominated regime, heat transfer rate increases with the increase of cavity inclination.
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.