Numerical study of flow and thermal behaviour of lid-driven flows in cavities of small aspect ratios

Abstract

SUMMARYNumerical study has been performed to investigate the e ects of cavity shape on ow and heat transfer characteristics of the lid-driven cavity ows. Dependence of ow and thermal behaviour on the aspect ratio of the cavities is also evaluated. Three types of the cross-sectional shape, namely, circular, triangular, and rectangular, and four aspect ratios, 0:133; 0:207; 0:288, and 0.5, are taken into account to construct twelve possible combinations; however, attention is focused on the small-aspect-ratio situations. Value of the Reynolds number considered in this study is varied between 100 and 1800. For the cases considered in this study a major clockwise vortex driven by the moving lid prevailing in the cavity is always observed. When the Reynolds number is ÿxed, the rectangular cavity produces strongest lid-driven ow, and the triangular cavity weakest. For the cases at small aspect ratio and low Reynolds number, the streamlines appear symmetric fore-and-aft with respect to the central line at x=L = 0:5. Data for the local and average Nusselt numbers are also provided. For rectangular cavities, it is observed that case 1=5R produces the highest average Nusselt number at any Reynolds number. Among the twelve possible geometric cases considered herein, the highest and lowest average Nusselt numbers are found with cases 1=6T and 1=2C, respectively.

Effects of Aspect Ratios on Flow Friction and Thermal Behavior Inside a Close Domain Using Lattice Boltzmann Method

“…The validation of present simulation has been shown against the numerical results of Chen et al [4]. The variation of average heat transfer rate in terms of Nusselt number, Nu, for different values of Reynolds number on the moving lid of the triangular enclosure with AR=2.0 is illustrated in Fig.2 It can be seen from the above figure that our present LBM simulations are in very good agreement with numerical solutions of finite-volume method obtained by Chen at al.…”

“…The variation of average heat transfer rate in terms of Nusselt number, Nu, for different values of Reynolds number on the moving lid of the triangular enclosure with AR=2.0 is illustrated in Fig.2 It can be seen from the above figure that our present LBM simulations are in very good agreement with numerical solutions of finite-volume method obtained by Chen at al. [4]. It is noted that, for verification of our method the top moving lid is maintained at cold temperature while the lower two inclined walls are uniformly heated.…”

“…Actually, the Nusselt number, Nu, is a dimensionless form of the heat transfer coefficient. To investigate the heat transfer performance in terms of effective thermal conductivity of the fluid, the local Nusselt number, Nu x, is defined by Chen et al [4].…”

“…In most geophysical flows, the temperature difference is the driving mechanism of the motion of the fluid. From a practical point of view, the research on natural, force and mixed convections in a cavity of various shapes with different boundary conditions and numerical techniques are extensively discussed by many researchers [1][2][3][4][5]. Moreover, to the experimental and theoretical investigations, various computational methods are used to study the fluid flow and heat transfer in close domain like cavity flow.…”

Axial piston pump grooved slipper analysis by CFD simulation of three-dimensional NVS equation in cylindrical coordinates

“…The literature available for pressure/flow simulation in cavities is quite vast and the SIMPLE (semi implicit method for pressure linked equation) family algorithm [27] has been widely applied to this kind of simulation. Most of the work has been done for rectangular cavities [28][29][30][31][32][33][34] where Cartesian coordinates were applied. Literature available on cavities in cylindrical coordinates [35][36][37] is much less common.…”