Flow In Rectangular Enclosure Research Articles

Analogy between thermal and mass diffusion effects of a free convective flow in rectangular enclosure

Journal of Applied Mathematics and Computational Mechanics, Prace Naukowe Instytutu Matematyki i Informatyki, Politechnika Częstochowska, Scientific Research of the Institute of Mathematics and Computer Science, Czestochowa University of Technology

Experimental and numerical study of Buoyancy-driven low turbulence flow in rectangular enclosure partially filled with isolated solid blockages

This paper considers the natural convection inside an air filled enclosure having several isolated cylindrical blockages distributed within it, and arranged parallel to two vertical walls of the enclosure. These two walls are maintained at different temperatures resulting in a natural convection process inside the enclosure. The objectives are to provide experimental temperature data and to investigate the influence of the blockages proximity within and outside the active vertical wall hydrodynamic boundary layer of the natural convection flow and heat transfer. Experiments were designed with high degree of accuracy to provide reliable temperature data-bank for a range of blockages proximity to the active vertical walls. The test enclosure is an air filled rectangular cavity fixed at 0.97 m × 0.4 m × 1 m, corresponding to the height, width and depth respectively. The top and bottom walls are conducting surface and the temperature difference between the active vertical walls was maintained at 42.2 °C resulting in a characteristic Rayleigh number of 4.04 × 109 based on the enclosure height. All the walls of the enclosure were insulated externally while the inner surfaces were covered with conducting plate. The test cavity capability of establishing low turbulence natural convection flows was verified. All temperature data were obtained at steady state and it was verified to be reproducible by repeating the experiment at different times. Also, two-dimensionality was verified via rigorous temperature readings over a period of time. Additional temperature readings were recorded for the air and cylinder surfaces at several distinct locations. Further investigations were conducted using a numerical approach to supplement and validate the experiments.Experimental temperature data collated at various locations within the enclosure show excellent comparison with numerical results and as such provide a useful experimental benchmark temperature data for the validation of low turbulence natural convection flow in enclosure partially filled with isolated solid objects. Our result shows that a significant increment or reduction in air temperature and wall heat transfer could be achieved by varying the blockages proximity, and especially when the blockages are positioned within the hydrodynamic boundary layers of the active vertical walls.

Numerical simulation of double-diffusive mixed convective flow in rectangular enclosure with insulated moving lid

The present study is concerned with the mixed convection in a rectangular lid-driven cavity under the combined buoyancy effects of thermal and mass diffusion. Double-diffusive convective flow in a rectangular enclosure with moving upper surface is studied numerically. Both upper and lower surfaces are being insulated and impermeable. Constant different temperatures and concentration are imposed along the vertical walls of the enclosure, steady state laminar regime is considered. The transport equations for continuity, momentum, energy and spices transfer are solved. The numerical results are reported for the effect of Richardson number, Lewis number, and buoyancy ratio on the iso-contours of stream line, temperature, and concentration. In addition, the predicted results for both local and average Nusselt and Sherwood numbers are presented and discussed for various parametric conditions. This study was done for 0.1 ≤ Le ≤ 50 and Prandtl number Pr = 0.7. Through out the study the Grashof number and aspect ratio are kept constant at 10 4 and 2 respectively and −10 ≤ N ≤ 10, while Richardson number has been varied from 0.01 to 10 to simulate forced convection dominated flow, mixed convection and natural convection dominated flow.