The Numerical Study On Natural Convection And Heat Transfer In Square Composite Porous/Fluid Cavity

In the composite system of porous media and fluid, fluid flow, heat and mass transfer phenomena prevail in nature and practical engineering such as grain drying, building enclosure, insulation materials, groundwater pollution, the use of nuclear energy, micro-electronic technology and so on. According to its wide existence in nature and engineering application as well as its complex mechanism, the study plays a significant role in science and technology development. Despite of the deep respective study on natural convection and heat transfer within the porous medium and the pure fluid region, little study has been made on the composite cavity with porous media and pure fluid. At the same time taking the limitation of testing technology into account, less study focused on natural convection and heat transfer. However, In practical engineering, there are many problems involved in the composite cavity, as a result, more focus are required on the fluid flow, heat and mass transfer in the composite cavity to provide applicable guidance.In this paper, through the theoretical analysis, numerical simulation and experiments as the solution methods, taking account of the influences of the stress slip condition at the interface between porous medium and pure fluid and mainly discussing about the law of fluid flow and heat transfer in the composite cavity with the existing temperature gradient.In the case of the co-existence of temperature field, took simulation and analysis under different working conditions, and then got the basic rule of the natural convection in the complex cavity, showed the changing situation of the flow field, temperature field with characteristic parameters such as the thickness of porous media d, Rayleigh number Ra, Darcy number Da, the interface stress slip factor/β1 andβ2 and so on, and discussed the effect law of these characteristic parameters on the wall heat.Based on theoretical analysis and numerical simulation, constructed a compound cavity fluid flow bench, formed a natural convection in the body cavity by the way of supplying a horizontal temperature gradient adopted two-dimensional particle image velocimetry PIV technology to test the flow fielc under different Ra number.The factors influencing the natural convection in the composite cavity partially fillec with porous media are so many that the law is very complicated. This paper mainly studied the effect attributes of the porous medium parameters (porous layer thickness d, Darcy number Da), Rayleigh number Ra and the stress slip coefficients at the porous media/fluid interface (the first stress slip coefficientβ1, the second stress slip coefficientβ2), and got the effect law of all parameters on heat and mass transfer, which laid a theoretical foundation for the research of heat and mass transfer in composite cavity.