Free convectio in porous media在多孔介质中的自然对流.pptVIP

Free Convection in Porous Media Introduction This model exemplifies the use of COMSOL Multiphysics for modeling of free convection in porous media. It shows the following COMSOL Multiphysics features: Porous media flow Multiphysics between fluid flow and heat transfer Results that are in excellent agreement with published models in the research journals in the field The model has applications mainly in the fields of: Geophysics Chemical engineering Geometry, Heating and Cooling Surfaces Enclosed domain with porous material The walls of the domain are impervious to flow The walls are either heating or cooling surfaces with linear temperature profiles uniting the cool and hot surfaces The arc length s goes from zero to 1 along a boundary segment. Domain Equations Brinkman equations for porous media flow Convection and conduction Boundary Conditions Results Concluding Remarks The model is simple to define and solve in COMSOL Multiphysics The results give excellent agreement with published scientific papers, see M. Anwar Hossain and Mike Wilson, Natural convection flow in a fluid-saturated porous medium enclosed by non-isothermal walls with heat generation, International Journal of Thermal Sciences, Int. J. Therm. Sci. 41 (2002) 447–454. * Th-(Th-Tc)*s Tc Tc Th Th-(Th-Tc)*s Momentum and mass balances Heat balance Boussinesq buoyant lifting term links flow and heat p = pressure u = vector of directional velocities h = dynamic viscosity k = permeability r = fluid density g = gravity bT = thermal expansion coefficient T = temperature from heat transfer application Tc = initial temperature Solution technique: Parametric solver to increase bT from zero to problem- specific value T = temperature Ke = effective thermal conductivity of fluid and solid medium CL = fluid volumetric heat capacity… CL= cp r cp = fluid specific heat capacity u = vector of directional fluid velocities from flow application Brinkman equations for unique solution fix pressure at a point