FLOW-3D孔介质模型-渗流模型.pptxVIP

第四章、FLOW-3D 多孔介质模型FLOW-3D? v9.4Examples of Porous MediaSpongeStreambedWire ScreenTube BundlePaperSinter Metal FilterUser TrainingTypes of Porous Objects in FLOW-3DPorous componentsRequire 2 computational cells to adequately resolveModel object as component ifSignificant gradients occur through thickness of materialMaterial is anisotropicPorous material may beIsotropic (e.g. bed of uniform particles)Anisotropic (e.g. tube bundles)Porous baffles No thickness, reside on cell facesBest for modeling screensDrag can be linear or quadraticModel assumes baffle is saturated, no bubble pressure acrossUser Training Porous Media ModelingTheoryList of topics 介绍达西定律（Darcy law）介绍 FLOW-3D?拖曳力模型(drag model)介绍饱和多孔介质模型 (the saturated porous media model)介绍拖曳力系数与渗透率的关系 (drag coefficient and permeability)如何处理流体在多孔介质中的各向异性(anisotropy)特征介绍非饱和多孔介质模型 (the unsaturated porous media model)达西定律（Darcy Law）Q : units of volume per time (e.g., m3/s)A : cross-sectional area( Pb ? Pa ) : the pressure drop μ : dynamic viscosityΚ : the /wiki/Permeability_(fluid)permeability of the medium (units of area, e.g. m2) L : the lengthViscous Drag in Porous Media: Darcy’s LawDarcy’s Law: Flow rate through porous media is proportional to pressure drop according to:where v = macroscopic (superficial) velocity (FLOW-3D computes and reports microscopic velocity) K = intrinsic permeability - may be isotropic or anisotropic (directional) m = dynamic viscosity P = fluid pressurePermeabilityProperty of the porous materialRepresents the average resistance to flow in a control volumeDarcy’s law represents viscous losses through poresApplicable when pore Reynolds number Rep ~ 1, where Rep = Applies well to tightly packed spheres and fibersDoes not represent inertial losses in loosely packed bedsInertial Losses: Forchheimer’s Equation Inertial drag becomes significant when Rep exceeds 10Darcy’s Law can be extended to include inertial effectsQuadratic drag: Forchheimer’s Equationwhere r = fluid densityviscoustransitionalin