ANSYS 12.0 官方培训手册-Introduction to CFX-PART A.pptVIP

Area Porosity Fraction of physical area that is available for the flow to go through Always assumed Isotropic Selections on Domains panel affect which options are available on other panels There can be any combination of fluid, solid, and porous domains which can be included in the CHT (Conjugate Heat Transfer) simulation * * Area Porosity Fraction of physical area that is available for the flow to go through Always assumed Isotropic * Inlets and Outlets Inlets are used predominantly for regions where inflow is expected; however, inlets also support outflow as a result of velocity specified boundary conditions Velocity specified inlets are intended for incompressible flows Using velocity inlets in compressible flows can lead to non-physical results Pressure and mass flow inlets are suitable for compressible and incompressible flows The same concept applies to outlets Velocity Specified Condition Pressure or Mass Flow Condition Inlet Inlet Inflow allowed Inflow allowed Outflow allowed Openings Artificial walls are not erected with the opening type boundary, as both inflow and outflow are allowed You are required to specify information that is used if the flow becomes locally inflow Do not use opening as an excuse for a poorly placed boundary See the following slides for examples Pressure Specified Opening Inlet Inflow allowed Outflow allowed Symmetry Used to reduce computational effort in problem. No inputs are required. Flow field and geometry must be symmetric: Zero normal velocity at symmetry plane Zero normal gradients of all variables at symmetry plane Must take care to correctly define symmetry boundary locations Can be used to model slip walls in viscous flow symmetry planes Fuel Air Manifold box 1 Nozzle 1 2 3 Specifying Well Posed Boundary Conditions 1 Upstream of manifold Can use uniform profiles since natural profiles will develop in the supply pipes Requires more elements Nozzle inlet plane Requires accurate velocity profile data for th