fluentv热交换.pptVIP

Heat Transfer Modeling Introductory FLUENT Training Outline Energy Equation Wall Boundary Conditions Conjugate Heat Transfer Thin and two-sided walls Natural Convection Radiation Models Reporting - Export Energy Equation – Introduction Energy transport equation: Energy E per unit mass is defined as: Pressure work and kinetic energy are always accounted for with compressible flows or when using the density-based solvers. For the pressure-based solver, they are omitted and can be added through the text command: Define/models/energy? Energy Equation Terms – Viscous Dissipation Energy source due to viscous dissipation: Also called viscous heating. Important when viscous shear in fluid is large (e.g. lubrication) and/or in high-velocity compressible flows. Often negligible Not included by default in the pressure-based solver. Always included in the density-based solver. Important when the Brinkman number approaches or exceeds unity: Energy Equation Terms – Species Diffusion Energy source due to species diffusion included for multiple species flows. Includes the effect of enthalpy transport due to species diffusion Always included in the density-based solver. Can be disabled in the pressure-based solver. Energy Equation Terms (3) Energy source due to chemical reaction is included for reacting flows. Enthalpy of formation of all species. Volumetric rate of creation of all species. Energy source due to radiation includes radiation source terms. Interphase energy source: Includes heat transfer between continuous and discrete phase DPM, spray, particles… Energy Equation for Solid Regions Ability to compute conduction of heat through solids Energy equation: h is the sensible enthalpy: Anisotropic conductivity in solids (pressure-based solver only) Wall Boundary Conditions Five thermal conditions Radiation Heat transfer from exterior of model Requires external emissivity