Heat Transfer Model
Heat transfer plays a significant role across a wide range of engineering applications. The change in temperature governs a material’s properties and determines how and when it changes phase. In hydraulic flows, this results in the buoyant motion of a thermal plume ejecting into a river or the freezing of a storage tank in winter. For metal casting, additive manufacturing, and welding, proper management of the transfer of heat determines how and where defects form and the thermal loads present.
The FLOW-3D product family accounts for the conduction, convection, and radiation within and between all three phases (fluid, solid, and void/gas) by solving the full conjugate heat transfer equations. The Heat Transfer Model forms the thermal foundation on which phase change, solidification, die cycling, spray cooling, and thermal stress models all depend.
Modeling Capabilities
The Heat Transfer Model solves energy transport equations simultaneously in fluid and solid domains, with heat exchange at every fluid-solid interface computed automatically. This means thermal gradients in a die wall due to spray cooling, the transient heat buildup during repeated casting cycles, and the temperature-dependent solidification of a melt are all resolved in a single simulation without manual coupling between separate solvers.
Heat transfer coefficients between different media can be either specified directly or calculated automatically based on the local flow conditions. A wide variety of boundary conditions are available to precisely control how heat enters and leaves a domain: specified heat flux, power source, prescribed temperature, convective heat transfer to an external environment, and radiative heat exchange with surrounding surfaces and voids. These thermal inputs can be controlled via Active Simulation Control.
Material properties such as density, viscosity, thermal conductivity, and surface tension can be specified in tabular form. This eliminates the need to fit experimental data to analytical functions, allowing complex, non-linear property dependencies to be represented directly from laboratory measurements.
Temperature distribution in an aluminum HPDC casting during mold filling, showing conjugate heat transfer between the melt and surrounding die geometry.
Phase Change
The Heat Transfer Model is the foundation for all phase change processes in the FLOW-3D product family. Liquid-solid phase change governs metal solidification and melting in casting, additive manufacturing, and welding applications. Liquid-vapor phase change governs boiling, evaporation, spray cooling, and cryogenic propellant behavior. Both phase change modes are tightly coupled to the energy transport equations so that latent heat, temperature-dependent solidus and liquidus lines, and enthalpy changes are all accounted for consistently.
Viscous Heating
In high-speed viscous flows, the dissipation of kinetic energy into heat can be significant. Viscous heating can be included in the energy transport equation for applications where this effect matters, such as polymer processing, high-speed lubrication flows, and non-Newtonian fluid handling.
Applications
The Heat Transfer Model is used across the FLOW-3D product family for:
- Metal casting thermal analysis, die temperature distribution, and thermal die cycling
- Additive manufacturing melt pool thermal evolution, heat affected zone prediction, and layer-by-layer thermal accumulation
- Laser welding thermal fields, keyhole dynamics, and heat affected zone characterization
- Spray and jet cooling of hot surfaces in industrial thermal management applications
- Buoyancy-driven flows in environmental and process engineering applications
- Boiling, evaporation, and condensation in chemical process and energy system modeling
- Conjugate heat transfer in heat exchangers, electronic cooling, and thermal management devices
- Cryogenic propellant tank pressurization and thermal stratification
- Heating, Ventilation, and Air Conditioning
Metal temperature during mold filling of a large HPDC structural component. The conjugate heat transfer model tracks thermal exchange between the melt and die simultaneously, enabling accurate prediction of cold shut risk and thermal conditions at end of fill.