Transient Heat Transfer

Solution methods

• Steady state, linear and/or nonlinear (SOL 153).
• Transient, linear and/or nonlinear (SOL 159).

Heat conduction

• Temperature-dependent conductivity.
• Temperature-dependent specific heat.
• Anisotropic thermal conductivity.
• Latent heat of phase change.
• Temperature-dependent internal heat generation.
• Weighted temperature gradient dependent internal heat generation.
• Time-dependent internal heat generation.
• Free convection boundaries:
• Temperature-dependent heat transfer coefficient.
• Weighted temperature gradient dependent heat transfer coefficient.
• Time-dependent heat transfer coefficient.
• Nonlinear functional forms.
• Weighted film temperatures.

Forced convection

• Tube fluid flow field relationships – H(Re,Pr).
• Temperature dependent fluid viscosity, conductivity, and specific heat.
• Time-dependent mass flow rate.
• Temperature-dependent mass flow rate.
• Weighted temperature gradient dependent mass flow rate.

Radiation to space

• Temperature-dependent emissivity and absorptivity.
• Wavelength dependent emissivity and absorptivity.
• Time-dependent exchange.

Radiation enclosures

• Temperature-dependent emissivity.
• Wavelength-dependent emissivity.
• Diffuse view factor calculations with self and third-body shadowing.
• Adaptive view factor calculations.

Net view factors

• User-supplied exchange factors.
• Radiation matrix control.
• Radiation enclosure control.
• Multiple radiation enclosures.

Applied heat loads

• Directional heat flux.
• Surface normal heat flux.
• Grid point nodal power.
• Temperature-dependent heat flux.
• Weighted temperature gradient dependent heat flux.
• Time-dependent heat flux.
• Temperature boundary conditions:
• Specified constant temperatures for steady state and transient.
• Specified time-varying temperatures for transient.
• Initial conditions:
• Starting temperatures for nonlinear steady state analysis.
• Starting temperatures for all transient analyses.
• Thermal control systems:
• Local, remote, and time-varying control points for free convection heat transfer
  coefficients.
• Local, remote, and time-varying control points for forced convection mass flow rates.
• Local, remote, and time-varying control points for heat flux loads.
• Local, remote, and time-varying control points for internal heat generation rates.
• Transient nonlinear loading functions.
• Perfect conductor algebraic constraint temperature relationships.
• Output graphical display – basic:
• Heat flows for conduction and boundary surface elements.
• Temperature versus time for grid points.
• Enthalpy versus time for grid points.
• Isothermal contour plots.

Miscellaneous

• NX Nastran DMAP and DMAP Alter capability.
• NX Nastran restart capability.
• Direct matrix input to conduction and heat capacitance matrices.
• Lumped mass and discrete conductor representations.