# ThermalProperties

Material thermal properties. This section is available when the current task group includes a Heat solver. A standalone FDTD task does not show it; a coupled task group can show it while the same medium is shared with FDTD.

The editor shows Medium Type and, for SolidSpec, Thermal conductivity. The fluid properties and the solid capacity and density fields below are API fields; the editor does not provide inputs for them.

A new medium in a heat simulation starts with SolidSpec. In other simulations, no heat specification is attached until you add one.

# Medium Type

type: Selects the thermal model in the medium settings.

Type: string

Options:

  • FluidSpec
  • SolidSpec

Default: SolidSpec in a heat simulation; no heat specification otherwise.

# Fluid Medium

When setting the medium as FluidSpec, the heat solver equation will not be calculated in the regions with that medium.

# Fluid Properties

Fluid thermal properties are available for FluidSpec through the Python interface.

thermal_conductivity: Fluid thermal conductivity.

Type: floating-point number

  • Unit: W/(μm·K)
  • Constraint: greater than or equal to 0
  • Default: None

viscosity: Fluid dynamic viscosity.

Type: floating-point number

  • Unit: kg/(μm·s)
  • Constraint: greater than or equal to 0
  • Default: None

specific_heat: Fluid specific heat.

Type: floating-point number

  • Unit: μm²/(s²·K)
  • Constraint: greater than or equal to 0
  • Default: None

density: Fluid density.

Type: floating-point number

  • Unit: kg/μm³
  • Constraint: greater than or equal to 0
  • Default: None

expansivity: Fluid thermal expansivity.

Type: floating-point number

  • Unit: 1/K
  • Constraint: greater than or equal to 0
  • Default: None

# Solid Medium

conductivity: Thermal conductivity of the material.

Type: floating-point number

  • Unit: W/(μmK)W/(\mu m\,K)
  • Constraint: greater than 0
  • Required field

capacity: Heat capacity.

Type: floating-point number

  • Constraint: greater than 0
  • Unit: J/(kg·K)
  • Default: 1 for SolidSpec

density: Material density.

Type: floating-point number

  • Constraint: greater than 0
  • Unit: kg/μm³
  • Default: None

NOTE

When you create a medium in a Heat simulation, the editor initializes capacity to 1. To set capacity, density, or the fluid properties, use the Python interface.