Thermal¶

THERMAL solves steady-state heat conduction, in 3D under a solid frame, on the r-z half-plane under an axisymmetric frame and on a planar section under a Cartesian 2D frame. See Conditions and physics for how conditions attach and where they land.

Frame	Solves as	Solver stack
Solid	`THERMAL`	HeatSolver, SaveScalarsSolver, ResultOutputSolver
Axisymmetric	`THERMAL`	HeatSolver, SaveScalarsSolver, ResultOutputSolver
Cartesian2D	`THERMAL`	HeatSolver, SaveScalarsSolver, ResultOutputSolver

Boundary conditions¶

Condition	Target	Sets	Frames
`FixedTemperature`	boundary	`value` [K]	Solid, Axisymmetric, Cartesian2D
`HeatFlux`	boundary	`value` [W/m²]	Solid, Axisymmetric, Cartesian2D
`Convection`	outer shell	`coefficient` [W/(m²·K)], `ext_temperature` [K]	Solid, Axisymmetric, Cartesian2D

A thermal solve needs at least one boundary condition, or the sif writer warns that the solve is likely ill-posed.

FixedTemperature¶

Physics THERMAL · Target boundary · Section Boundary Condition · Kind fixed_temperature · API FixedTemperature

A fixed temperature on a boundary.

Field	Symbol	Unit	Meaning	Sif keyword	Default
`value`	`T`	K	Fixed temperature imposed on the boundary.	`Temperature`	required

HeatFlux¶

Physics THERMAL · Target boundary · Section Boundary Condition · Kind heat_flux · API HeatFlux

A prescribed heat flux through a boundary.

Field	Symbol	Unit	Meaning	Sif keyword	Default
`value`	`q_s`	W/m²	Heat flux through the boundary.	`Heat Flux`	required

Convection¶

Physics THERMAL · Target outer shell · Section Boundary Condition · Kind convection · API Convection

Newton cooling of an outer surface to an ambient temperature.

Field	Symbol	Unit	Meaning	Sif keyword	Default
`coefficient`	`h`	W/(m²·K)	Convective heat-transfer coefficient.	`Heat Transfer Coefficient`	required
`ext_temperature`	`T_amb`	K	External (ambient) temperature the boundary exchanges with.	`External Temperature`	required

Body forces¶

Condition	Target	Sets	Frames
`HeatSource`	body	`power_density` [W/m³], `temperature_coefficient` [1/K], `reference_temperature` [K]	Solid, Axisymmetric, Cartesian2D

HeatSource¶

Physics THERMAL · Target body · Section Body Force · Kind heat_source · API HeatSource

A volumetric heat source in a body.

Field	Symbol	Unit	Meaning	Sif keyword	Default
`power_density`	`q`	W/m³	Heat generation density at `reference_temperature` when a coefficient is set, else the constant source.	`Volumetric Heat Source`	required
`temperature_coefficient`	`α`	1/K	Linear coefficient in q(T) = power_density·(1 + α·(T − reference_temperature)); None emits the constant.		`None`
`reference_temperature`	`T_ref`	K	The temperature `power_density` holds at; required with `temperature_coefficient`.		`None`

Writes: The Volumetric Heat Source keyword, a MATC expression in temperature when temperature_coefficient is set.