Thermal Void

Use the Thermal Void load to define the fluid material, its heat load, and its capacitance. You can define a single Thermal Void load that references up to 20 void regions which define the pressure and heat transfer characteristics of each region.

In the void region, you do the following:

• Select the model surface or edge that is convecting.

• Define the pressure at the model boundary.

• Define heat transfer characteristics.

• Define the area correction for internal edges that have different thicknesses on either side.

• Account for swirl effect in heat transfer due to rotating machinery.

All void regions of each thermal void load must have the same temperature reference frame. A void region can have either the relative temperature reference frame or the absolute temperature reference frame.

If you want to use the relative temperature reference frame, set Rotational Effects to Relative Temperature Reference Frame. If you want to use the absolute temperature reference frame, set Rotational Effects to either Neglect Wall Rotation or Correct for Wall Rotation.

Example:

If you set Rotational Effects to Relative Temperature Reference Frame in one void region of a thermal void load, then all void regions of the same thermal void load must also have their Rotational Effects set to Relative Temperature Reference Frame.

Supported variables and functions

The following table lists the independent variables and auto-generated expressions for the Thermal Void and Void Region quantities that you can define using fields and expressions.

Quantity	Variables	Auto-generated expressions
Heat Load	Thermal CapacitanceTimeTemperature	fluid_temperatureheat_flow_ratemass_flow_ratenxnynzpressureradiusrotational_speedtemperaturetemperature_differencethermal_capacitancethicknesstimexyz
Capacitance****Volume	TimeTemperature
Pressure	TimeSpatial variablesTime, spatial variables
Heat Transfer CoefficientArea Correction FactorArea Override	TimeTemperatureHeat flow rateTemperature differenceThermal capacitanceSpatial variablesNOTETime, spatial variablesNOTETemperature, spatial variablesNOTETemperature difference, spatial variablesNOTE	fluid_temperaturegap_distanceheat_flow_ratemass_flow_ratenxnynzpressureradiusrotational_speedtemperaturetemperature_differencethermal_capacitancethicknesstimexyz
Swirl VelocitySwirl RatioRelative Temperature Difference	TimeSpatial variablesTime, spatial variables	contact_pressurefluid_temperaturegap_distanceheat_flow_ratemass_flow_ratenxnynzpressureradiusrotational_speedtemperaturetemperature_differencethermal_capacitancethicknesstimexyz

You can also use the built-in functions that are listed in Mathematical functions in expressions and Thermal-flow functions in expressions.

Where do I find it?

Application	Pre/Post
Command Finder	Thermal Void
Simulation Navigator	Right-click the Load Container node→New Load→Thermal Void

Learn more

Working with reusable regions

Inputs to expressions

Displaying data summary in HTML

Look up more details

Total temperature effects

Multiple Fluid materials

Auto-generated expressions

HTML summary data

Quick links

Simcenter 3D Thermal/Flow, Electronic Systems Cooling, and Space Systems Thermal boundary conditions

Thermal/Flow, Electronic Systems Cooling, and Space Systems Thermal

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

Browse Simcenter 3D help by product area

Thermal Void, Simcenter 3D 2021.1 Series

© 2020 Siemens

N/A for area override.

N/A for area override.

N/A for area override.

N/A for area override.

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