Film Cooling

Use the Film Cooling constraint to implicitly model the cooling of a surface by a fluid film, without modeling all the complex interactions between the environment, the fluid film, and the geometry.

To create a Film Cooling constraint, you must specify the following:

• A convection region that is the cooled surface.

• A film reference region that contains duct elements or duct with mass flow elements. The solver calculates the film temperature from this region.

• The convection coefficient that can vary with time and space.

• The film effectiveness coefficient that can vary with time and space.

• The free stream temperature that can vary with time.

Film cooling schematic	(1) Free stream region with temperature Tfs(2) Fluid film region with temperature Tf(3) Convection region with temperature Tw

The film cooling constraint is similar to the convection to environment constraint, except that the adiabatic wall temperature is computed as a mixture of the free stream temperature, Tfs, and the fluid film temperature, Tf. The heat transfer for a convection region with a Film Cooling constraint is calculated as follows:

Q = h A (ηTf + (1–η)Tfs – Tw)

where:

• h is the specified convection coefficient.

• A is the area of the specified convection region.

• η is the specified film effectiveness coefficient.

• Tw is the surface temperature.

Supported variables and functions

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

Quantity	Variables	Auto-generated expressions
Convection Coefficient****Film Effectiveness Coefficient	TimeSpatial variablesTime, spatial variables	fluid_temperatureheat_flow_ratemass_flow_ratenxnynzpressureradiusrotational_speedtemperaturetemperature_differencethermal_capacitancethicknesstimevolume_flow_ratexyz
Free Stream Temperature	Time

In expressions, you can also use all built-in functions that are listed in Mathematical functions in expressions and most built-in functions that are listed in Thermal-flow functions in expressions.

Where do I find it?

Application	Pre/Post
Command Finder	Film Cooling
Simulation Navigator	Right-click the Constraint Set container node→New Constraint→Film Cooling

Learn more

Inputs to expressions

Look up more details

Auto-generated expressions

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

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Film Cooling, Simcenter 3D 2021.1 Series

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