Convection

Convective heat transfer with the input conductance Gc.

  • signal
  • thermal
  • Modelica Standard Library
  • 3 ports
BlockConvectionKindconvectionLibraryThermal

Description

Convective heat transfer between a solid surface and a fluid, with the conductance given by an input signal. Use it when the heat transfer coefficient depends on flow speed or another computed quantity.

Example

Cooling a hot part A 10 W part cools through a thermal resistance into a heatsink that convects and radiates to 20 °C.

10 WPart 100 J/KHeat flowR 2 K/WHeatsink 500 J/Kh·A 5 W/KConvectionAir 20 °CRadiationRoom 20 °CPart temperatureAcross R350 KHeld at 350 KG 1 W/KBody 100 J/K20 W at 1500 sHeaterBody temperature
In Gradara, select a Convection block and press F1, then choose Open example. It opens as a new model in My models, ready to run.

Also in this example:ConstantStepHeat capacitorThermal conductorThermal resistorRadiationFixed temperatureTemperature sourceFixed heat flowHeat flow sourceTemperature sensorHeat flow sensorTemperature difference sensor

Ports

Inputs 1

  • Gcsignal · W/K

    Convective conductance h · A, in W/K.

Conserving terminals 2

  • solidthermal

    Heat port at the solid surface. Heat flow Q from solid to fluid enters here.

  • fluidthermal

    Heat port at the fluid. Q leaves here.

Equations

Modelica
ΔT = solid.T − fluid.T
Q = Gc · ΔT
solid.Q_flow = Q, fluid.Q_flow = −Q

Implementation

Modelica Standard Library 4.1.0Modelica.Thermal.HeatTransfer.Components.Convection
MSL documentation

Assumptions and limitations

  • No heat storage in the boundary layer. The fluid is a single temperature.

Tips

  • For a constant coefficient, feed Gc from a Constant block.

See also

Select a block in Gradara and press F1 to open its page offline.