Fixed heat flow

Injects a constant heat flow into its port.

  • thermal
  • Modelica Standard Library
  • 1 port
  • 1 parameter
BlockFixed heat flowKindfixedHeatFlowLibraryThermal

Description

Injects a constant heat flow into whatever its port is connected to, whatever the port temperature. Use it for a steady power dissipation such as a component’s losses.

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 Fixed heat flow 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 resistorConvectionRadiationFixed temperatureTemperature sourceHeat flow sourceTemperature sensorHeat flow sensorTemperature difference sensor

Ports

Conserving terminals 1

  • Qportthermal

    Heat port. The block delivers Q_flow out of this port into the connected network.

Parameters

  • Heat flowQ_flow10 W

    Heat flow, in watts. Positive heats the connected network; negative cools it.

Equations

Modelica
port.Q_flow = −Q_flow

Implementation

Modelica Standard Library 4.1.0Modelica.Thermal.HeatTransfer.Sources.FixedHeatFlow
MSL documentation

Assumptions and limitations

  • A network fed only by heat-flow sources, with no heat capacity or fixed temperature, has no defined temperature.

See also

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