modelMembraneHeatTransfer
model for heat transfer through a membrane
Information
This heat transfer model calculates the locally resolved heat flow through a thin membrane using the thermal conductivity λMembrane and the membrane thickness δMembrane .
heatPorts_a[i].Q̇ = (λMembrane ⁄ δMembrane ) (AMembrane ⁄ n ) (heatPorts_a[i].T - TMembrane[i] )
Analogue for the second surface of the membrane:
heatPorts_b[i].Q̇ = (λMembrane ⁄ δMembrane ) (AMembrane ⁄ n ) (heatPorts_b[i].T - TMembrane[i] )
If the energy dynamics are set to "Steady State" the membrane will not stroe any heat:
0 = heatPorts_b[i].Q̇ + heatPorts_a[i].Q̇
Otherwise the mebrane temperature will change with time.
mMembrane[i] cp,Membrane dTMembrane[i] = heatPorts_a[i].Q̇ + heatPorts_b[i].Q̇
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | n | 2 | Segmentation of membrane |
| Integer | nParallel | number of parallel air ducts | |
| Modelica.Units.SI.Length | lengthMem | length of membrane in flow direction | |
| Modelica.Units.SI.Length | widthMem | width of membrane | |
| Modelica.Units.SI.Length | thicknessMem | thickness of membrane | |
| Modelica.Units.SI.ThermalConductivity | lambdaMem | thermal conductivity of membrane | |
| Modelica.Units.SI.Density | rhoMem | density of membrane | |
| Modelica.Units.SI.SpecificHeatCapacity | cpMem | mass weighted heat capacity of membrane | |
| Modelica.Units.SI.Mass | mMem | rhoMem*(lengthMem*widthMem*thicknessMem)*nParallel | mass of membrane |
| Modelica.Units.SI.Area | areaMem | lengthMem*widthMem*nParallel | surface area of membrane |
| Modelica.Fluid.Types.Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamics.DynamicFreeInitial | Type of energy balance: dynamic (3 initialization options) or steady state |
| Modelica.Units.SI.Temperature | T_start | membrane temperature start value | |
| Modelica.Units.SI.TemperatureDifference | dT_start | start value for temperature difference between heatPorts_a and heatPorst_b |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Real | coeCroCous | coefficient for heat transfer reduction due to cross-flow portion | |
| Modelica.Units.SI.Mass | m | fill(mMem/n, n) | Distribution of wall mass |
| Modelica.Units.SI.Temperature | Tb | Temperature at side b | |
| Modelica.Units.SI.Temperature | Ta | Temperature at side a | |
| Modelica.Units.SI.Temperature | Ts | Membrane temperature | |
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heatPorts_a | Heat port to component boundary | |
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heatPorts_b | Heat port to component boundary |
Revisions
- August 21, 2018, by Martin Kremer:
First implementation.