modelCrossFlowReduction
model that calculates reduction factor for heat transfer in quasi-counter flow arrangement
Information
This model calculates a reduction factor for a cross-counter-flow arrangement. The calculation is based on the Efficiency-NTU-Method.
The number of transfer units NTU is calculated with the total heat transfer coeeficient htot, the surface area A and the minimum heat capacity flow consiting of the mass flow rate ṁ and the specific heat capacitiy cp.
NTU = (htot A) ⁄ (ṁ cp)min
Using the number of transfer units and the cross-flow portion of the whole transfer area the coeefficient for the heat transfer reduction is calculated.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | n | 1 | number of discrete elements in flow direction |
| Integer | nParallel | 1 | number of parallel membranes |
| Modelica.Units.SI.Length | thicknessMem | thickness of membranes | |
| Modelica.Units.SI.ThermalConductivity | lambdaMem | thermal conductivity of membrane | |
| Modelica.Units.SI.Area | surfaceAreas | Heat transfer areas | |
| Real | aspRatCroToTot | cross flow portion of transfer area |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealOutput | coeCroCous | coefficient for heat transfer reduction due to cross-flow portion |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Real | h_tots | total heat transfer coefficient | |
| Real | NTUs | number of heat transfer units | |
| Modelica.Units.SI.HeatCapacity | cp1 | heat capacity of air flow 1 | |
| Modelica.Units.SI.HeatCapacity | cp2 | heat capacity of air flow 2 | |
| Modelica.Units.SI.CoefficientOfHeatTransfer | hCons1 | convective heat transfer coefficients of air flow 1 | |
| Modelica.Units.SI.CoefficientOfHeatTransfer | hCons2 | convective heat transfer coefficients of air flow 2 | |
| Modelica.Units.SI.MassFlowRate | m_flow1 | mass flow rate of air flow 1 | |
| Modelica.Units.SI.MassFlowRate | m_flow2 | mass flow rate of air flow 2 |
Revisions
- August 21, 2018, by Martin Kremer:
First implementation.