modelCrossFlowReduction
model that calculates reduction factor for mass 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 mass transfer coeeficient ktot, the surface area A and the minimum mass flow rate ṁ.
NTU = (ktot A) ⁄ ṁmin
Using the number of transfer units and the cross-flow portion of the whole transfer area the coeefficient for the mass 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.Area | surfaceAreas | Heat transfer areas | |
| Real | aspRatCroToTot | ratio of cross flow of air duct | |
| Real | C_conv | 3.35*10^(-16) | conversion factor for permeance to calculate SI-units from Barrer |
| Modelica.Units.SI.MolarMass | M_steam | 0.01802 |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Real | k_tots | total mass transfer coefficient | |
| Real | NTUs | number of heat transfer units | |
| Modelica.Blocks.Interfaces.RealInput | perMem | membrane permeability in Barrer | |
| Real | kCons1 | convective mass transfer coefficients of air flow 1 | |
| Real | kCons2 | convective mass 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 | |
| Modelica.Blocks.Interfaces.RealOutput | coeCroCous | coefficient for heat transfer reduction due to cross-flow portion |
Revisions
- August 21, 2018, by Martin Kremer:
First implementation.