modelPartialDuctMassTransfer
Extends from PartialFlowMassTransfer.
Information
This model calculates the convective mass transfer coefficient β using the nusselt number correlation for rectangular air ducts by Muzychka and Yovanovich [1] and the analogy between heat and mass transfer (see function SherwoodNumberMuzychka).
Sh = Nu , Sc = Pr
The air density, dynamic viscosity and thermal conductivity are calculated as state variables. The Schmidt number is calculated using the dynamic viscosity, density and the diffusion coefficient of water vapour into air. The Reynolds number is calculated using the density, dynamic viscosity, flow velocity and the duct's cross section as characteristic length. The cross section is calculated using the duct's height and width.
Sc = μ ⁄ (ρ D )
The convective heat transfer coefficient is calculated as follows.
β = (Sh ρ D ) ⁄ √Across-section
The diffusion coefficient of water vapour into air D is calculated using the function DiffusionCoefficient.
References
[1]: Muzychka, Y. S.; Yovanovich, M. M. : Laminar Forced Convection Heat Transfer in the Combined Entry Region of Non-Circular Ducts ; Transactions of the ASME; Vol. 126; February 2004
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | nWidth | number of parallel segments in width direction | |
| Modelica.Units.SI.Length | heights | height of duct | |
| Modelica.Units.SI.Length | widths | width of duct | |
| Boolean | uniWalTem | true if uniform wall temperature boundary conditions | |
| Boolean | local | true if local Sherwood number or false if average shall be calculated | |
| Boolean | recDuct | true if rectangular duct is used for Sherwood number calculation, else flat gap is used. |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Real | aspRats | aspect ratio between duct height and width | |
| Real | kCons | ||
| Modelica.Units.SI.ThermalConductivity | lambdas | thermal conductivity of medium | |
| Modelica.Units.SI.Density | rhos | density of medium | |
| Modelica.Units.SI.DynamicViscosity | mus | dynamic viscosity of medium | |
| Real | Scs | Schmidt number | |
| Real | Res | Reynolds number | |
| Real | Shs | Shwerwood number | |
| Modelica.Units.SI.Area | croSecs | cross section of duct | |
| Real | zSterns | dimensionless length |
Revisions
- August 21, 2018, by Martin Kremer:
First implementation.