modelPartialDuctHeatTransfer
Extends from PartialFlowHeatTransfer (base class for any flow heat transfer correlation).
Information
This model calculates the convective heat transfer coefficient α using the nusselt number correlation for rectangular air ducts by Muzychka and Yovanovich [1] (see function NusseltNumberMuzychka).
The air density, dynamic viscosity, thermal conductivity and Prandtl number are calculated as state variables. The Reynolds number is calculated using the density, dynmaic viscosity, flow velocity and the duct's cross section as characteristic length. The cross section is calculated using the duct's height and width.
The convective heat transfer coefficient is calculated as follows.
α = (Nu λ ) ⁄ √Across-section
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 nusslet 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. | |
| Internal Interface | |||
| Integer | n (from PartialHeatTransfer) | 1 | Number of heat transfer segments in x-Direction |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heatPorts (from PartialHeatTransfer) | Heat port to component boundary |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Medium.ThermodynamicState | states (from PartialHeatTransfer) | Thermodynamic states of flow segments | |
| Modelica.Units.SI.Area | surfaceAreas (from PartialHeatTransfer) | Heat transfer areas | |
| Modelica.Units.SI.HeatFlowRate | Q_flows (from PartialHeatTransfer) | Heat flow rates | |
| Modelica.Units.SI.Temperature | Ts (from PartialHeatTransfer) | Medium.temperature(states) | Temperature at states |
| Modelica.Units.SI.Velocity | vs (from PartialFlowHeatTransfer) | Mean velocities of fluid flow in segments | |
| Modelica.Units.SI.Length | lengths (from PartialFlowHeatTransfer) | Lengths along flow path | |
| Real | aspRats | aspect ratio between duct height and width | |
| Modelica.Units.SI.CoefficientOfHeatTransfer | hCons | ||
| 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 | Prs | Prandtl number | |
| Real | Res | Reynolds number | |
| Real | Nus | Nusselt number | |
| Modelica.Units.SI.Area | croSecs | cross section of duct | |
| Real | zSterns | dimensionless length |
Revisions
- August 21, 2018, by Martin Kremer:
First implementation.