modelLocalPipeFlowHeatTransfer
LocalPipeFlowHeatTransfer: Laminar and turbulent forced convection in pipes, local coefficients
Extends from PartialPipeFlowHeatTransfer (Base class for pipe heat transfer correlation in terms of Nusselt number heat transfer in a circular pipe for laminar and turbulent one-phase flow).
Information
Heat transfer model for laminar and turbulent flow in pipes. Range of validity:
- fully developed pipe flow
- forced convection
- one phase Newtonian fluid
- (spatial) constant wall temperature in the laminar region
- 0 ≤ Re ≤ 1e6, 0.6 ≤ Pr ≤ 100, d/L ≤ 1
- The correlation holds for non-circular pipes only in the turbulent region. Use diameter=4*crossArea/perimeter as characteristic length.
The correlation takes into account the spatial position along the pipe flow, which changes discontinuously at flow reversal. However, the heat transfer coefficient itself is continuous around zero flow rate, but not its derivative.
References
- Verein Deutscher Ingenieure (1997):
- VDI Wärmeatlas. Springer Verlag, Ed. 8, 1997.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.CoefficientOfHeatTransfer | alpha0 (from PartialPipeFlowHeatTransfer) | 100 | Guess value for heat transfer coefficients |
| Internal Interface | |||
| Integer | n (from PartialHeatTransfer) | 1 | Number of heat transfer segments |
| Boolean | use_k (from PartialHeatTransfer) | false | = true to use k value for thermal isolation |
| Ambient | |||
| SI.CoefficientOfHeatTransfer | k (from PartialHeatTransfer) | 0 | Heat transfer coefficient to ambient |
| SI.Temperature | T_ambient (from PartialHeatTransfer) | system.T_ambient | Ambient temperature |
| Internal interface › Geometry | |||
| Real | nParallel (from PartialFlowHeatTransfer) | Number of identical parallel flow devices | |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.HeatPorts_a | heatPorts (from PartialHeatTransfer) | Heat port to component boundary |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Medium.ThermodynamicState | states (from PartialHeatTransfer) | Thermodynamic states of flow segments | |
| SI.Area | surfaceAreas (from PartialHeatTransfer) | Heat transfer areas | |
| SI.HeatFlowRate | Q_flows (from PartialHeatTransfer) | Heat flow rates | |
| Modelica.Fluid.System | system (from PartialHeatTransfer) | System wide properties | |
| Medium.Temperature | Ts (from PartialHeatTransfer) | Medium.temperature(states) | Temperatures defined by fluid states |
| SI.Velocity | vs (from PartialFlowHeatTransfer) | Mean velocities of fluid flow in segments | |
| SI.Length | lengths (from PartialFlowHeatTransfer) | Lengths along flow path | |
| SI.Length | dimensions (from PartialFlowHeatTransfer) | Characteristic dimensions for fluid flow (diameter for pipe flow) | |
| Modelica.Fluid.Types.Roughness | roughnesses (from PartialFlowHeatTransfer) | Average heights of surface asperities | |
| SI.CoefficientOfHeatTransfer | alphas (from PartialPipeFlowHeatTransfer) | Heat transfer coefficient | |
| Real | Res (from PartialPipeFlowHeatTransfer) | Reynolds numbers | |
| Real | Prs (from PartialPipeFlowHeatTransfer) | Prandtl numbers | |
| Real | Nus (from PartialPipeFlowHeatTransfer) | Nusselt numbers | |
| Medium.Density | ds (from PartialPipeFlowHeatTransfer) | Densities | |
| Medium.DynamicViscosity | mus (from PartialPipeFlowHeatTransfer) | Dynamic viscosities | |
| Medium.ThermalConductivity | lambdas (from PartialPipeFlowHeatTransfer) | Thermal conductivity | |
| SI.Length | diameters (from PartialPipeFlowHeatTransfer) | dimensions | Hydraulic diameters for pipe flow |