LocalPipeFlowHeatTransfer

LocalPipeFlowHeatTransfer: Laminar and turbulent forced convection in pipes, local coefficients

Information

This information is part of the Modelica Standard Library maintained by the Modelica Association.

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 (6)

n	Value: 1 Type: Integer Description: Number of heat transfer segments
use_k	Value: false Type: Boolean Description: = true to use k value for thermal isolation
k	Value: 0 Type: CoefficientOfHeatTransfer (W/(m²·K)) Description: Heat transfer coefficient to ambient
T_ambient	Value: system.T_ambient Type: Temperature (K) Description: Ambient temperature
nParallel	Value: Type: Real Description: number of identical parallel flow devices
alpha0	Value: 100 Type: CoefficientOfHeatTransfer (W/(m²·K)) Description: guess value for heat transfer coefficients

Inputs (6)

states	Type: ThermodynamicState[n] Description: Thermodynamic states of flow segments
surfaceAreas	Type: Area[n] (m²) Description: Heat transfer areas
vs	Type: Velocity[n] (m/s) Description: Mean velocities of fluid flow in segments
lengths	Type: Length[n] (m) Description: Lengths along flow path
dimensions	Type: Length[n] (m) Description: Characteristic dimensions for fluid flow (diameter for pipe flow)
roughnesses	Type: Roughness[n] (m) Description: Average heights of surface asperities