.TRANSFORM.HeatAndMassTransfer.ClosureRelations.HeatTransfer.Functions.SinglePhase.InternalFlow.Nu_Laminar_Local_Developed_Circular

Information

Local heat transfer model for fully developed laminar and turbulent flow in circular pipes.

• The laminar region has been shown to be significantly impacted by the duct shape and wall boundary conditions but not the surface roughness.
• The turbulent region has been shown to be highly depenedent of surface roughness but not impacted by duct shape or wall boundary conditions.
• The characteristic dimension is defined as dimension = 4*crossArea/perimeter where "crossArea" is the cross sectional flow area and "perimeter" is the wetted perimeter.

Range of validity:

• fully developed pipe flow
• forced convection
• one phase Newtonian fluid
• constant wall temperature or constant heat flux in laminar region
• 0 ≤ Re ≤ ~2300, 0.1 ≤ Pr ≤ 1000, d/L ≤ 1
• Applies only to circular pipes in the laminar region but can approximate other shapes with the characteristic dimension.
• Laminar region is independent of surface roughness

References

1. VDI Heat Atlas 2E, 2010.

Interface

function Nu_Laminar_Local_Developed_Circular
  input SI.ReynoldsNumber Re "Reynolds Number";
  input SI.PrandtlNumber Pr "Prandtl Number";
  input SI.Length x "Position of local heat transfer calculation";
  input SI.Length dimension "Characteristic dimension (e.g., hydraulic diameter)";
  input Boolean constantTwall = true "= true for constant wall temperature correlation else constant heat flux";
  output SI.NusseltNumber Nu "Nusselt number";
end Nu_Laminar_Local_Developed_Circular;