.TRANSFORM.HeatAndMassTransfer.ClosureRelations.HeatTransfer.Functions.SinglePhase.InternalFlow.Nu_Overall_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 ≤ 1e6, 0.1 ≤ Pr ≤ 1000, d/L ≤ 1
• Applies only to circular pipes in the laminar region but can approximate other with the characteristic dimension. Turbulent region is independent of pipe shape.

References

1. VDI Heat Atlas 2E, 2010.
2. Heat Transfer. Nellis and Klein. 2009

Interface

function Nu_Overall_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 SI.Height roughness = 2.5e-5 "Average height of surface asperities";
  input Boolean constantTwall = true "= true for constant wall temperature correlation else constant heat flux (laminar conditions only Re ~< 2300)";
  output SI.NusseltNumber Nu "Nusselt number";
end Nu_Overall_Local_Developed_Circular;