Convective heat transfer coefficient with Nusselt number for Internal/turbulent flow
Although convective heat transfer can be derived analytically through dimensional analysis, exact analysis of the boundary layer, approximate integral analysis of the boundary layer and analogies between energy and momentum transfer, these analytic approaches may not offer practical solutions to all problems when there are no mathematical models applicable.
For a forced convection in Internal flow, turbulent flow:
The Dittus-Bölter correlation (1930) is a common and particularly simple correlation useful for many applications. This correlation is applicable when forced convection is the only mode of heat transfer; i.e., there is no boiling, condensation, significant radiation, etc. The accuracy of this correlation is anticipated to be ±15%.
For a fluid flowing in a straight circular pipe with a Reynolds number between 10,000 and 120,000 (in the turbulent pipe flow range), when the fluid’s Prandtl number is between 0.7 and 120, for a location far from the pipe entrance (more than 10 pipe diameters; more than 50 diameters according to many authors) or other flow disturbances, and when the pipe surface is hydraulically smooth, the heat transfer coefficient (or Thermal exchange coefficient) between the bulk of the fluid and the pipe surface can be expressed explicitly as shown here.Related formulas
|h||Convective heat transfer coefficient (W/m2*K1)|
|kW||Thermal conductivity at specified temperature T (W/m*K)|
|DH||Hydraulic diameter (m)|
|Nu||Nusselt number (dimensionless)|