Dittus–Boelter Convection

Nusselt number (and film coefficient h) for turbulent pipe flow: Nu = 0.023·Re^0.8·Pr^n (n = 0.4 heating, 0.3 cooling).

Heat transferConvection

Reynolds number - Prandtl number - Fluid thermal conductivityW/(m·K)Hydraulic diametermmHeating or cooling

Nusselt number: 201.7 -

Film coefficient h: 6,252W/(m²·K)

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Formula, assumptions, and limits

Nu = 0.023 \cdot Re^{0.8} \cdot Pr^n, \quad h = \frac{Nu \cdot k}{D_h}

Symbol	Meaning	Unit
$Re$	Reynolds number
$Pr$	Prandtl number = ν/α
$k$	Thermal conductivity	W/(m·K)
$D_h$	Hydraulic diameter	m
$h$	Convective film coefficient	W/(m²·K)

Source: Dittus-Boelter (1930)

In short

Nusselt number (and film coefficient h) for turbulent pipe flow: Nu = 0.

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