# Nusselt number for a developing turbulent flow in the entrance region

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1. Apr 28, 2017

Anyone knows if i can calculated Nusselt number for a developing turbulent flow in the entrance region for a duct/ tube?

2. Apr 29, 2017

### Nidum

Not my specialist field but I tried putting literally ' Nusselt number for a developing turbulent flow in the entrance region for a duct ' into Google and obtained some useful and relevant information .

Have you even tried this ?

Last edited: Apr 29, 2017
3. May 1, 2017

### Mech_Engineer

The Nusselt number is the ratio of convective to conductive heat transfer in a flow. It's fundamentally defined as:
$$Nu=\frac{h*L}{k}$$
The Nusselt number depends on the convection flow's parameters, sometimes summarized in the convective coefficient "h". Your options are to calculate the convective coefficient for your application, or sometimes correlations are developed which use the flow parameters (such as Rayleigh number, forced vs. free convection, geometry aspects, etc.)

Wikipedia lists a couple of emprically-derived equations under the topic of Nusselt number for pipe flow, take a look here: Wikipedia: Nusselt Number- Forced Convection in Turbulent Pipe Flow