The Mechanical Engineering Handbook



Nusselt Number

Nusselt Number Equation



$$ Nu = \frac{hL}{k} $$ where:

Nu   =   Nusselt Numebr   (Dimensionless)

h   =   Heat Transfer Coefficient  (W/m²K)

L   =   Characteristic Length   (m)

k   =   Thermal Conductivity   (W/mK)


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Equation Assumptions



Assumptions:

  • The fluid is incompressible.
  • Heat transfer by radiation is neglected.
  • Steady flow conditions.
  • No heat is generated.