Convection correlations:laminar flow in circular tubes 1.The fully developed region from the energy equation,we can obtain the exact solution. for constant surface heat flux hD Nup= =4.36 q"=C k for constant surface temperature hD Nup= k =3.66 T、=C Note:the thermal conductivity k should be evaluated at T Heat Transfer #4 Su Yongkang School of Mechanical EngineeringHeat Transfer Su Yongkang School of Mechanical Engineering # 4 Convection correlations: laminar flow in circular tubes • 1. The fully developed region from the energy equation,we can obtain the exact solution. for constant surface heat flux for constant surface temperature Note: the thermal conductivity k should be evaluated at .   4.36 k hD NuD q  s   C   3.66 k hD NuD Ts  C Tm