Convection correlations: laminar flow in circular tubes ·2. The entry region for the constant surface temperature condition D 0.0668RepP D Nun=3.66+ 2/3 1+0.04 Ren pr thermal entry length -Thermal e Combined entry lensth Constant surface Pr=0.7) heat flua Entrance terion Fuly developed region 10 4.36 Constant srface temperature 0001 0005001 0050.1 0.5 G Heat Transfer Su Yongkang School of Mechanical EngineeringHeat Transfer Su Yongkang School of Mechanical Engineering # 5 Convection correlations: laminar flow in circular tubes • 2. The entry region for the constant surface temperature condition thermal entry length 2/3 Re Pr L D 1 0.04 Re Pr L D 0.0668 3.66             +       = + D D NuD