Convection correlations:laminar flow in circular tubes 0 2.The entry region for the constant surface temperature condition Rep Pr Wup=3.66+ 72/3 人1 1+-0.04Rep Pr thermal entry length ----Thermal entry length Combined entry length Constant sorface (Prs0.7) heat flux 20 Entrance region Fulty developed region 10 4.36 Constant surface 3.66 temperature 2 0.001 0.c050.01 0.0501 0.5 Heat Transfer #5 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