Convection correlations:laminar flow in circular tubes .2.The entry region(cont'd) for the combined entry length 0.14 ·For values of [RepPr/(L/DΨ(u/u,P4}≥2 T.=C 0.48≤Pr<16,700 0.0044<(u14,)<9.75 All fluid properties evaluated at the mean T Tm =(Tmi+Tm.o)/2 Heat Transfer #6 Su Yongkang School of Mechanical EngineeringHeat Transfer Su Yongkang School of Mechanical Engineering # 6 Convection correlations: laminar flow in circular tubes • 2. The entry region(cont’d) for the combined entry length • For values of 1/3 0.14 / Re Pr 1.86              s D D L D Nu   Re Pr/( / )  /   2 1/3 0.14 D L D  s  All fluid properties evaluated at the mean T  / 2 Tm  Tm,i Tm,o Ts  C 0.48  Pr 16,700 0.0044   /   9.75  s