921通道内无相变的对流换热 ■直管,层流(Re<230) 0.0668D/L Re p N=3658+ 2/3 1+0.04D/L Re p ■直管和盘管,紊流(Re>3000 n=0023Re02 1+35D,/D9.2.1 通道内无相变的对流换热 „ 直管，层流 „ 直管和盘管，紊流 ( ) Re < 2300 ( ) [ ] ( ) N DL P DL P u e r e r = + + 3 658 0 0668 1 0 04 2 3 . . / Re . / Re / ( ) Re > 3000 j D H e = + [ ] ( ) Dh − 0 023 1 35 0 2 . Re . /