热量传输 ReOd0.05×0.02 =1105<2300层流 9.05×10 Gpgd3△t321×104×981×0023×(55-25) 922760 905×10-7)2 Nm=05RePn(GPy(P、、 L/d=1.5/0.02=75>50 N 0.15×1105032×6.22033×(922760×622)1×(6.23.26)025=14.37 0.6085 u 14.37× 4372w/m2°C 0.02 出 (#‹#› 第二章 热 量 传 输 1105 2300 9.05 10 d 0.05 0.02 Re 7 f f =    =   = − 层流 922760 (9.05 10 ) gd t 3.21 10 9.81 0.02 (55 25) G 7 2 4 3 2 3 rf =      − =    = − − l 0.2 5 w 0.1 f f 0.3 3 rf 0.3 2 u f f ) Pr Pr N = 0.15Re p (Gr Pr) (  L/d=1.5/0.02=75>50 l  =1 Nuf =0.15×11050.32×6.220.33×(922760×6.22)0.1×(6.22/3.26)0.25=14.37 437.2w / m C 0.02 0.6085 14.37 d Nu 2 o f =  =   =