水头损失计算已知条件：压力0.2Mpa,管径DN50,镀锌钢管,水平距离4000米,不计阀门弯头等.求流量、流速、水头损

水头损失 H = P/（pg)=0.2*10^6/(1000*9.8) = 20.41 m
管道比阻 S=10.3n^2/d^5.33 = 10.38*0.012^2/0.05^5.33 = 12755.27
管道流量 Q=[h/(SL)]=[20.41/(12755.27*4000)]=6.325*10^(-4) m^3/s
= 0.6325 L/S
流速 V=4Q/(3.14*d^2)=4*6.325*10^(-4)/(3.14*0.05^2)=0.3223 m/s