钢管糙率 n=0.012
管道摩阻 S=10.3*n^2/d^5.33 =10.3*0.012^2/0.7^5.33 =0.00993
流量Q=[0.4*1000000/(1000*9.8*0.0093*1000)]^(1/2)=2.095 m^3/s = 7542 m^3/h
流速 V= 4Q/（3.1416d^2)=4*2.095/（3.1416*0.7^2) = 5.44 m/s
每小时流量7542立方立方米,流速5.44米米秒