管道动压Pd=ρV2/2=1.2*13^2/2= 101.4 Pa沿程阻力系数 λ=1.15*0.0134/d^0.284=1.15*0.0134/0.3^0.284=0.022沿程压力损失 Py=(λL/d)Pd=(0.022*21/0.3)*101.4= 156.2 Pa三通局部阻力系数ζ=0.2,弯头阻力系数ζ=0.17....