解:管道中油液的流速,选取ⅴ=3m/s,代入式(5-5)得 40×10 d=1.3,9=13 16.8mm≈17mm 60×3 油管的壁厚按下式计算 6.3×106×17×8 0.71mn 2×600×10解：管道中油液的流速，选取 v＝3m/s,代入式（5-5）得 mm mm v q 16.8 17 60 3 40 10 1.3 1.3 3 = ≈ × × = = − d 油管的壁厚按下式计算 mm pdn b 0.71 2 600 10 6.3 10 17 8 2 6 6 × × × × × = = σ δ