水煤浆流经小曲率半径弯管的阻力特性研究

A Study of Resistance Characteristics of Coal-water Slurry Passing Through a Tube Bend with a Small Curvature Radius

在自制试验台上研究了水煤浆流经小曲率半径90°水平弯管的局部阻力特性,分析了不同的曲率半径Rc对弯管的局部压力损失、压力损失系数以及摩擦阻力损失之比的影响。结果表明:随着雷诺数Re的增加,弯管的局部压力损失增大,而压力损失系数先降低后增加。考虑到曲率半径较小,弯管的局部压力损失由不规则流动损失与弯管轴线加长所产生的沿程阻力决定。弯管曲率半径越大,临界雷诺数就越大。弯管摩擦阻力损失之比随着Dean数的增加先降后升。Rc/R为4.0的弯管的局部压力损失、压力损失系数以及摩擦阻力损失之比均最小。

On a self-made test stand,studied were the local resistance characteristics of water-coal slurry passing through a 90° horizontal tube bend with a small curvature radius along with an analysis of the influence of various curvature radii Rc on the local pressure loss,pressure loss coefficient and friction resistance loss ratio of the bend. The results of the study show that with an increase of Reynolds Number Re,the local pressure loss of the bend will increase,but the pressure loss coefficient will first decrease and then increase. In view of the curvature radii being relatively small,the local pressure loss of the bend will be determined by the irregular flow loss and the path resistance produced by the lengthened axial line of the bend. The greater the curvature radius of the bend,the greater the critical Reynolds Number. The friction resistance loss ratio of the bend will first go down and then up with an increase of Dean Number. When the Rc/R of the bend equals 4,its local pressure loss,pressure loss coefficient and friction resistance loss ratio will all attain a minimum value.