大型水泵出水流道优化水力设计

研究大型水泵出水流道扩散角、断面形状和中心线走向对水力损失的影响，提出当量扩散角概念，以包括沿程摩阻水力损失、扩散水力损失和出口水力损失在内的总水力损失最小为目标，对出水流道扩散角和断面形状进行优化，提出流道中心线走向优化的原则。研究结果表明，在进、出口断面位置一定的情况下，出水流道存在最优扩散角，使总水力损失最小。试验证明，由于水泵出水弯管的作用，出水流道实际开始脱流的扩散角小于理论计算的最优扩散角；采用优化渐变扩散角，可使水力损失进一步减小；矩形流道断面以正方形为最优，且存在最优角圆，使单位长流道沿程水力损失最小。成果对减小出水流道水力损失，实现泵装置优化设计，提高泵装置效率有重大意义。

OPTIMUM HYDRAULIC DESIGN FOR DISCHARGE PASSAGE OF LARGE PUMP

The influences of angle of flare,section figure and centerline of strike of discharge passage of a large pump on its hydraulic loss are studied.The concept of equivalent angle of flare is advanced.For the purpose of minimizing discharge pas- sage total hydraulic loss,which includes frictional hydraulic loss,diffuse hydraulic loss and exit hydraulic loss,the angle of flare and section figure of the passage are optimized,the opti- mizing principles of the passage centerline of strike are put forward.The research results indicate that the passage has the optimum angle of flare which makes its hydraulic loss the least for certain positions of inlet section and exit section.Tests prove that the actual angle of flare from which separation fluids just occur is smaller than the optimum angle of flare obtained by theoretical calculation because of the influences of discharge curved pipe.The gradual changing optimum angle of flare could make the hydraulic loss even smaller than the constant optimum angle of flare.The optimum passage section figure of rectangle is square,and the rectangle has 4 optimum comer circular arcs which make the hydraulic loss of friction loss of per unit length passage the least.The results are significant for decreasing hy- draulic loss of discharge passage,pump assembly optimum design and increasing pump assembly efficiency.