潜水磨碎泵磨碎装置的优化设计与试验

为了提高无堵塞磨碎泵的水力性能及改善磨碎效果,在分析影响无阻塞潜水磨碎泵水力性能和磨碎效果的主要几何因素的基础上建立无阻塞潜水磨碎泵的优化方案,结合无堵塞潜水磨碎泵的使用特点,通过数值模拟软件ANSYS-CFX对无阻塞潜水磨碎泵优化方案进行模拟计算及改进,并通过样机试验对CFD模拟结果进行试验验证,结果表明:磨碎泵动刀盘刀头数目是影响泵水力性能的最主要因素,在保证磨碎效果的前提下,应尽量选用较少的刀头数目;动静刀盘间隙对泵外特性的影响是仅次于动刀盘刀头数目,随着间隙的减小,磨碎泵的水力性能下降明显,但磨碎泵的无过载性能有所提升。经综合分析,GSP-22型磨碎泵动刀盘刀头数目为2和动静刀盘间隙为1.5 mm时最优,同时兼顾了磨碎泵的水力性能和磨碎效果,为磨碎泵的优化设计提供参考指导。

Optimal design and experiment of submerged grinder pump grinding device

Abstract: With the rapid development of industry and agriculture, more and more fiber and other impurities are doped in the sewage, but the ordinary sewage pump is easy to be blocked in operation and has been unable to meet the requirements of transport medium which contains high fiber impurities, so the sewage pump with auxiliary cutting grinding device (i.e., non-jamed submerged grinder pump) has been widely applied. How to ensure the grinding effect and high efficiency has become one of the hotspots in the research field of submerged grinder pump. This paper uses the software ANSYS-CFX to conduct steady and unsteady calculations for the non-jammed submerged grinder pump. Combined with the features of submerged grinder pump, the hydraulic design and the three-dimensional modeling are conducted for the main flow passage components of the grind pump, the structured hexahedral mesh and the grid-independent test for the model, and also numerical simulation and experimental verification are made for the external characteristics of non-jammed submerged grinder pump. The paper analyzes the most important factors which affect the external characteristics of non-jammed submerged grinder pump to search the optimization method of the grinder pump, and the results show that the installation of grinding device has great influence on hydraulic performance of the submerged pump, there is a decline in the grinding pump lift, the point of maximum efficiency shifts to the low flow rate condition, the pump efficiency is reduced, and the shaft power consumption increases about by 40% compared with that without grinding device. Through the study of submerged grinder pump model with 3 different radial clearances of dynamic and static cutter which are 1, 1.5 and 2 mm, it is found that the better grinding effect goes along with the smaller cutter radial clearance, and with the decrease of the dynamic and static cutter's radial clearance, the submerged grinder pump lift drops and especially under the large flow condition, the shaft power increases, the highest efficiency values decline and the high efficiency area is narrowed, but no overload performance of the submerged grinder pump improves. Through the study of submerged grinder pump model with 3 different cutter head numbers which are 2, 3 and 4, it is found that the cutter head number has greater effect on the hydraulic performance of the submerged grinder pump compared with the dynamic and static cutter's radial clearance; the increase of cutter head number and crowding coefficient at the pump inlet will increase the hydraulic loss, and coupled with cavitation intensified at the cutter heads of the grinding device, the loss at the grinding device increases significantly, resulting in the drop of pump lift, the overall efficiency decline and the overall shaft power increase, so under the premise of guaranteeing cutting grinding effect, it should try to use less cutter head number as far as possibly, and the optimum number is 2. Through comprehensive analysis, the optimal design of GSP-22-type non-jammed submerged grinder pump is that its dynamic and static cutter's radial clearance is 1.5 mm and its dynamic cutter head number is 2, which takes the ground pump hydraulic performance and grinding effect into account, and provides theoretical guidance for the optimal design of submerged grinder pump.