Hydraulic Optimization Of Single Stage Double Suction Split Centrifugal Pumps And Study On Sediment Wear

There has being an increasing demand on pumps for engineerings such ashydropower, agricultural irrigation and construction work resent years along with thereapidly development of national economy. The double suction split pumps, with largeflow, high head and excellent cavitation performance, are one sort of the most widely usedwater supply pumps. There is still a wide gap between domestic split pumps, althoughwhich were designed and produced earlier, and foreign ones in design technology, as wellas numerous deficiencies in term of energy and cavitation performance and stability inhydraulic models. Impellers wear seriously and deteriorate drasticly in the transpotion ofmedium contains large amounts of sediment.The OS series double suction split pumps is a set pump hydraulic models in domesticwhich is relatively mature, but the geometry and structure of suction chambers haverestricted the improvement of their cavitation performance to some extent. Therefore, theyhave been reformed in this dissertation through numerical simulations and experement,based on their basic theory, with not only the advantage of original structure retained, butalso new ground broken, and the convenience for manufacturing taken into account.Impellers are the working part that affects the hydraulic performance of pumps mostsignificantly. Traditional researches concentrate on low specific speed centrifugalimpellers, but we are dedicated to the study of high ones in this dissertation. We use highlycurved entrance edges to improve the cavitation performance of impellers, which lead toan effective method to reduce the NPSHrunder the premise that do not affects theirefficiency. We have also studied the impact of different parameters of impellers on itsenergy characteristics. The hydraulic characteristics of original models have been adjustedand the performance of newly developed ones is more in line with the requirements of theindustry.We have also studied the wear on blades due to tiny sediment particles in thisdissertation. With the Lagrangian Tracking Implementation, trajectories of the sedimentparticles inside the impellers and the wear intensity distribution on the balde surfaces havebeen simulated. The simulation results, which show good agreement with the experimentsin the references when compared, are correct and credible. The guide vanes on the sealingbody upstream of the impeller could inhibit the wear and tear to baldes, and could evenreduce it on the pressure faces significantly with the blade flow lines designed rationally.In order to reduce the sediment induced wear on the suction faces at the end of blades, thethickness of the blades is disposed, and the impact angles between sediment trajectories and blade surfaces are reduced. The result shows good effect.The optimum design method presented in this dissertation have been applied to thedevelopment of multiple sets of high-efficiency and anti-cavitation pump hydraulicmodels, all of which have been already mass producted and applied to a number ofpractical engineering successfully. At the same time, some of them have even beenexported to developed countries, being well received by the company and users. However,the actual effect of the wear resistant impellers needs long-term observations in practicaloperation.