Characteristic Research Of Slit-laden Water Of Internal Flow In Centrifugal Pump

There are many large engineering of the Yellow River, which play an important role to the development of farming and animal husbandry, whose irrigation area is broad. Double suction centrifugal pump are widely used in the projects of Yellow River, which with high flow, high lift, stable performance, etc. Because of the Yellow River sediment concentration is big, causing the severe abrasion of the centrifugal pump flow components damaged, the centrifugal pump out of the water flow loosed, the head and efficiency declined, the energy consumption high, which seriously affect the safe and stable operation of the centrifugal pump. The main damage parts for the Yellow River is pump impeller, the main damage of the impeller blade was the individual leaf middle position, import, export and the destroy form was scratch, blade thickness thinning and pits of blade material appeared off the pump lift serious moment come to perforation, which reduce the efficiency or appear the phenomenon such as vibration, and it is which destruction maintenance workload is big, resource consumption is high, seriously hindered the irrigation operation.This topic is based on computational fluid dynamics, which is by Fluent software numerical simulation for one of the large double suction centrifugal pump of internal flow. Pro/E software was used to establish geometric model of internal flow of centrifugal pump, the1CEM software model was used to meshing, the Fluent software was provided by the SIMPLEC algorithm and the standard k-ε epsilon turbulence equations was used for numerical simulation of internal flow centrifugal pump. Which are simulated respectively, containing sand grains of sand particle size and different volume fraction, particle size and the same volume fraction in five different conditions such as internal flow of centrifugal pump impeller solid liquid two phase turbulent flow field. According to the five different condition simulation calculated, the velocity field and pressure field distribution, analyzed the flow characteristics inside the impeller, working medium effected on the performance of the pump, and slip factor variation law and wear mechanism of blade which were discussed, and get the following main conclusions:(1) The slit-laden water slip factor decreases with the increasing of traffic. Sandy water volume fraction is the main factors which influencing the slip factor, sliding coefficient decreases with the increase of volume fraction; Though the influence of slip factor on particle size is small, the sliding coefficient is also slowly decreasing.(2) The blade inlet of damage is mainly due to the effect of cavitations when the water is clean. Blade inlet exist local low pressure, less prone to cavitations pressure value; Inlet near the suction surface appears circumfluence when flowering smaller, inlet near the pressure surface appears reflux when flowering high, reflux strength and flow rate have greater relationship. (3) When water was slit-laden, the form and position of inlet damage is the same with clear water, small flow water containing sand blade imported wear damage is near the front cover on the suction surface caused by turbulence hit, near the after cover cavitations damage; Heavy traffic on the surface of the blade inlet pressure when damage is near the front cover by turbulence and the joint action of cavitations damage, the greater the volume fraction of blade inlet flow intensity, the greater the grains of sand particle size which also has certain influence to back flow intensity; at the same time the local low pressure of blade inlet value smaller, and easier to produce experiment.Through this topic for water containing sand of internal flow in a centrifugal pump impeller can help analysis of internal flow pattern by numerical simulation; this paper mainly discusses the characteristics of centrifugal pump water containing sand, for the design and improvement of the Yellow River pump to provide a certain basis. To improve the performance of the impeller and for the further study of centrifugal pump water containing sand flow changes in internal mechanism to provide certain reference, later, to reduce of sands contained stream flow of the blade surface damage problem has important theoretical significance and application value.Through this topic for slit-laden water numerical simulation of internal flow in a centrifugal pump impeller can help analysis of internal flow pattern; this paper mainly discusses the characteristics of centrifugal pump water containing sand, for the design and improvement of the Yellow River pump to provide a certain basis. To improve the performance of the impeller and the further study of centrifugal pump water containing sand flow changes in internal mechanism to provide certain reference, for reducing of sands contained stream flow to the later of the blade surface wear damage problem has important theoretical significance and application value.