Study On Inner Flow Field And Performance Of Centrifugal Pump With Splitter Blades Based On CFD

Centrifugal pump is a commonly hydraulic machinery, which is widely applied in various areas of national economy. When designed according to traditional methods, centrifugal pump has such problems as low efficiency, easy to overload, easy to be hump for the head curve, instability in low flow conditions, vibration and noise and so on, the method of adding the splitter blades is the one of the most effective methods to solve the above problems. Because of the previous studied structure of the centrifugal pump with splitter blades is relatively single, so in the paper, firstly, the long-mid-short blade centrifugal pump, which few studied in the past, was studied, then a new type structure of the centrifugal pump with splitter blades:dual splitter blade centrifugal pump was originality designed and studied, in order to provide a new design idea and method of the centrifugal pump with splitter blades, then how the splitter blades influence on the induced vibration and noise was explored by unsteady numerical calculation. The main work and conclusions are as follows:(1) The IS50-32-125 pump was taken as the model pump to establish a numerical simulation model and determine the computational method, and a variety of turbulence models, mesh sizes and convergence accuracy were discussed. Then the correctness of numerical simulation model and computational method were verified through the centrifugal pump characteristic experimental.(2) The long-mid-short blade centrifugal pump was designed on the base of the model pump, and the orthogonal numerical simulation method was used to study three main design geometric parameters, including inlet diameter of mid-splitter blade, inlet diameter of short-splitter blade, mid-splitter and short-splitter blade bias angle in circumferential direction to obtain the relationship between the geometric parameters and the centrifugal pump performance, then the primary and secondary sequence of the three main design geometric parameters were obtained. The best long-mid-short blade centrifugal pump, which head increase 16.59%～47.15% in the whole range of flow condition than the model pump, which efficiency increase 0.78%～12.67% in the large flow condition than the model pump.(3) A variety of dual splitter blades centrifugal pump were designed on the base of the model pump, by using different geometry parameters such as inlet diameter of splitter blades, dual splitter blades bias angle in circumferential direction and blades number. Then the influence of these geometric parameters on the pump inner flow field and the main performance was discussed, and the best design values were obtained. The best dual splitter blades centrifugal pump, which head increase 15.02%-36.63% in the whole range of flow condition than the model pump, which efficiency increase 1.92%～12.44% in the large flow condition than the model pump, at the same time the head curve become more flat, and efficiency curve shift to the large flow rate, the high efficiency areas is also widened.(4) The four different types of centrifugal pump impeller were unsteady numerical calculated at low flow condition, the best working condition and high flow condition by using the sliding mesh technology, In order to get the pressure distribution condition of the four different types of centrifugal impeller in a cycle, while six monitoring points were set up in the volute flow channel, in order to monitor the pressure fluctuation condition due to impeller rotation, the final results showed that:the pressure fluctuation of long-mid-short blade centrifugal pump and dual splitters blade centrifugal pump in the flow channel is the smallest, thus the two pumps have the best performance of avoiding the vibration and noise.