Study On The Affect Of The Cascade Solidity To The Efficiency Of Multiphase Pump

Multiphase transport technology,which has been developed in recent years, is an efficient and economical way for oilfield exploitation. Multiphase pump is the core equipment of multiphase transport technology, and it is a multiphase conveyer having the function of the conventional pumps and gas compressors. As the key component of the multiphase pump, the impeller decides the inner flow stability and the pump efficiency directly. Cascade solidity, which has a direct infection on the pump efficiency, is an important geometric parameter to the impeller. Therefore, the research on the cascade solidity of the impeller is special significant.The numerical simulation was performed on the single-channel impeller method in the thesis. The infection of the cascade solidity on the efficiency of multiphase pump was analyzed based on the simulation results of the impeller field. The best cascade solidity was found for the efficiency and performance of gas-liquid mixing flow level. The 791-airfoil was applied for it is suitable for the multiphase flow requirements inside the pump. The three-dimensional model of the single-channel impeller was established with the Software UG NX, the calculation area discretized in the software Gambit and the calculation is carried out with the software Fluent6.3.The simulation results showed that when multiphase pump impeller cascade solidity reduced, the pressure difference between the two surfaces of blade would increase, which was likely to trigger the gas-liquid separation in the channel, and the transport ability of gas-liquid mixed flow in the pump declined. An appropriate increase in the cascade solidity could supply a smooth pressure rising along the airfoil, and slowed down the phase separation on the flow direction. The simulation results of the five impellers with different cascade solidity were compared on the high gas volume fraction. When the cascade solidity on the hub and shroud were all 2.4, the assembly of the parameters had the best performance. Although the phase distribution was not even enough, the strongest compressing ability, the highest efficiency, the proper shaft power, and the maximum gas rate range were obtained. The overall performance was much better than other models. The characteristic curves of the single-channel impellers with different cascade solidity and the best model are drawn, helpful reference materials are provided for the development and research of the overall unit, and the development cycle of the helico-axial oil-gas pump is reduced by the research of the thesis.