| Main oil pump is power source and key equipment of oil supply system of steam turbine unit. Its hydrodynamic properties and structural mechanics properties indirectly have mortal influence on operation safety and reliability of steam turbine unit. According to the needs of oil supply system, working pressure of this kind of main oil pump is up to 1.4～2.0MPa, impeller rotating speed reaches to 3000r/min.With increasing in capacity and structural size of steam turbine unit, adaptability and reliability of oil supply system of steam turbine unit is required higher and higher. Not only needs main oil pump achieving high efficiency, but also requires it to adapt to large flowates and work condition changing, and more compact in structure and higher in reliability. Accordingly, they bring a greater challenge to design and improve reliability for main oil pump.At present and in future years, 600MW steam turbine unit is widely used type in thermal power station and nuclear power station. Its oil supply system widely adopted "main oil pump-oil turbine-booster pump" system. As so far, for guaranteeing safety of a large scale steam turbine unit, key equipments of oil supply system of a large scale steam turbine unit usually import from abroad or import technology to make in domestic manufacturer. In order to the subject of this paper combined with requirement of self-development of main oil pump and oil turbine in china, one of key technologies to develop domestic independent innovation development main oil pump matching 600MW steam turbine unit has been studied in this thesis, which is structural dynamic characteristics and reliability of impeller in high pressure flow and high rotational speed environment.According to working condition of main oil pump in oil supply system, internal flow field dynamics model and structural dynamical model of main oil pump were analysed. To ensure reliability of analysis, firstly, commercial CFD software was used to do a numerical simulation for whole flow passage of main oil pump, and to obtain fluid pressure distribution on flow passage surface of impeller; subsequently export numerical simulation results to structural analysis for impeller as load; then, structural static analysis and rotor dynamic analysis have been basically completed by using FSI method. For analyzing difference of mechanical properties of impeller between in air and under normal operation, mechanical properties of impeller in two kinds of medium had been respectively simulated. Considering requirements of actual engineering, structural static analysis and rotor dynamic analysis had been done at condition of 120% working revolution speed for two kinds of medium . Through analyzing these conditions, all kinds of structural mechanics properties of impeller of main oil pump, such as stiffness,strength and modal characteristics,natural frequency and so on have been carried out. According to analysis, reliability and safety of this impeller has been verified. It set up a theory and technology foundation of structural optimization for main oil pump of 600MW steam turbine unit and for developing new type main oil pump also.Combined with structural optimization of main oil pump of 600MW steam turbine unit based on practical engineering requirements in this thesis , FSI method has been used to make structural dynamic characteristics analysis for impeller of low specific speed-double suction-centrifugal main oil pump from an actual engineering. It is proved that precision with FSI is higher than without FSI in structural analysis of main oil pump, and which is not only beneficial to guarantee reliability of pump, but also shorten research cycle and decrease R&D cost. This research has been applied to design of main oil pump by domestic independent innovation and development. This method may be further extended to other kind of turbo machinery, and which has important significance on theory and method of digital design of fluid machinery.
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