FSI Analysis Of Oil Turbo-pump's Rotors For 660MW Steam Turbine Unit

Oil system is one of the most important components of steam turbine unit in nuclear power and thermal power.For the 600MW unit and above,the oil system which consist of main oil pump,booster pump and oil turbine is widely adopted.As one of the key equipments of the oil system,oil turbine pump not only supply a certain amount of pressure oil to main pump but also supply oil to lubrication system,while dynamically maintain the balance of the oil system.Its performance plays a key role in security and stability for the entire oil system.With the huge development of the steam turbine unit,the adaptability and reliability of oil system are increasing,so that it put forward higher requirements for the structural design of the supporting oil turbine and booster pump.As the study of both fluid power design and structural analysis of the oil turbine pump is less in current literature and reports.Based on the fluid-structural coupling analysis of the oil turbine pump in this paper,the basic characteristics of the oil turbine pump's flow field and the dynamic influence of the fluid pressure on structure in work conditions of the oil turbine pump had been achieved,which has great significance for improving the performance,ensuring the safe operation of the unit and the localization and independent innovation of the oil turbine pump.In this paper,the study is supported by Sichuan Province Key Technology R&D Program(2008GZ0072)and Dongfang Steam Turbine Company's R&D projects,combing with the study of key technology on independent research and innovation of the exported oil turbine pump of 60Hz 660MW Steam Turbine units,discussing the "fluid-structure"coupled static and vibration mode analysis of oil turbine pump.First,related theoretical knowledge of rotational parts belonged to oil turbine pump with fluid-solid coupling in 660MW steam turbine unit oil system of DongFang Steam Turbine Units is described.Secondly,based on the study of hydrodynamic characteristics of oil turbine pump's internal flow field,flow pressure on surface of booster pump impeller and oil turbo pump impeller are obtained through numerical simulation analysis inside internal flow field of oil turbine pump.The flow surface pressure is delivered to rotational parts of the oil turbine pump as loads for making the structural statics analysis.In this way,stress and deformation of each rotational part of the oil turbine pump is obtained.And then,structural statics analysis results are employed as initial value to make vibration mode analysis of oil turbine pump rotors under fluid-structure interaction,free vibration frequency and modal shape of oil turbine pump rotors in the medium of air and oil are obtained.According to the "fluid-structure"coupling analysis,the structural characteristics analysis and safety assessment are achieved.The "fluid-structural" coupling analysis results of the oil turbine pump of 60Hz 660MW steam turbine units show that there is a remote possibility from the maximum deformation amount and the maximum stress value to the critical values,the working frequency of the units is much more lower than each order natural frequency and the safe margin is enough.The relative analysis between the rotors in air and in oil proved that the stress and deformation value of the rotational parts in air is lower than in oil,and each order natural frequency of oil turbine pump rotors is lower in oil than in air,but it is still in a very safe range.The calculation results of the case prove that the method and technique route in this paper are feasible.The method adopted in this paper is successfully applied to the exported oil turbine pump of 60 Hz 660MW steam turbine units of Dongfang Steam Turbine Company.It established a technical foundation on domestic independent research and innovation of matching oil turbine pump for large steam turbine units.The method and the technique route not only satisfy the engineering requirements but can shorten the development period and reduce the development cost,and it can be used to design other vane-type fluid machinery.