Numerical Research Of The Flow In The Nuclear Main Pump Based On The Sliding Mesh Method

With the rapid development of nuclear power in China, the step of domestic production with major equipment has been accelerated. Nuclear reactor coolant pump, namely nuclear main pump, is the only rotating equipment with high-speed in the nuclear islands, and also, known as the heart, its reliability affects the operation safely of the reactor directly, so, it belongs to the level of nuclear safety according to the United States ASME. Due to the harsh environment in which nuclear main pump rotating with high-speed, such as high temperature, high pressure and strong radiation, it’s important to research the law between coolant and hydraulic components for designing and operating safely.Numerical method using for the research of information in the flow field has been applied more and more widely in the current technical conditions. The unsteady flow had been calculated for nuclear main pump based on the sliding mesh method, the law had been analyzed during the variable environment, the critical condition allowing for cavitation had been explored, and also for its impact on performance.The transient characteristics of pump flow can be reflected by unsteady calculation, as for the design condition, the head calculated from nuclear main pump shows a fluctuation phenomenon when at the rated speed, strong interaction existing when attention paid to the whole passage, especially between the impeller and guide vane.As we known, the break of loop accidents is likely to cause cavitation, the paper presents a3D unsteady flow through changing the environmental pressure. The results show that reducing environmental pressure will lead to cavitating on the suction blade. It’s necessary to make sure the critical cavitation because of operating environment changing with time. The numerical results show that, there is no cavity occurred above16.2MPa, starting from the range, the suction surface of blade has been seen cavitation, first appeared in blade entrance mainly. With the decline in environmental pressure, cavitation region become large until covering almost half of the blade in which hydrodynamic performance decresed significantly. The simulation results based on the sliding mesh further confirmed the critical condition of vaporization occurring.