Numerical Simulation And Cavitation Analysis Of The Flow In Nuclear Cooling Pump Of Pressurized Water Reactor

Advanced pressurized water reactor nuclear power plant construction is the strategic decision for the national response to climate changes and energy issues. To ensure the safety of nuclear power is a top priority in the promotion of nuclear power technology. Nuclear main pump is the "heart" to Nuclear power stations. So ensuring the safe operation of nuclear main pump is particularly important. Nuclear main pump needs long-term rotation in high-speed under high temperature and pressure which make it particularly sensitive to the changes of environment pressures and environment temperature. In the event of cavitation, it will be a serious impact on the pump's performance and life expectancy. In the current conditions, the cost of experiments of nuclear main pump is high. So, numerical simulation is a more economical means which simulates nuclear main pump's flow field and cavitations' situation. This article focuses on the numerical simulation of the nuclear main pump model, in order to analyze the flow rules, cavitations'problems of the nuclear main pump and the impacts on its performance when it has cavitation.Firstly, a brief introduction of the characteristics of the nuclear main pump, nuclear safety and research status at home and abroad is given. Nuclear main pump's function is to drive the high temperature and pressure cycle of the nuclear island, the nuclear fission of the reactor core transfer heat to the steam generator to generate steam, promoting turbine to generate electricity. The environmental pressure achieves 17.2MPa, and the temperature attains 343℃. There are amount of researches in many aspects and multiple levels about the nuclear main pump at home and abroad, but few studies focus on its hollow.Secondly, the computational model of the nuclear main pump is constructed, and the single-phase flow field of the nuclear main pump when it is in the normal operating conditions is simulated. The three-dimensional flow field of nuclear main pump is divided into unstructured computational grids by Gambit software and the flow field is calculated by using the SIMPLEC method developed in the commercial software Fluent. After obtaining the Q-H performance curve under different mesh parameters, a reliable mesh model can be got by comparing the results. Baed on the reliable mesh, the physical quantities in the internal flow field of nuclear main pump, such as pressure, velocity, vorticity, are computed and analyzed.Finally, the full cavitation model is added into the original equations and the possible locations of cavitation can be obtained by simulating the cavitation conditions of the nuclear main pump flow field under the design condition. The break of the first loop accidents and the loss of the heat sink accidents are likely to lead to the occurrence of cavitation. In order to further research the cavitation status of the nuclear main pump, numerical simulations will be taken under the different environment pressures and different environment temperatures. The critical cavitation pressure and critical cavitation temperature can be obtained by analyzing the characteristics of the nuclear main pump cavitation under different operating conditions. Furthermore, the hydraulic performance of nuclear main pump is also impaired under serious cavitation. The given results about the cavitation characteristics under serious cavitation will be not only helpful to analyze the pump's efficiency harm, but also useful for the design and manufacture of the main pump.