The Effects Of Guide Vane Changes On The Performance Of The Reactor Coolant Pump

With the rapid development of economy,energy issues have become the focus around the world,the exploitation and utilization of nuclear power have turn into an inevitable trend to adapt to economic development.Driving coolant th at is circulated within the RCP system,referred to as a reactor coolant pump.It is one of the most critical components to ensure safe and reliable operation of nuclear reactors and is a primary unit of nuclear power plants.Reactor coolant pump not only works in high-flow and high-power conditions,but also must be able to withstand high-temperature,high-pressure and strong radiation three-dimensional working environment.In order to improve the performance of the flow components of nuclear main pump,under the premise of safe and smooth operation,model pumps which at a scale of 0.5of the AP1000 nuclear main reactor were taken as the research objects in this paper.The study of the guide vane which is the important flow passage component was carried out:Firstly,under the premise of uniform variation of the guide vane blade of nuclear main pump,the parameters of the model pumps were changed by changing the number of guide vane blade,the thickness of the guide vane and the circumferential rotary angle of the guide vane.Changing the parameters of the model pump by given the original model data and experience.Then studying the effects of the performance of nuclear main pump which were caused by the uniform changes of guide vane are investigated.The results showed that under the design condition,only one parameter of the number of guide vane blade,the thickness of the guide vane and the circumferential rotary angle of the guide vane is changed,and the other design parameters are unchanged.When the thi ckness of the guide vane is the original thickness and the circumferential rotary angle of the guide vane is 8 °,the head and efficiency of the pump is the highest.And internal flow field distribution of the guide vane passage and discharge chamber are m ore uniform.The capacity of guide vane that eliminates flow velocity circulation is better and the hydraulic loss in guide vane is less when numbers of guide vane blade is 16,guide vane thickness is thickened 1.5 times and guide vane circumferential rota ry angle is at 16°.It illustrated that the speed of flow velocity circulation at guide vane outlet is not as small as possible,and there is the best flow velocity circulation at guide vane outlet which leads to better performance of pump.The best flow velocity circulation at guide vane would make the liquid flow close to the wall better,prevent the separation of flow.So as to make the liquid flow is more uniform and smooth,and improve the overall performance of the pump.Secondly,the paper also focused on the effects of thickness of the guide vane blade on the performance of nuclear main pump.In contrast to the previous research,the thickness of the guide vane blade was non-uniformly thickened under the condition of considering the strength of the b lade structure and the exclusion of the guide vane.Only changing guide vane blade thickness,the performance of reactor coolant pump with five different guide vane blade thickness are predicted by numerical simulation.The results as follows.Under design condition,the guide vane blade thickness which under 0.5 times even thinning,excretion between the guide vane is reduced.However,the flow conductivity and the capacity of energy conversion decline.The head and efficiency of the reactor coolant pump f all eventually.Compared with other four projects,when the front half part of the guide vane blade are thickened 1.5 times,its flow field is more uniform,the flow losses in guide vane is the least,the head and efficiency of the model pump are the highe st.Under the prerequisite of having met the guide vane blade structural strength,guide vane blade can be thickened non-uniformly according to the different position of guide vane runner.Then the hydraulic loss between guide vane passage is reduced.At the same time,transforming kinetic energy into pressure energy fully.The internal and external characteristics of the reactor coolant pump can be improved consequently.Finally,this paper studies the non-uniform diffusion of guide vane blade.By observing the true flow of the guide vane and the volute.It was found that the flow of the guide vane near the right tongue and the tongue which is at the right side of the volute were the most disturbing.Therefore,arranging the guide vane near the right tongue non-uniformly.Rotation of this guide vane blade was carried out by +5 °,-5 °,+ 10 °,-10 °,+ 15 °,-15 °.This creates a non-uniform diffusion of the guide vane.The result show that when the rotary angle ? = +10 °,the head and efficiency of the nuclear main pump are the highest,the lowest is at ? =-5 °.The maximum difference between efficiency is 3.86%,and the maximum difference between head is 1.60 m.Also at ? = + 10 °,the hydraulic loss in the guide vane and volute is the least.At the same time,observing the internal flow field of the nuclear main pump,it is not difficult to find following results.Under the design condition,at ? = +10 °,the distribution of the streamline of the guide vane outlet is the most uniform and smooth.The range of turbulent kinetic energy is the smallest.In the outlet of the chamber,the secondary flow phenomenon of the velocity distribution is also improved obviously.And the distribution of the three-dimensional streamline in the volute is more uniform than the other schemes.It is shown that the distribution of the blade vane at this time can better rectifies the liquid flow and delivers the liquid flow to the chamber.Reducing the hydraulic loss in the guide vane and the pressurized water chamber effectively.Improving the flow state in the pump and increasing the performance of the nuclear main pump.