Flow Characteristic Analysis And Flow Coefficient Calculation Program Design For Spray Pressurizer Valve

Pressurizer spray valve is an important device for regulating pressure of nuclear power plant reactor.It is used to stabilize the pressure,concentration and temperature of primary loop medium,and it’s the guarantee for safe and stable operation of nuclear power station.The pressure difference between inlet and outlet is small,which requires high flow performance,and requires continuous spraying when closed.Until now,the pressurizer spray valves adopted by domestic nuclear power plants are still imported.Therefore,the analysis of the flow characteristics of the pressurizer spray valve has certain scientific significance and engineering value for promoting the technological progress of China’s nuclear power valves and breaking the foreign technology blockade and product monopoly.The main research contents and achievements are as follows:(1)The numerical calculation model of pressurizer spray valve is established,and its flow characteristics and flow field were studied by numerical simulation.At the same time,its flow characteristics were studied through the test method.The research showed that the flow characteristics of the pressurizer spray valve are equal percentage flow characteristics,which coincide well with the ideal percentage flow characteristics at larger opening.The velocity of the fluid increases with the increase of the valve opening,and there is a large vortex in the pipeline downstream of the valve,but it gradually decreases with the increase of the valve opening.The pressure drop increases with the increase of valve opening,and the maximum negative pressure is always obtained at the valve core.The maximum error of the relative flow coefficient is 6.498%,which verifies the accuracy of the numerical simulation.(2)The influence of structural parameters on the flow characteristics of pressurizer spray valve was explored by numerical simulation,and the structure of pressurizer spray valve for CAP1000 nuclear power plant was designed.The results show that compared with the small hole type and the straight-groove type,the V-groove type has better regulation performance and wider applicability.With the increase of valve core angle,the flow performance of the valve increases,and the flow characteristics still meet the equal percentage flow characteristics.Reducing the height of the flow passage will make the flow characteristics of the valve close to the linear flow characteristics at large opening.Reducing the size of the valve seat will reduce the flow performance and regulation performance of the valve,and the pipe diameter has little effect on the flow performance of the valve.The design of the pressurizer spray valve structure can better meet the actual working conditions in terms of flow performance.(3)The relationship between the flow area of V-ball valve and its opening and structural parameters was obtained by mathematical calculation,and the relationship between flow coefficient and flow area was explored by using the proportion method,formula+ fitting method and fitting method respectively.Based on the fitting method,using C language and Windows program design,the calculation software of flow coefficient of V-type ball valve is developed.Finally,the accuracy of the software was verified.The results show that the software can better predict the flow coefficient of V-ball valve,and the calculation accuracy meets the engineering requirements.