The Analysis On Regulating Valve Circulation And Erosion Mechanism Of The Pipeline

A regulating valve is installed in the piping system in a power plant, It plays a vital role in safety and stability of the entire system. Flow area is an important design parameter of the regulating valve, because of a close relationship between flow coefficient and valve flow area, it is significant to calculate the flow coefficient. According to the proposed method in the paper, we designed the structure of the walve. In one condition, we found that erosion occurred on the surface of the board which connect the exit of the walve. To ensure the safety and stability of the system, it is necessary to analyze and certificate the reasons of the erosion. Using CFX to simulate cavitation of the walve pipe is an effective method. The paper mainly accomplished the following works:①Based on the basic principles and the basic equations of fluid mechanics, we selected a more appropriate turbulence model, use the CFX which is a computational fluid dynamics software to calculate the valve flow coefficient. We drew a curve of the flow coefficient which varies from different degrees of opening and verified the correctness and accuracy of numerical calculations.②We design the structure of the walve around its circulation features. Based on the close relationship between the average circulation characteristics and regulating valve flow area, we establish a set of complete procedure to design structure of the walve. The method in this paper has shorter design cycles, is more accurate than others, is lower costs than others.③Based on the basic equations of fluid dynamics, suitable turbulence model, bubble dynamics model, the Rayleigh-Plesset cavitation model, to analyzed the reasons of the erosion, we simulated the process of the cavitation. proposed several ways to reduce erosion.④According to the results of CFX numerical calculation, we put forward a method of predicting the erosion of the board, establish a erosion prediction model, Quantitatively predicted the erosion rate of the board. We obtained a consistent result compared with the measured result.⑤ Pressure of inlet has a great influence on the flow field,descript the flow field of three conditions which are different from pressure. Analyzed the influence of pressure boundary condition.The method used in this paper has theoretical guidance to design the structure of the regulating walve and to analyze the similar erosion problems.