| Pressure reducing valve are widely applied in the water diversion,urban water supply,hydroelectric power and other industries.It has been more than 10 years of history for application of intelligent pressure reducing valve in abroad,which has achieved good economic benefits in the water supply enterprises.Recent years,domestic valve enterprises have made significant progress in designing and manufacturing of the pressure reducing valve by introducing foreign technology,but the market of intelligent pressure reducing valve is leaded by foreign factories,there is a certain gap with foreign technology in the intelligence level,core technology,manufacturing technology,product performance,etc.At present,the concept of industry 4.0 represented by Germany,portrays a fine blueprint for the industrial development of contemporary foreign advanced countries.However,China launched the "made in China 2025”,which announced the country determination of developing intelligent manufacturing engineering and intelligent equipment.To improve the performance and intelligence level of the pressure reducing valve is an important mission today,not only meet the user requirement of better quality and profit,and also accord with the national industry policy.Depended on the sub topic of water pollution control and improvement of 12th five-year national science and technology key project-Intelligent pressure management integrated equipment based on real-time feedback of flow and pressure,research the intelligent pressure reducing valve of urban water supply in the paper.The main contents of this paper are as follows:(1)On the basis of analyzing the structure of traditional pressure reducing valve,researched the components and functions of intelligent pressure monitoring system,designed the intelligent pressure reducing valve and intelligent pressure monitoring system.Researched the principle of intelligent pressure control and pressure maintenance,got the deviation expression and transfer function block diagram.Compared the plans from several aspects such as power consumption,reliability and service period,the optimal plan is determined.The design of the intelligent pressure reducing valve monitoring system is fulfilled,the general system design of hardware and software was determined.The detail design was discussed from five aspects:valve design,integrated circuit design,software design,communication design and hydraulic system design.(2)Using the method of engineering cybernetics,the pilot valve,the traditional pressure reducing valve and the intelligent pressure reducing valve were analyzed and the mathematical model is established to obtain the time domain differential equation and the complex domain equation.The Amesim model of the pilot valve,the ordinary pressure reducing valve and the intelligent pressure reducing valve were established respectively.The static characteristics and dynamic characteristics were researched.The simulation parameters such as the pressure regulating range,the rise time and the stroke were simulated,and the feasibility of design was verified.By studying the open-loop system stability of the pilot valve,traditional pressure reducing valve and the intelligent pressure reducing valve,the stability of the corresponding closed-loop system is obtained.(3)The piston dimension of the intelligent pressure reducing valve affects the dynamic performance,and the diameter of the actuator affects the pressure maintenance performance of the pilot system,thus impact the pressure precision of pressure reducing valve.The optimal design method is used to optimize the piston size and the actuator diaphragm size of the intelligent pressure reducing valve respectively.The optimization of the piston size can not only balance the safety factor of the opening and closing direction,ensure the dynamic performance of the main valve,but also reduce the weight and manufacturing cost.The optimization of the actuator reduces the pressure difference between the actuator and the upstream and downstream,effectively improves the operating conditions of the solenoid valve,reduces the leakage of the solenoid valve so that the pressure maintenance performance and outlet pressure stability improved.(4)The theoretical model of the flow coefficient calculation of the intelligent pressure reducing valve is established,the Computational Fluid Dynamics(CFD)analysis method was compared with the theoretical calculation method.The series of CFD models were used to study the flow characteristics of the pressure reducing valve under different hole distance and different hole dimension.The cavitation is studied and compared by cavitation and multiphase flow model combined.The study of frequency and noise is carried out by large eddy simulation and acoustic composite model combined.A comparative study of flow coefficient,dissipation rate and flow velocity was carried out by turbulent model.It is concluded that the small hole diameter and large hole spacing have relatively optimal flow characteristics.(5)Adopt the artificial chemical reaction optimization algorithm(ACROA)to optimize the parameters of support vector regression(SVR),the parameter optimization method for SVR based on ACROA(ACROA-SVR)was proposed.Furthermore,the ACROA-SVR was applied to the pressure prediction of the diaphragm cylinder pressure herein.By analyzing the experiment data,ACROA-SVR was compared with SVR based on genetic algorithm(GA-SVR)and traditional SVR,the feasibility of ACROA-SVR used for the core control algorithm of intelligent pressure reducing valve was demonstrated.(6)In order to verify the correctness of the theory studied in this paper,the feasibility of the design scheme and the reliability of the prototype,a small liquid test bed was built and the simplified intelligent pressure reducing valve was experimented to verify the feasibility of the control algorithm.Adopted the prototype to experiment on the water supply pipeline separately in the Urumqi Water Group,Guangdong and Hong Kong Water Supply Co.,Ltd.,which have carried out the pressure maintenance test and pressure regulating test equipped with or not the accumulator,the experiment results testified that the intelligent pressure reducing valve principle is feasible and the performance parameter achieved the design goals;water pressure of valve inlet fluctuate each day regularly,while the water pressure of the valve outlet fluctuate with short period simple harmonic wave irregularly,which synchronize with the main valve piston chamber(upper chamber)pressure;can do the fault diagnosis of the pressure reducing valve according to the pressure regulating period and skew time. |
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