The Simulation And Experiment Investigation On The Valve Working State Using The Method Of Transient Inverse Problem

Serving as the hydraulic adjustment element of pipe network, the valve which could maintain its working state is set to ensure the stable operation of the pipe network. For the complex pipe network system in the city, it is equipped with many valves to ensure its stable operation and achieve its functional requirements. Sometimes, for the valves buried in the ground, the actual working conditions are different with working conditions. Because the local resistance coefficient of the valve can change a lot with its working conditions variation, which will cause change of the hydraulic conditions, affect its functional requirements and then cause unnecessary waste of hydraulic pressure. Therefore, it is very important to seek an approach that determine the valve actual working condition.This paper establishes the analysis model focusing on the problem that analyze the actual working conditions of valves, which belong to the pipeline systems. The analysis model is based on Inverse Problems Analysis of system identification theory. In the simulation analysis and experimental research, some models are researched, in which the valves are in different open state and there are many valves. By comparing simulation results with the experimental results obtained and analyzing the valve, which are in different state, influence on the transient flow pressure can be acquired, and providing the basis for analysis the valve actual working condition by Inverse Problems Analysis. The valve can cause loss of flow transient pressure energy, and as the decreasing of the degree of valve opening, the wave energy loss will be intensified; In addition, the valve will also lead to fluctuation interference phenomenon, and as the decreasing of the degree of valve opening, the fluctuation phenomenon will be intensified.Based on obtaining the regularity of transient flow pressure in the influence of the valve working condition, the transient flow is generated as incentives of the system. The pressure obtained by pressure detector is chosen as response to the system and the working conditions of the valve is the system parameters to be identified. A mathematical model is set up to analyze the valve working state, which is based on the method of Inverse Problem Analysis and L-M algorithm. An optimized solution model is established by solving the minimized the measured pressure and calculating values. The optimization model is solved by the Newton Raphson algorithm and genetic algorithm. Then applying the model to analysis the experimental pipeline valve working condition. The research confirms that it is feasible to apply the theory of transient glow to analyze the valve working condition. In addition it is concluded that genetic algorithm has a larger search space, gets higher precision, and is more applicable in practical engineering pipe network, when it deals with multiple variable.