| The steel mills generate vast amounts of blast furnace gas (BFG) and coke-oven gas (COG) in the production. In order to reduce the energy consumption and environmental pollution, some steel mills build combined cycle power plants (CCPP) to make use of the mixed gas. But in this cycle power generation engineering, gas supply is large, and the flow requirement is up to54000Nm3/h. The control valve is used in delivery lineto contril flow and pressure. The nominal size of control valve is more than7.874in. The flow of gas in control valve is complex three-dimensional unsteady turbulence. This is a tiplcal fluid-structure interaction (FSI) problem between control valve and gas, which would produce great influence on control valve and flow. Therefore accurate analysis of control valve and flow about FSI is important premise in control valve designing, manufacting and optimizing. This article mainly aims at high flow control valve based on FSI in generation engineering.This paper expounds the basic connotation of FSI and research foundation, summarizes the general research situation at home and abroad about FSI. The FSI characteristic of control valve is introduced. The problems of control valve based on FSI that urgently need to be solved in cycle power generation engineering are discussed.The mathematical model of FSI system of control valve is established. Using the finite element numerical calculation method, the structural vibration equation and fluid eauation are analysized. The basic equation and boundary conditions are discussed. The finite element equation aout FSI is established using Galerkin method and the dynamic response is analysed using modal method. Coupling vibration mechanism is revealed. The dynamics characteristic on valve plug is discussed. Low frequency noise coupling mathematical modal is established, which lays a theoretical foundation on further expansion of FSI.The numerical simulation method is used to analyse the FSI system of high flow control valve. The effect of FSI on control valve and flow field is discussed. The mixed gas flow field and veloctity vector distribution in control valve at different opening is revealed. The cause and location of the formation of vortex flow are studyed, and the effect on control valve vibration is analysed. The impact of FSI on pressure and flow is discussed. The model of FSI has a practical significance to improve the accuracy of simulation and analyse the problem of flow inducing vibration. The results provide the therretical guide for optimization design, the noise and experimental research.On the basis of FSI of high flow control valve, flow characteristic and the noise are studied. The flow coefficient and flow resistance coefficient at different opening and noise level are got. And the curves are drawed. The relation of flow resistance coefficient and opening is fitted out using the least square parameter identification method, which realize the valve are good simulation and prediction in a wider condition. The results provide the quantitative data of structure and flow field for optimization design, offer the experimental foundation and theoretical basis for the theoretical analysis. This is basis and necessary measure to reduce noise and optimization.In order to make the structure parameters of high flow control valve and flow field parameters to achieve optimal, using the structure and fluid analysis results as design criteria, the multidisciplinary design optimization (MDO) framework is present. This realizes the integration which involves modeling, analysis and optimization of multidisciplinary and two field control valve. To ensure that gas transmission capacity as the prerequisite, making reducing valve noise as optimization goals, the wall thickness of valve and fluid velocity are reduced. These meet the Reynolds, stress intensity and body total quality requirements. When reducing noise, the product price cost is lowered, flow tends is made to be stable and fatigue strength of valve plug is improved.The dynamic characteristics of control valve body and valve plug based on FSI are analyzed. The effect on natural frequency and vibration mode is achieved and the continuous dynamic response is discussed, which can judge the control valve in different frequency overcome resonance, fatigue and other vibration successfully.Using the analysis of modal and structure strength as the foundation, the structure damage identification method is proposed, which can judge the emergence of crack damage according to the natural frequency and determine how much the size of the crack according to the frequency change. Thus the internal plug damage of control valve in special work environment can be diagnosed fastly and effectively, avoiding the failure of gas leakage and unnormal regulation.Through the test method, the validity of the dynamic model and the reliability of the numerical simulation method is confirmed. The results show that the model has a high precision. Control accuracy of flow and pressure, flow coefficient and resistance coefficient has high accuracy when considering FSI.Studying the control vavle based on FSI can improve the comprehensive performance and realize optimization, which has the important theoretical meaning and engineering practical value for improving the research level of high flow control valve and promoting further development of the cycle power generation engineering.This research is based upon work supported by National high-tech research development plan of China (863plans) under Grant No.2008AA04Z130and by Specialized Research Fund for the Doctoral Program of Higher Education under Grant No.20110131110042. |
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