Structural Design And Parameter Optimization Of A New Eccentric Butterfly Valve

Butterfly valve,a type of rotary flat valve,is of the ability to cut fluid flow off and adjust flux in the fluid management systems.It has an widely application in various economic fields nationally based on simple structure,small size and low cost.As three-eccentric butterfly valve has been proposed,butterfly valve overcomes many problems such as the conflicts of the hard seal with leakage and the soft seal with small pressure.The appearance of three-eccentric butterfly valve has broadened the application of butterfly valves and taken place of other kinds of outdated valves.The performance of three-eccentric butterfly valve is not only related to the operation of the control system security and economic benefits,but also has an effect on the developmental direction of valve.It has learned that foreign countries have a monopoly on designing and manufacturing of three-eccentric butterfly valve and we are short of design theories and research techniques.The eccentric butterfly designed independently is not able to be applied to fields with high demands because of the phenomenon of "Shut Down" under working condition of cutting-off.The use-cost of pneumatic butterfly valve increase because additional buffers is needed to work out the serious "Water Hammer" phenomenon.Therefore it is of great engineering value to the analyze and solve problems in three eccentric butterfly valve.A new structure of eccentric butterfly is proposed to solve problems stated before.This dissertation analyzes influence between interference and structural parameters,develops a interference optimization program for structural parameters,analyzes the properties of structure and preference of internal flow of the two kinds of structures with the aid of finite element analysis software.Those have laid a foundation on the structure optimization design and theoretical research method formation for eccentric butterfly valve.Specific contents are as follows:(1)Propose a new structure of eccentric butterfly valve and establish the parametric model of the new butterfly valve and DN250 three-triple eccentric butterfly provided by manufacturer with the aid of the 3-D model software PRO/E.(2)Analyze the coordinate equation of sealing surface in the new structure to solve interference;propose a interference detection method and write programme and interface employing MATLAB.(3)Carry out a secondary development of PRO/E to connect structural parameters and model for a better observation interference test results.(4)Put forward a optimization algorithm to obtain non-interference structural parameters and realize parameter optimization in MATLAB.(5)Analyze the “Shut Down” phenomenon of three-triple structure in a closed state and compare performance of two kinds of butterfly valve by finite element analysis software ANSYS Workbench.(6)Analyze internal flow field of two kinds of butterfly valves under different opening degree numerically by the computational fluid dynamics software Fluent and obtain the performance of two structures.