Calculation And Analysis Of Flow Characteristic And Hydrodynamic Torque On Triple Eccentric Butterfly Valve

Triple eccentric metal hard seal butterfly valve is a kind of more advanced butterfly valve. It is more resistant to high temperature,It has the higher sealing performance, longer service life, more convenient operation, smaller opening and closing torque and more resistant to high temperature than traditional butterfly valve. So it is able to work in harsher operating conditions. As the working condition of triple eccentric butterfly valve used more and more strict, the demands of various properties of triple eccentric butterfly valve are also becoming higher and higher. Therefore, research of the flow characteristics and the change of hydrodynamic torque of triple eccentric butterfly valve have certain guiding significance to prolong the service life of triple eccentric butterfly valve, improve the operation safety, reliability and stability.This paper using the computational fluid dynamics method and using the CFD aided calculation software to study the flow characteristics of three eccentric butterfly valve and the change rules of the hydrodynamic torque. With DN200 triple eccentric butterfly valve as an example, the internal flow field of triple eccentric butterfly valve is simulated. The hydrodynamic torque and flow characteristic under different conditions and disk opening angles are obtained by numerical simulation.First, under the environment of Solidworks, the DN200 triple eccentric butterfly valve of the three-dimensional entity model and different opening of flow channel models are set up.Second, under the environment of Gambit, the grid models of flow channel under different disk opening angles are set up.Third, the flow field under different disk opening angles and different inlet-outlet pressures are calculated by CFD software. The computed pressure and velocity of flow field are visualized analysis and also analyzed the pressure-flow curve and flow characteristic curve. In addition, from the result of numerical calculation the hydrodynamic torque curve with different working conditions and hydrodynamic torque coefficient curve are obtained.Last, the flow and the hydrodynamic torque experiments were performed on DN200 triple eccentric butterfly valve. After then, through the comparison of simulation data and experimental data the feasibility of numerical calculation model of triple eccentric butterfly valve is verified.The research shows that the flow characteristic of butterfly valve is approximate equal percentage at the opening angle from 30 to 70 degrees. So at the opening angle from 30 to 70 degrees the butterfly valve has better regulation, but at the other degrees the butterfly valve has no regulation. When the opening angle is remained the same, with the increase of pressure drop, the hydrodynamic torque increases approximately linearly. When the pressure drop is remained the same, with the increase of opening angle, the hydrodynamic torque increases, at the opening angle between 65 to 70 degrees the hydrodynamic torque reaches maximum, then with the opening angle increases, the hydrodynamic torque decreases, at the opening angle between 80 to 90 degrees the hydrodynamic torque direction changes.