NUMERICAL ANALYSIS OF BUTTERFLY VALVE-PREDICTION OF FLOW COEFFICIENT AND HYDRODYNAMIC TORQUE COEFFICIENT

Butterfly valves are commonly used as control equipments in applications where the pressure drops required of the valves are relatively low. As shutoff valve (on/off service) or throttling valves (for flow or pressure control), the higher performance and the better precision of butterfly valves are required. Thus it’s more and more essential to know the flow characteristic around the valve. Due to the fast progress of the flow visualization and numerical technique, it becomes possible to observe the flows around a valve and to estimate the performance of a valve. In this paper, three-dimensional numerical simulations by commercial code CFX were conducted to observe the flow patterns and to measure valve flow coefficient and hydrodynamic torque coefficient when butterfly valve with various opening degrees and uniform incoming velocity were used in a piping system. By contrast, a group of experimental data is used to compare with the data obtained by CFX simulation to investigate the validity of numerical method. Researching these results did not gave only access to understand the process of the valve flows at different valve opening degrees, but also was made to determine the accuracy of the employed method. Furthermore, the results of the three-dimensional analysis can be used in the design of butterfly valve in the industry. KEY WORDS butterfly valve, numerical simulation, flow coefficient, hydrodynamic torque coefficient 1.