Performance analysis of a ball valve used for gas pipelines by introducing nondimensional parameters

The present study deals with the performance characteristics of a ball valve used for gas pipelines by introducing nondimensional parameters. The ball valve has relatively complex flow characteristics on the inside and downstream of the valve, although it has a simple structure as compared with the other valves. The nondimensional parameters, which define the valve operating conditions, are introduced to analyze the nature of the physical properties due to the valve's complex flow. To define the valve flow conditions with respect to valve size, seven nondimensional parameters were selected: pressure ratio, volumetric flow rate ratio, mass flow rate ratio, Reynolds number, Mach number, valve flow coefficient, and inherent flow coefficient. The open-loop type experimental setup is designed to measure the pressure drop and the volumetric flow rate of the ball valve according to the opening rate (angle) of the test valve. Based on the experimental data, obtained by the data acquisition system of the test rig, useful nondimensional parameters to define the nature of the valve performance have been selected and determined. Throughout the experimental analysis of the ball valve, it was found that the nondimensional parameters of pressure ratio, Reynolds number, and Mach number have a similar tendency as related to the valve performance. It can be seen that the intrinsic characteristics of the ball valve are represented by the selected nondimensional parameters, which are defined irrespective of the valve size. The authors proposed a quadratic polynomial for the volumetric flow rate ratio, and the mass flow rate ratio, and introduced the formula for predicting the inherent flow coefficient by the cubic approximation polynomial. It is noted that the nondimensional parameters of the ball valve can be used to determine the performance characteristics with respect to the valve-opening rate and size effectively.