Calculation of the flow characteristics of a pipeline with an intermittent air source while considering the dynamic change of flow area of a ball valve

The method of characteristics used to solve a one-dimensional unsteady flow field of a simplified pipeline model were used to study the gas flow characteristics of a pipeline and the change in pressure in a container with an intermittent air source of a gas bearing test-bed, in particular, the pipeline flow velocity and pressure changes were analyzed. The flow area of the ball valve increased gradually as the valve was in the process of opening. The dynamic process of opening the valve and the reduction of pressure in the container with the air source during the operation were taken into account in the calculations used in the model. The program employed the FORTRAN computer language. The results show that the model used here is able of calculating the change of pressure and gas mass of an intermittent air source and the flow characteristics of pipeline. The method of characteristic can satisfy the requirement for accuracy and computational speed. This study provides a possible approach for the further study and optimization of this process.