Numerical Study on the Commissioning Charge-Up Process of Horizontal Pipeline with Entrapped Air Pockets

Accurately predicting hydraulic characteristics in the charge-up process of horizontal pipeline with entrapped air pocket is of great significance for the process design and field operation of the oil pipeline commissioning. In this paper, this process is simulated and its hydraulic characteristics are analyzed. Finite difference method and characteristic method are combined to obtain the velocity and pressure field of the whole line. Results show that when air pockets reach the outlet of the pipeline, they blow out tempestuously and the velocity of gas may reach tens times of its normal flow velocity. At the beginning and end of the blowing out, velocity and pressure of the whole line suffer acute change. Based on this, the influence of several critical parameters is compared and analyzed by several groups of examples.