Numerical Investigation of Flow Induced by a Gate Valve in the Slug Regime

Slug flow is a part of an intermittent flow that is avoided in industrial applications because of its irregularity and high-pressure fluctuations. The present investigation aims to comprehend the behavior of intermittent slug flow with the gate valve and its associated pressure drop, slug liquid holdup, slug frequency, and averaged slug body length using CFD simulation studies. To achieve this objective, numerical investigations of slug flow were carried out on a horizontal pipe 10 m in length and 20 mm in diameter with three distinct area contraction ratios. First, the numerical results (slug frequency) were validated by comparison with other studies, and a reasonable agreement with an error of less than 3% was achieved. Second, the numerical results were validated by comparison with experimental data in terms of time and space for slug flow encountering the gate valve, and a sensible agreement with an error of less than 15% was achieved. Eventually, pressure gradient, slug frequency, slug length, and the existence of a gate valve have been investigated using numerical methods. The results showed that the slug frequency increases by 4.3% and this phenomenon is due to the small waves that occur due to the high pressure drop at the valve location. The length of the liquid slug increases by 20.89 percent by reducing the opening of the gate valve and decreases by 30.4 percent by increasing the surface velocity of the gas. By increasing the distance from the gate valve, the pressure drops decrease by 15.65%.