Numerical Simulation Study on Internal Flow Law and Efficiency of Gas-Liquid Mixed Jet Pump

The Sulige Gas Field is a typical low-permeability, low-pressure tight gas field, where pneumatic jetting is crucial for production. However, existing gas jet pumps have low efficiency, limiting field production and overall development. This paper explores the effect of adding water, at specific volume fractions, to the driving gas on pneumatic jet pump performance. Using Volume of Fluid (VOF) and Computational Fluid Dynamics (CFD) simulations, a three-dimensional fluid domain model was developed to analyze the flow field, turbulent kinetic energy, and energy conversion in the pump. Results show that the water volume fraction significantly impacts pump efficiency, with performance improving over natural gas as the driving medium. The optimal performance occurs at a 0.5 water volume fraction, with efficiency exceeding 40% and a dimensionless mass flow ratio of approximately 2.0. As the volumetric fraction of water increases, the optimal working point of the jet pump (the dimensionless mass flow ratio corresponding to the peak pump efficiency) gradually decreases. It drops from 2.0 at water volumetric fractions of 0.1 and 0.5, to 1.8 at 0.8, and further to 1.5 at 1.0. These findings provide valuable insights for optimizing pneumatic jet performance in the Sulige Gas Field.