Influence of gas volume fraction on vortex street generation in downhole Oil-gas Two-phase flow

Abstract Vortex flowmeters are suitable for measuring flow rates in downhole environments due to their stability and wide applicability. However, the variability of the downhole environment and the complexity of fluid components severely impact the accuracy of flow measurements. To address this issue, this paper employs numerical simulation methods and uses the VOF model to analyze oil-gas two-phase flow. The results indicate that in two-phase flow, vortex flowmeters can be used for measuring oil-gas mixtures, and when the gas volume fraction is within 12%, the vortex-shedding frequency exhibits a linear relationship with the gas volume fraction. Additionally, it is found that the normalized power of vortex-shedding decreases in an approximately S-shaped curve with increasing gas volume fraction. These conclusions provide guidance for the subsequent calibration of flow rate data.