Large eddy simulation of the two-phase flow pattern and bubble formation process of a flow mixing nozzle under a gas-liquid mode

The micro-bubbles can be stably generated in the flow mixing nozzle under gas-liquid mode, which has broad applications, but the study of its flow morphology remains insufficient. This paper assesses the flow pattern and bubble formation process of the flow mixing nozzle under gas-liquid mode using a combination of the large-eddy simulation method and the volume of fluid method. Compared with the liquid-gas mode, the flow pattern in the gas-liquid mode is relatively simple, with only three flow patterns: bubbly flow, breakup, and their transitional flow patterns. The results demonstrate that the main factors that change the flow pattern of the flow mixing nozzle under gas-liquid mode are the inertial force of the two-phase and the density difference between the two phases. The nozzle mixing zone area is defined as the characteristic area scale, and the ratio of the bubble sectional area and nozzle mixing zone is used as the bubble characteristic. The fitting curves of the bubble characteristic and the gas-liquid relative inertial force are also provided.