## 3 Results and Discussion
### Effect of Gas-Liquid Interface on Gas-Liquid Volume Ratio  
Figure 11 shows the variation in the gas-liquid volumetric ratio under different \(D_{M}/D_{N}\) and \(L_{M}/D_{M}\). It can be observed that when \(D_{M}/D_{N}=2\) and \(L_{M}/D_{M}>7.5\) or \(D_{M}/D_{N}\leq 1.75\), the change in the gas-liquid volumetric ratio with increasing \(L_{M}/D_{M}\) is negligible (< 2%). In contrast, as \(L_{M}/D_{M}\) increases, the gas-liquid volumetric ratio also increases correspondingly. When \(L_{M}/D_{M}\) remains constant, the gas-liquid volumetric ratio significantly increases with increasing \(D_{M}/D_{N}\). However, once \(D_{M}/D_{N}\) reaches 2.5, the rate of increase in the gas-liquid volumetric ratio slows down. Figure 11: Gas–liquid volume ratio under different \(D_{M}/D_{N}\) and \(L_{M}/D_{M}\). Figure 10: Variation of gas–liquid type interface and DM/DN with different \(L_{M}/D_{M}\). Figure 9: The instantaneous radius contours of the gas–liquid interface near the mixing section exit under different \(D_{M}/D_{N}\) and \(L_{M}/D_{M}\). Figure 12a illustrates the variation in gas-phase axial velocity under different \(D_{M}/D_{N}\) and \(L_{M}/D_{M}\). By comparing Figures 11 and 12a, it is evident that when \(D_{M}/D_{N}\) remains constant, the trend in gas-phase axial velocity variation with increasing \(L_{M}/D_{M}\) is consistent with the variation in the gas-liquid volumetric ratio. This indicates that the gas-liquid volumetric ratio is primarily influenced by the gas-phase axial velocity. In fact, the entrainment rate is mainly determined by the gas phase and the entrainment near the gas-liquid interface. The entrainment within the gas phase is governed by the combined effects of the gas flow area and axial velocity, while the entrainment near the gas-liquid interface is mainly determined by the axial velocity near the gas-liquid interface (approximately the axial velocity of the gas-liquid interface) due to the relatively small variation in the flow area. Figure 12b displays the variation in radial velocity at the gas-liquid interface under different \(D_{M}/D_{N}\) and \(L_{M}/D_{M}\). The overall trend shows that the radial velocity of the gas-liquid interface gradually decreases with increasing \(L_{M}/D_{M}\), leading to a weakening of the radial flow near the interface and consequently reducing the pressure loss of the gas within the mixing section. Simultaneously, the increase in the length of the mixing section leads to an increase in flow resistance. Therefore, when \(D_{M}/D_{N}\leq 1.75\) or \(D_{M}/D_{N}=2\) and \(L_{M}/D_{M}>7.5\), a smaller mixing section diameter or a longer mixing section results in greater gas flow resistance. The reduced pressure loss due to the increased length at the gas-liquid interface of the mixing section offsets the increased flow resistance, rendering the effect on the gas-liquid volumetric ratio negligible. Conversely, a larger mixing section diameter or a shorter mixing section leads to a lower gas flow resistance, and the reduction in pressure loss due to the increased length at the gas-liquid interface of the mixing section exceeds the increase in flow resistance, resulting in an increase in the gas-liquid volumetric ratio with increasing \(L_{M}/D_{M}\). By comparing Figures 11 and 12a, it is observed that when \(L_{M}/D_{M}\) remains constant, the gas-phase axial velocity significantly decreases as \(D_{M}/D_{N}\) increases due to the increased flow area, while the gas-liquid volumetric ratio significantly increases. This finding is consistent with the results of [PERSON] et al. [13], who demonstrated that the gas-phase pressure loss in the suction chamber significantly decreases as the gas-phase axial velocity decreases, thereby substantially increasing the gas-liquid volumetric ratio. Additionally, the rate of decrease in gas-phase axial velocity is relatively constant.