Investigations Of Flow Characteristics For Two-phase Slug Flow Under Rolling Condition

The experimental research about the slug flow characteristics in stagnant and flowing liquid through vertical tube under steady and rolling state were carried out respectively.The relation between the slug flow and the general trend of pressure signal cure in stagnant liquid under steady state was explained, and the impact of the entrance pressure on the slug bubble rise velocity was analyzed. Besides,the effect of different water and gas flow rate on slug bubble rising velocity in the flowing liquid under steady state was analyzed. And the slug bubble rising velocity in stagnant and flowing liquid under rolling state was analyzed.Through the analysis of experimental data, it was found that, the different entrance pressure did not affect the slug bubble speed in the stagnant liquid under steady state, and the increase of slug bubble rise velocity mainly depends on the increase of the gas-liquid two-phase mixture velocity in flowing liquid under steady state .The slug bubble rise velocity in the stagnant liquid under rolling state is larger than it in the stagnant liquid under steady state. Moreover, the relationship between the average bubble rise velocity and gas-liquid two-phase mixture velocity is a linear function.Based on the experimental data, the slug bubble velocity expression was given in stagnant and flowing liquid under steady state, which fit the empirical formula well by contrasting. Moreover, the slug bubble average velocity expression in the stagnant and flowing liquid under rolling state was given .And the calculated results are in good agreement with experimental data. Besides,the average void fraction correlation of slug flow is fitted. By comparing the average void fraction calculation and experimental data of slug flow, it is found that, this correlation can well predict the average void fraction of slug flow well under rolling condition.