气—液鼓泡塔中流动域和气含率的分布

利用压力传感器测定了气、液两相鼓泡塔内不同轴、径向位置上压强的脉动信号,分析了压强的脉动特征,计算了各种操作条件下塔内不同轴向位置截面上的平均气含率,发现在不同操作条件下,塔内可能出现不同的流动域分布,即全塔均匀鼓泡域、全塔过渡域、全塔湍动鼓泡域以及均匀鼓泡域,过渡域和湍动鼓泡域中的相邻2种或3种流域同时出现在塔内不同高度上。提出了不同轴向位置流域转变的判据。并发现,同一截面的不同径向位置基本处于同一流域内。同时研究了鼓泡塔内气含率在轴向上的分布规律,给出了不同流动域内气含率的关系式。

DISTRIBUTIONS OF FLOW REGIMES AND GAS HOLDUP IN A GAS-LIQUID BUBBLE COLUMN

Pressure fluctuation signals at different axial and radial positions were acquired and analyzed for a plexiglass bubble column of 285 mm in inside diameter and 4100 mm in height operated with air and tap water.It was found that,under different operating conditions,the whole column may display different flow regime distributions,i.e.,total homogeneous bubbling regime(HBR),total transition regime(TR),total turbulent bubbling regime(TBR)and the neighboring two or three regimes simultaneously at different heights of the column. Schemes of flow regime distribution changing with gas velocity were given.The criteria for flow regimes correlated with operating variables and axial distance above the gas distributor were established.Flow regime at different radial positions across the column was found substantially identical. Gas holdup at different heights of the column was calculated and correlated in different flow regimes as a function of operating parameters and axial distance from the gas distributor.