开槽式圆盘涡轮搅拌器的气液分散特性

在直径为0.49 m的平底有机玻璃搅拌槽中,针对开槽式和未开槽式半圆形(SHY,HY)和抛物线形(SBTD,BTD)涡轮搅拌器进行研究,表明叶片开槽对气液二相体系中临界分散、通气功率和气含率(含气体积分数)的影响。结果表明:由载气到气泛测得的泛点比气泛到载气测得的泛点明显滞后;对比相同条件下2类搅拌器的通气功率和气含率,在相同通气准数下,开槽式搅拌器表现出功率消耗(Pg/P0)较未开槽搅拌器下降幅度增大,曲线形式改变明显的特点;在相同功耗下,开槽式搅拌器有气含率高的特点,以SBTD为例,其要高于BTD 3%左右,SHY也要高于HY。综合以上特点,开槽式搅拌器值得被推荐用于工业气液搅拌反应器中。

Gas-liquid dispersion characteristic of slotting blade disk turbines

The influences of impeller(slotting or not)on the properties of gas dispersion,gassed power consumption and gas holdup(volume fraction) were studied in a 0.49 m stirred tank agitated by semicircle and parabolic blades disk turbine,which were identified as HY(SHY) and BTD(SBTD).The results show that the flooding transitions measured from loading to flooding(L-F) show a hysteresis compared with that measured from flooding to loading(F-L) with increasing and falling gas rates.Comparing the gassed power consumption and gas holdup between the two kinds of turbines,and under the same flow number,the slotting impellers have lower relative power demand(Pg/P0),and the power curves change a lot.At the same power consumption,the slotting ones have higher gas holdup,for example,SBTD,which is about 3% higher than BTD impeller over a wide range of gas rates;SHY is also higher than HY turbine.Therefore,the slotting turbines are worthy of being recommended to the industrial application of the gas-liquid stirred reactors.