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多相搅拌过程中常常根据临界搅拌转速表征搅拌效果。由于各种搅拌桨的功率准数不同,低临界转速的搅拌桨对应的搅拌功耗可能大于高临界转速的搅拌桨,因此,本文提出用临界功率作为表征手段。选取表面曝气和固体悬浮2个典型的多相搅拌过程进行了验证,结果表明:(1)在表面曝气过程中,达到临界曝气时六斜叶下推圆盘涡轮(PBRTD)桨的搅拌功耗比标准Rushton(RT)桨低,相同功耗下PBRTD桨的kLa也更高,与临界曝气转速的判定结果不同,临界功率法认为PBRTD桨更适合作表面曝气桨,这与表面曝气机理的认识相符;(2)下推折叶透平(PBTD)桨和三叶后掠(TBHA)桨的固体颗粒悬浮实验结果也表明TBHA桨的临界离底悬浮转速高但功耗更低,TBHA桨的整体循环能力更强,有利于固体悬浮。
In the process of heterogeneous mixing, the stirring effect is often characterized according to the critical stirring speed. Due to the different power standards of various paddles, the stirring power corresponding to the paddles with lower critical speeds may be greater than the paddles with high critical speeds. Therefore, the critical power is used as the characterization method. The results show that: (1) During the surface aeration, when the critical aeration is reached, the PBRTD impeller Compared with the standard Rushton (RT) paddle, the kLa of the PBRTD paddle is also higher under the same power consumption, which is different from that of the critical aeration speed. The critical power method holds that the PBRTD paddle is more suitable for the surface aeration paddle, Surface aeration mechanism. (2) The experimental results of solid particles suspension on PBTD propeller and TBHA propeller also show that TBHA propeller has high critical suspension velocity but low power consumption Lower, TBHA paddle overall cycle capacity is more conducive to solid suspension.