搅拌槽内粘稠物系的混合过程

以发酵罐中通气搅拌下的混合为背景，考察了搅拌形式，物系流变性质及通气速率等因素，对搅拌槽内粘稠物质系中混合过程的影响，轴向流翼型混合效率高于涡轮桨，通气有助于改善粘稠物系中的混合粘度变化主要改变槽内流动状态和桨叶泵送能力，从而改变混合效率，当物系为中等粘度假塑性流体时，混合速率由桨叶泵送流动的流量和形态所决定，多层搅拌下分区现象限制了混合速率。

Bulk Mixing in Viscous Media in Mechanically Stirred Vessels

Mixing characteristics of a new type of axial flow hydrofoiler was studied in stirred vessels. Based on the background of bulk mixing under aeration and agitation in industrial fermentors, the effect of impeller configuration, medium rheology and aeration rate on bulk mixing was investigated. It was experimentally found that: (1)The advantage of axial flow impellers over Rushton turbines on bulk mixing is clearly shown by the rate and mode of their pumping flow, especially under agitation by multiple impellers; (2)Aeration can intensify bulk mixing in viscous media and the differences of various impellers in mixing efficiency tend to decrease under aeration; (3)Change in viscosity of test fluids alters principally pumping flow of impeller and therefore influences bulk mixing. In viscous media agitated by multiple impellers, bulk mixing rate is seriously decreased due to compartmentation phenomena between impellers. Mechanism of bulk mixing in viscous media has been proposed, which can explain the effect of aeration on bulk mixing.