推进桨、45°三叶折叶桨及新型轴流式桨的流场分析

Fluid-Field Analysis of Impeller, Traditional Typical Three-Blade and JH-Type New Axial-Flow Impeller

对推进桨 4 5°三叶折叶桨及新型扭弯轴流式搅拌桨———JH桨的三维流场进行了激光测速实验 ,结果分析表明 ,4 5°三叶折叶桨其轴向流场分布不均匀 ,而是“W”形 ,其周向速度随半径成正比 ,易于打漩 ,径向速度随半径增加较快。说明 4 5°三叶折叶桨是以轴向流为主伴有一定径向流场的一种桨型 ;推进桨轴向速度流场均匀 ,但随着离桨距离的增加其均匀性下降 ,且轴线附近存在有低速区。其径向速度虽然在桨径范围内较小 ,但在桨径外仍有一定值。其周向流场分布较均匀 ,说明推进桨也非“纯”轴流式桨 ;JH桨轴向流场均匀 ,随着离桨距离的增加其衰减速度减慢 ,其径向速度分布均匀 ,且较小 ,而周向速度在桨径以外迅速衰减 ,并随离桨距离的增加迅速衰减。说明JH桨是一种以轴向流场为主的桨型 ,它比推进桨轴流特性更好 ,更不易产生打漩现象 ,是溶解、悬浮搅拌的理想桨型。

The three dimension fluid flow fields of impeller, traditional typical three-blade impeller, and JH-type new axial flow impeller have been tested by using laser instrument. The analysis results show that the axial flow field of traditional three-blade impeller is not uniform but with W shape, it's radial speed is propotional to radius, impeller with this type is easy to make verten its circular speed increasing as radius increasing is very great. This indicates that this impeller is a type of impeller which has axial fluid flow field as main field and circular fluid flow field as company field. The axial speed field of impeller distributes uniformly, but the uniformity decreases as the increase of distance to impeller. There is low speed area near the axle, its radial speed field is small but still exists beyond the blade radius. This shows that impeller is not an impeller with pure axial speed field. The axial speed field of JH impeller is uniformly distributed and decreases slowly as increase of distance to impeller blades. Its radial speed is uniformly distributedu too, and is small. Its circular speed decreases quickly as increase of distance to blade. This shows that JH impeller is a type of impeller which takes axial speed field as main field, it is not easy to make verten, therefore this type of impeller is the ideal impeller for process of dissolving, emulsifying and suspending.