疏水Rushton搅拌桨的减阻性能

为了减小搅拌阻力与功耗，本研究提出了疏水叶片搅拌桨的设想。首先采用数值模拟的方法，对非疏水Rushton桨搅拌容器内的流场进行了模拟，通过与文献中实验结果的对比，验证了数值模型和模拟方法的可靠性。随后研究了湍流状态下疏水Rushton搅拌桨的流体动力学性能，分析了不同疏水状态下的流场结构、剪应力和压力分布以及减阻效果和搅拌功耗，并与非疏水桨进行了对比。结果表明，疏水处理后Rushton桨搅拌容器内的流场没有明显变化，但流体的轴向泵送能力有所增强，高速度区域略有扩大，超疏水时效果更明显。疏水处理可降低Rushton桨的剪应力和桨叶前后表面间的压差，具有减阻效果，超疏水时减阻幅度高达39.56%。另外，疏水Rushton桨的搅拌功耗有所降低，与非疏水桨相比，超疏水桨的功率准数降低了8.53%，具有显著的节能效应。

Drag reduction performance of a hydrophobic Rushton impeller

For the purpose of reducing drag and power consumption during the stirring of fluid within the vessel, a hydrophobic Rushton impeller was proposed. Firstly, flow field in the vessel stirred with a non-hydrophobic Rushton impeller was numerically studied. Through comparison with the experimental results from literature, the reliability of the numerical model and the simulation method was verified. Subsequently, the hydrodynamic performance of the hydrophobic Rushton impeller under turbulent flow regime was simulated. The flow field, shear stress and pressure distribution, drag reduction effect and power consumption under different hydrophobic conditions were analyzed, and comparisons were made with their counterparts of the non-hydrophobic Rushton impeller. Results showed that although the flow field was not significantly changed, the axial pumping capacity and the high velocity area within the impeller discharge flow region were slightly increased, especially for the super-hydrophobic Rushton impeller. For the hydrophobic Rushton impeller, the wall shear stress and pressure difference between the front and rear surfaces of the blades were reduced. Besides, the drag reduction effect was observed and the drag reduction ratio of the super-hydrophobic Rushton impeller was as high as 39.56%. Besides, power consumption of hydrophobic Rushton impeller can be reduced. Compared with the non-hydrophobic Rushton impeller, power number of the super-hydrophobic Rushton impeller was decreased by 8.53%, which had a significant energy-saving effect.