| Summary: | 碩士 === 華梵大學 === 機電工程研究所 === 95 === In this study, flow fields of axial flow pumps with different rotating impeller hub designs and different number stator vanes are analyzed. A commercial finite volume code, STAR-CD, is utilized to simulate the flow fields under the impeller rotating speed of 7000 rpm. The governing equations for the flow fields are conservation of mass and momentum equations. For the turbulence calculations, a high Reynolds number k-ε turbulence model is used. Multiple rotating frames and steady interaction technique have been used to simulate the flow fields.
A total of four different pump designs are investigated in this study. The models’ variations include two different hub designs and two different numbers of stator guide vane. Model 1 has a cylindrical hub with 6 stator vanes. Model 2 uses the same hub as model 1 but possesses 12 stator vanes. Model 3 and model 4 have a cone shape hub. Model 3 has 6 stator vanes while model 4 has 12 stator vanes.
The results show that model 1 possesses the best efficiency and model 2 is the 2nd and model 4 is 3rd while model 3 is last without considering cavitation. Due to the fact that cavitation region of model 1 is significant, it may not be the best choice. If we compare the torque and thrust force, model 4 obtains a higher torque and thrust force than model 1, although model 4’s efficiency is not as good as model 1. Moreover, if we compare the effects of the number of stator vanes, we can see that models with 6 stator vanes have higher flow rates but smaller torque and thrust force than those models with 12 stator vanes. Thus, efficiency is not directed related with flow rate. In addition, models with 12 stator vanes have higher torque and thrust force.
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