Abstract
Geometrically, the single-blade centrifugal impeller, commonly used today as a sewage pump, is not axially symmetric. For this reason, the static pressure around the impeller fluctuates greatly when the impeller is rotating, and not only the radial thrust but also the axial thrust shows large fluctuations. Therefore, it is extremely important for the improvement of pump reliability to quantitatively grasp these fluctuating hydrodynamic forces. In this study, we investigated the unsteady hydrodynamic forces in a closed-type centrifugal pump with a single blade for different blade outlet angles using a numerical analysis that takes into account both experiment and the leakage flow. The results clearly showed the effect of the blade outlet angle on that act on the impeller. The root-mean-square value of the fluctuating component of the total radial thrust was roughly the same for whichever impeller at low flow rate, but at high flow rates, the value increased for impellers with larger blade outlet angles. Moreover, when the leakage flow rate increased with increasing static pressure around the impeller, such that the rear and front shroud parts were subject to high pressure, the absolute value of the axial thrust on both these parts increased.
Highlights
Because a sewage pump is used for the transfer of liquids containing foreign bodies, such as solid and fibrous material, it must be highly efficient and allow the easy passage of foreign bodies
The results showed that the errors in the flow rate, at the maximum efficiency point in the analysis results for the βb2 = 8 case, were 0.2% for the head, 0.3% for the shaft power, 0.7% for the root-mean-square value of the total radial thrust, and 4.1% for the time-averaged value of the total axial thrust
From the results of investigating the effect of the blade outlet angle on the fluctuating hydrodynamic forces in a closed-type centrifugal pump with a single blade, using both experiment and numerical analysis, we have found the following
Summary
Because a sewage pump is used for the transfer of liquids containing foreign bodies, such as solid and fibrous material, it must be highly efficient and allow the easy passage of foreign bodies. By performing a numerical analysis that takes into account the leakage flow on the rear surface of the rear and front shroud parts, we were able to demonstrate that did the radial thrust fluctuate with fluctuations in the static pressure distribution around the impeller and the axial thrust fluctuated greatly [14]. We implemented a numerical analysis that takes into account the leakage flow on the rear surface of the rear and front shroud parts of a closed-type single-blade centrifugal pump for different blade outlet angles. With a comparative investigation, we could clarify how the blade outlet angle affects both the radial and axial thrust in the closed-type single-blade centrifugal pump
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
