Design and Optimization of Mixed Flow Pump Impeller Blades with Hydrostatic Loading and Varying Semi-Cone Angle

Abstract

Mixed Flow pumps are a combination of both axial and radial flow pumps. In present days they are having a wide range of applications. The impeller blade designing of mixed flow pump has always been a difficult task, the reason being it requires a lot of designing parameter to be considered for successful designing. When compared with radial and axial flow turbo-machines the mixed flow type of turbo-machines always get less importance for these complexities in their designing process. This complexity arises because of the complicated blade and geometry of fluid flow passage. Impeller is considered as one of the most important components in a mixed flow pump for the flow passage. The main motive behind the study of impeller blade design is to cite the reasons for the low hydraulic performance of the pump originally taken into consideration. When the pump is in functioning or operating condition, the rotation of the impeller provides with a geometric shape and the passage of flow gets distorted. It has been observed that all the available designs of the mixed flow pump, impeller blades are designed with a constant semi-cone angle, where as various data books for pump model test signify the fact that the semi-cone angle for these impeller blades can vary a specified range. So it is always an option to verify the fact that if variation of semi-cone angle in this specified range affects the designing parameters or not. From the literature survey it is found that various design methods such as Fourier expansion singularity method, free vortex method, mean stream line theory method, inverse time marching method, the pseudo-stream function method etc., adapted by various researchers, but the design methodology is always a tedious task.Here the authors have proposed the blade designs with a variation of semi-cone at hub.The concepts of Fluid Mechanics and Hydraulic Machines play a vital role in this designing process. Further taking the Hydraulic loading into consideration analysis is done to obtain the possible designs for the impeller blades. Finally optimization is carried out and the optimized design (blade with optimal geometry) is obtained with a varying semi-cone angle taking Hydraulic Loading into consideration.