Effect of blade tip cutting angle on energy conversion mechanism of side channel pumps

Abstract

Typical industrial blade side channel pumps with tip cuts have been used for many years because the blade profile has significant effect on the performance of the pump. To investigate the effect of the tip cutting angle on the energy conversion mechanism of the pump, the original and the industrial blades with different tip cutting angles were studied in detail. A comprehensive analysis revealed that the cutting tip enhances the hydraulic performance of the side channel pump, especially when the angle is equal to 20°. The act of cutting the tip reduces the intersection of exchanged inflow and outflow between the impeller and side channel, especially at the outer radius, and eliminates the secondary flow at the corner. Furthermore, the application of the new Ω vortex identification method characterizes the dynamic vortex structures in three directions: axial, longitudinal, and radial. Based on the Galilean invariance of the vorticity, this paper operates coordinate transformation and uses the dimension reduction method to simplify the complex 3D (3 dimensional) vortex into 2D (2 dimensional) vortex intensity on specific research surfaces. By comparing each type of vortex, it can be established that the total vortex in the tip cutting scheme is more than the original scheme. This is because the cutting tip will produce extra space for vortex formation. Thus, the cutting tip schemes lead to a higher longitudinal vortex and lower axial vortex, thereby increasing the dynamic vortex and decreasing of the unfavorable vortex is the main reason for better performance. While the radial vortex seems equivalent, the tip cutting will increase this kind of vortex in the outlet region but decrease it in the inlet region as above. This work helps to understand the mechanism of energy conversion of side channel pumps and serves as a guide for further research in fluid engineering with strong swirling flows.

Numerical Investigation of Impeller Parameters on the Performance and Internal Flow Characteristics in Regenerative Flow Pumps

“…As can be seen from the figure 10, when the flow rate is 160L/h, the efficiency of model #2.2, model #2.4 and model #2.5 is higher than that of model #2.3, and the efficient working region will not only shift towards large flow, but also towards small flow. From the above analysis, it is concluded that the impeller height has two effects on the performance of RFP: (1) In order to ensure high head and high efficiency of RFP at rated flow rate, there is an optimal value of impeller height. ( 2) As the height of the impeller is greater than the optimal value, the head of the RFP will gradually be the same, and the efficiency curve turn to be much slower.…”

“…In recent years, relevant scholars have carried out a series of theoretical, experimental and numerical simulation studies on the structure improvement of blade and flow channel, unsteady flow inside RFP, and cavitation of RFP. Chen et al [1] investigated the impact of tip cutting angle on the energy exchange mechanism of a side channel pump, and discovered that utilizing the proper tip cutting angle structure can enhance the hydraulic performance of the pump. Notably, a tip cutting angle of 20° was found to significantly improve pump efficiency.…”

Transient vortical structure evolution under part-load condition in a high-power double-suction centrifugal pump based on Liutex method

“…Chen et. Al [11] applied Galilean Invariance in analyzing vortices in a side channel pump, and they presented the influence of radial vortices and axial vortices.…”