Effect of Blade Thickness on Internal Flow and Performance of a Plastic Centrifugal Pump

Blade thickness is an essential parameter of the impeller, which has significant effects on the pump performance. The plastic pump generally adopts thick blade due to low strength of plastic. The effects of blade thickness on the internal flow and performance of a plastic centrifugal pump were discussed based on the numerical methods. Two kinds of blade profile, the constant thickness blade (CTB) and the variable thickness blade (VTB), were investigated. The results indicated that, for the CTB, when the blade thickness was less than 6 mm, the pump performance did not change significantly. When the blade thickness exceeded 6 mm, the pump head and efficiency decreased rapidly. The pump head and efficiency of CTB 10 decreased by 42.2% and 30% compared with CTB 4, respectively. For the VTB, with blade thickness in a certain range (6 mm–14 mm), the pump performance changed slightly with the increased of trailing edge thickness. The minimum blade thickness of the plastic centrifugal pump should be 4 mm based on the finite element analysis. A variable thickness blade (VTB 4-8-4) with the maximum thickness located at 60% chord length was proposed to improve the pump performance, and its efficiency was 1.67% higher than that of the CTB 4 impeller.

DEVELOPMENT OF A GALVANIC COATING USING AN ADDITIVE RUBEAN ACID DERIVATIVE FOR THE PUMP HOUSING

The article presents the results of a study of the process of obtaining a shiny nickel coating on steel from sulfuric acid electrolyte in the presence of an organic brightening additive - a de-rivative of rubeanhydric acid - under different modes of electrolysis. The expediency of using a nickel coating for corrosion protection of the housing of a high-pressure centrifugal pump has been substantiated

Effect of outlet impeller diameter on performance prediction of centrifugal pump under single-phase and cavitation flow conditions

In this current study, the transient numerical calculations using CFD code are carried out under different outlet impeller diameters for the flow field within a centrifugal pump under single-phase and cavitation conditions. Both qualitative and quantitative analyses are carried out on all of these results in order to better understand the flow structure within a centrifugal pump. Also, the investigations using different outlet impeller diameters configurations relating to the static pressure, velocity magnitude, vapour volume fraction variations, as well as pressure fluctuations in both time and frequency domain at the impeller and volute of the pump are analysed. Velocity and static pressure variations of the pump under different outlet impeller diameters range (200, 210 and 220 mm) are investigated. Reliable model is developed and validated, at various pump operating conditions, to analyse the characteristics of pressure fluctuations in both time and frequency domain. Cavitation occurrence, under different outlet impeller diameters and flow rates, are detected and correlated, using a CFD model (volume fraction distributions). Based on the developed model’s findings, at the set operating conditions ranges, the distribution and impact (cavitation and head-wises) of both the pressure and velocity are analysed. The average pressure fluctuation in the volute for do = 210 mm is higher than for do = 200 mm by about 6.74%, also the maximum pressure fluctuation for do = 220 mm is higher than for do = 210 mm by around 7.4%. Furthermore, the maximum pressure fluctuation in the impeller for do = 210 mm is higher than for do = 200 mm by 12.48%, also for do = 220 mm is higher than for do = 210 mm by 10.8%. The developed CFD models are proved valuable tools in identifying and optimizing the pump performance and characterization. The head for when do = 220 mm is higher than for when do = 200 mm under both single-phase and cavitation conditions by around 14.13% and 14.69%. The maximum pressure fluctuation for do = 200 mm is lower than for do = 210 mm by 41.58%. Furthermore, the maximum pressure fluctuation at the impeller for do = 220 mm is higher than the two models. There is a small clearance between the impeller and the volute for this model, leading to the pressure fluctuation amplitudes being higher than the other above models.

Influence of grooved volute casing parameters on pressure pulsation and erosion wear characteristics in a centrifugal pump

Previous work has shown that performance and internal flow characteristics of a centrifugal pump can be significantly improved with grooved volute casing (GVC). However, it has been found that the selection of the design parameters of the groove structure also has a direct impact on the performance output, internal flow pressure pulsation and erosion wear characteristics of the overflow components of centrifugal pump, so it is necessary to further analyze the design rules of the groove structure parameters. In this study, we first investigated the influence of the number of grooves on the head, efficiency and unsteady pressure pulsation characteristics of the internal flow field of the centrifugal pump, and on this basis, the correlation between different particle parameters and the erosion wear of key overflow components under the conditions of solid–liquid two-phase flow were also studied, and the erosion wear characteristics of the inner wall of the volute casing of centrifugal pump with GVC and original volute casing (OVC) structures were compared. This research leads to the conclusion that when the number of grooves is 3, the groove structure has the least influence on the performance of the centrifugal pump, and the overall change of the performance curve is more stable. Additionally, the pressure pulsation at each monitoring point of the GVC under the same flow condition is smaller, and when the number of grooves increases, the pressure pulsation amplitude also decreases. When the number of grooves is 3, the GVC shows a more significant flow improvement effect under all flow conditions. Based on the improvement of the groove structure on the flow stability, the particle motion behavior can be affected at the same time, so that the pump with GVC can mitigate the erosion wear of the inner wall of the volute casing under the solid–liquid two-phase flow conditions, which improves the critical performance and service life of the key overflow components of the pump.