No abstract

Due to the serious abrasion caused by the existence of solid phase in slurry, the slurry pumps usually adopt thick impeller blades to prolong its service life. In this paper, the influence of the blade thickness on the transient characteristics, the vibration, and the solid–liquid two-phase flow in a ceramic centrifugal pump with annular volute was investigated by the numerical method. And the experimental test was also conducted for computational fluid dynamics validation. The static pressure, the velocity, the force, and the solid fraction within the impeller passage and the volute casing have been discussed in detail. The results show that the influence of the blade thickness variation on the pressure fluctuation intensity is larger at the impeller inlet than that at the impeller exit and is larger at the pressure sides than that at the suction sides. The pressure fluctuation intensity decreases at the regions close to the volute tongue with the increase in the blade thickness. However, it increases at the regions, which are away from the volute tongue as the blade thickness increases. Moreover, the torque on the impeller, the radial force, and the axial force decreases with the increase in the blade thickness. Meanwhile, increasing the blade thickness will disperse the solid fraction at the impeller back shroud and make the regions with high solid fraction on pressure sides offset towards the impeller exit with a larger blade thickness, thus prolonging the service life of the impeller. However, the best efficiency point offsets to a low flow rate condition. The results are expected to pave the way for further optimization of impeller blade profile.

The annular volute is typically used in a slurry pump to reduce the collisions between solid particles and the volute tongue and to achieve a better resistance to blocking. However, only limited studies regarding annular volutes are available, and there is no systematic design method for annular volutes. In this study, the influence of volute casing cross-sectional flow area on the hydraulic loss, pressure pulsations, and radial force under varying working conditions in a centrifugal ceramic pump are discussed in detail. Experimental tests were conducted to validate the numerical results. The results indicated that, when the volute casing flow area increases, the hydraulic performance decreases marginally under the rated working conditions, but increases at the off-design points, specifically under large flow condition. However, the volute casing with a larger flow area has a wider high-efficiency region. In addition, the increase in the volute casing flow area will decrease the pressure pulsations in the volute, regardless of the working condition, and decrease the radial force on the shaft, therefore, providing an improved pump operational stability. It is anticipated that this study will be of benefit during the design of annular volutes. which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

The impeller blades of ceramic slurry pumps are usually very thick for the purpose of prolonging the service life. In this paper, numerical simulations and wear test were conducted to investigate the influence of blade thickness on the solid–liquid two-phase flow and impeller wear in a ceramic centrifugal slurry pump. The wear test was conducted for CFD validation. The numerical results show that the incident angles of solid particles increase with increasing blade thickness, which results in larger wrap angles of the solid particle trajectories. The increasing wrap angles of the solid particle trajectories offset the region that the collisions between the blade pressure side and the solid particles side take place towards the impeller exit and lead to more impacts between the solid particles and the blade suction side. The numerical results are in good accordance with the wear pattern of the tested impellers, which demonstrates that the numerical method adopted in this paper is predictable in the abrasion of the impeller of a ceramic centrifugal slurry pump. The experimental results show that an increase in the blade thickness alleviates the abrasion of the leading edges and the pressure side of the impeller blades; however, it also aggravates the abrasion of the blade suction side and decreases the pump performance.