Dynamics and Wear Analysis of Hydraulic Turbines in Solid-liquid Two-phase Flow

Abstract

To solve unstable operating and serious wearing of a hydraulic turbine in its overflow parts under solid-liquid two-phase flow, a particle model software and an inhomogeneous model in CFX are used to simulate the hydraulic turbine to understand the wearing of overflow parts and the external characteristics under the solid-liquid two-phase flow. Eleven different conditions at different densities and concentration have been calculated. The simulation results show that the volume distribution of solid particles is larger at the turn of the volute and nose end, resulting in the serious wear in this area. Due to uniform flow at the butterfly edge of volute under solid-liquid two-phase flow, the wear at the entrance of guide vane, the inlet of the blade and the outlet in the shroud is more serious than in other sections. Meanwhile, the collision between the solid phase particles and the overflow components is more intense under solid-liquid two-phase flow in the rotor which can lead to cavitation especially in the outlet and shroud of the blade. In addition, with the increase of density and concentration of solid particles the inlet and outlet pressure difference gradually rises, causing the efficiency loss of the hydraulic turbine.

Insightful Understanding of Shear-Assisted Supercritical CO2 Exfoliation for Fabricating Graphene Nanosheets through the Combination of Kinetics and Process Parameters

“…Besides, when the gap between the draft tube and the impeller was small enough, a strong shear force can be obtained. When an impeller was used in the solid–liquid phase, the impeller could make the flow in the draft tube flow upward, and the graphite flakes precipitated at the bottom could be carried to the inner of the draft tube, which was beneficial to the exfoliating process …”

“…When an impeller was used in the solid− liquid phase, the impeller could make the flow in the draft tube flow upward, and the graphite flakes precipitated at the bottom could be carried to the inner of the draft tube, which was beneficial to the exfoliating process. 46 In this study, two types of draft tubes with a 33 mm inner diameter were selected: one with long circular holes (1.5 mm width of the opening) and the other without holes. The results are presented in Table 2.…”

Analysis of Solid-Liquid Two-Phase Flow in the Area of Rotor and Tailpipe

“…Sha Yi Liu et al investigated the solid-liquid two-phase flow hydraulic transport characteristics of vortex pumps, and the results show that under the condition of certain particle concentration, the efficiency and head of the pump usually decrease with the increase of the particle size [19]. Weiguo Zhao conducted a study on the turbine performance and wear of a hydraulic turbine in solid-liquid two-phase flow, dynamics and wear, and the results showed that the distribution of solid particles is larger and wear is more severe at the turn and front end of the worm casing, and cavitation readily occurs at the blade outlet and the blade crown [20]. Sun Yuxiang et al analyzed the effect of particle motion on the flow of the slurry in the pipeline, and it was shown that the lower the degree of sphericity, the greater the number of collisions between the particles and the pipeline and the greater the energy loss is [21].…”

Numerical Simulation of Fine Particle Solid‐Liquid Two‐Phase Flow in a Centrifugal Pump

“…Particles collide with each other frequently, and the movement of particles is affected not only by the liquid phase in the pump, but also by the characteristics of particles. erefore, it is of great significance to study the influence of particle size and volume concentration on the flow performance of centrifugal pump [10][11][12][13].…”