Numerical analysis of solid–liquidtwo-phase turbulent flow in Francis turbine runner with splitter bladesin sandy water

Abstract

As the key component of a hydroelectric power generation system, hydraulic turbine plays a decisive role in the overall performance of the system. There are many sandy rivers in the world, and turbines working in these rivers are seriously damaged. Therefore, the research of flow in sandy water has great theoretical significance and practical value. Based on the specific hydrological conditions of a hydropower station, the solid-liquid two-phase flow in the whole flow passage of a Francis turbine with splitter blades in sandy water was numerically studied. A geometric model of the whole flow passage of the Francis turbine was established on the basis of given design parameters. The solid-liquid two-phase turbulent flows in Francis turbine runner under three different loads were numerically analyzed by using this model. The three different loads are as follows: Condition 1: single unit with 1/4 load, Condition 2: single unit with 1/2 load, and Condition 3: single unit with full load. The distributions of pressure and sand concentration on the leading side and the suction side of the runner blades, as well as the velocity vector distribution of water and sand on the horizontal section of the runner, were obtained under different load conditions. Therefore, the damages to various flow passage components by sand can be qualitatively predicated under various conditions. To guarantee the safety and stability of the unit, the adverse conditions shall be avoided, which can provide certain reference for plant operation.

Numerical Study of Sediment Erosion Analysis in Francis Turbine

“…Generally, in the cavitating condition, water carries bubbles into the high regions of higher pressure, but in the case of cavitation-erosion, water, as well as sediment, carries the vapor bubbles into the high-pressure region [21]. For that reason, cavitation-erosion is more important than the normal cavitation condition.…”

“…Weili et al [20] investigated the cavitation characteristics due to the abrasion of the axial turbine in sand-laden water, and they found that cavitation was more likely to occur there than in clean water. On the other hand, Hong et al [21] numerically investigated solid-liquid flow behavior in the Francis turbine at different working load conditions. Rakibuzzaman et al [22] numerically and experimentally studied the cavitation erosion phenomena in a multistage centrifugal pump.…”

Research on the Influence of Solid Volume Fractions on Turbine Performance

“…This model has been used to simulate the solid-liquid twophase turbulent flow in the runner of Francis turbines used in Jinping II Hydropower Station on Yalong River in China, and has been proved reliable [18].…”