Numerical Simulation On Internal Solid-liquid Two-Phase Flow In Francis Turbine With Long And Short Blades

The water turbine is a core component of the hydropower station and plays a decisive rolein the operation of the hydropower station. The traditional water turbine model test and fieldtest of the prototype unit is an important water turbine research means to researchers for a longtime. But the model test requires long time and much money. Because the turbulent flow is verycomplex in the water turbine, it is quite difficult that analyzing the internal flow field of thewater turbine by purely theoretical analysis method. Therefore, it is an important method todesign high-performance water turbine that using modern computational fluid dynamics (CFD)methods and high-performance computers to obtain accurate details of the water turbine’sflowing characteristic. It effectively combines the advantages of model tests and puretheoretical analysis, shortens the design period and reduces R&D expenses of the water turbine.Therefore, the CFD technology is widely used as a new water turbine′s design and researchmethod.The subject is about numerical simulation of full flow passage of a Francis turbine withlong and short blades in clear water and solid-liquid two-phase by CFD. According to thedistribution of pressure and velocity and particle volume concentration, the flow characteristicsof the flow passage components of the water turbine under different operating conditions canbe predicted. The cost and time of the model test can be reduced. The important information forthe model change of the turbine can be provided.Specific researches as follows:1. According to the actual hydraulic design parameters of the prototype turbineparameters, build the3D geometry model of a full flow passage of a Francis turbine was, whichconsist of spiral case, water guide, runner and draft tube.2. Import the3D model into the Gambit software, mesh the flow passage and specify thezone type and boundary type.3. Numerically calculate the water turbine’s flowing in clean water in conditions of smallflow, high flow and the optimal condition by Fluent.4. Numerically calculate the turbine’s flowing in other conditions. Such as, large particlevolume concentration and large particle diameter and the large flow condition in wet season;medium particle concentration and medium particle diameter and optimal condition in the levelperiod; small particle concentration and small particle diameter and small flow condition in dryseason. Through the comparative analysis of the calculated results, the law of silt abrasion andcavitation damage of the Francis turbine with long and short blades was obtained.