STUDY OF THE SPATIAL FLOW IN THE FLOW PART OF THE HIGH-PRESSURE FRANCIS TURBINE

Анотація

The paper presents some results of a computational study of the spatial turbulent flow of a viscous fluid in the flow part of the high-pressure Francis turbine Fr500, made using the CFX-TASCflow application program package. To improve the energy performance at the preliminary design stage of the turbine, numerical flow simulations should be carried out. This CFD approach reduces costs and time in comparison with the experimental approach and makes it possible to improve and analyze turbine performance and its design before the model is manufactured. The computational complex of programs provides an opportunity to see the picture of pressure distribution, the field of velocity vectors and the movement of fluid particles for substantiation and analysis of results. Numerical modeling of the spatial flow in the flow part of the turbine was carried out to determine changes in the energy characteristics, therefore, the k-ε turbulence model was chosen. As a result of the calculation, the distribution of speeds and pressures in the various elements of the hydraulic turbine was determined at different openings of the guide vane. The analysis of energy losses in the flow part of a Francis turbine: a spiral case, a stator with flat rings, a guide vane, a runner and a draft tube on the optimal operating mode of the
hydraulic turbine, as well as an analysis of the effect of opening the guide vane on changes in energy losses in various elements of the flow parts . The results of the computational study confirm that the hydraulic efficiency of a hydraulic turbine largely depends on the losses in the guide vane and the runner, which means it is these elements that should be given the most attention, their design and coordination of the flow in them. The issue of increasing the energy performance of the flow parts of a high-pressure Francis turbine was also considered.