Investigating the flow performance of Francis turbines from model to prototype is a complex but essential process for ensuring reliable and efficient turbine operation in hydropower plants. It ensures that Francis turbine designs operate efficiently under various operating conditions, extending from laboratory reduced-scale models to full-scale prototype installations. In this investigation, a Francis turbine model was tested under different operating conditions, and its properties were measured, including torque, hydraulic efficiency, power output, cavitation coefficient, rotational speed, flow rate, and pressure pulsations. The results of the Francis turbine model test indicate that it achieved the maximum torque with the designed discharge and designed head. The cavitation coefficient consistently remained higher than the critical cavitation coefficient. The initial cavitation bubbles were observed at 50% partial load but disappeared at full load. Pressure pulsations under different operating conditions showed the maximum peak-to-peak amplitude appearing at the turbine inlet domain and the minimum amplitude occurring at the draft tube elbow. A hill chart shows that the model’s best efficiency was 93.66%, and the estimated best efficiency of the prototype was 95.03% at the design head. The conclusions and methodology of this study can be generalized to other similar hydraulic turbines, especially prototype Francis turbines that lack experimental results.

Francis Turbines are designed to Extract hydraulic power as much as possible in hydro power plant stations. Performance analysis and selecting design of hydraulic turbines are two very essential aspects of any hydro power project which ensure the economical and efficient functioning of these hydro power plants.CFD simulation can provide us insight into field flow characteristics which will help us understand the design parameter and development of Francis turbine. The performance analyzed in different operating conditions with the help of numerical simulation and experimental testing. The various visualization techniques in numerically and Physically model testing for hydraulic performance with maximum-minimum and rated head and different flow rate analyses of the turbines are briefly discussed. These techniques can be provided efficiency and insight flow characteristics with different operating conditions of the Francis turbine. Efficiency is calculated 94% with Computational fluid dynamics simulation with an error of less than 0.7% compared with physical model testing. The numerically simulation and physical model testing are shown that feasibility for the optimal design of the hydraulic Francis turbine.

Sediment erosion of hydraulic turbines is a significant challenge in hydropower plants in mountainous regions like the European Alps, the Andes, and the Himalayan region. The erosive wear of Pelton runner buckets is influenced by a variety of factors, including the size, hardness, and concentration of silt particles; the velocity of the flow and impingement angle of the jet; the properties of the base material; and the operating hours of the turbine. This research aims to identify the locations most susceptible to erosion and to elucidate the mechanisms of erosion propagation in two distinct designs of Pelton runner buckets. The Pelton runner buckets were subjected to static condition tests with particle sizes of 500 microns and a concentration of 14,000 mg/L. The buckets were coated with four layers of paint, sequentially applied in red, yellow, green, and blue. The two Pelton buckets, $D_1$ and $D_2$, were evaluated for their erosion resistance properties. $D_2$ demonstrated superior erosion resistance, attributed to its geometrical features and material composition, lower erosion rates, less material loss, and improved surface integrity compared with D1. This difference is primarily attributed to factors such as the splitter’s thickness, the jet’s impact angle, the velocity at which particles strike, and the concentration of sand. $D_2$ exhibits a great performance in terms of erosion resistance among the two designs. This study reveals that the angle of jet impingement influences erosion progression and material loss, which is important to consider during a Pelton turbine’s design and operating conditions.

The transition toward renewable-dominated power systems is increasingly constrained by the shortage of flexible regulation resources. Hydropower, with its rapid response and strong load-adjustment capability, remains a cornerstone for enabling large-scale integration of intermittent wind and solar energy. Splitter-blade runners are widely employed in medium- and high-head conventional hydropower plants and pumped-storage stations due to their broad high-efficiency operating range and superior stability. In this study, based on a runner replacement project at an existing hydropower station, refined computational fluid dynamics (CFD) simulations were carried out to design a splitter-blade runner under strict dimensional constraints. The optimized runner expanded the unit’s stable operating range from 50–100% to 0–100% rated power, while also improving overall efficiency and reducing pressure pulsations. The optimized splitter-blade runner improved efficiency by 1–2%, reduced pressure pulsations in the draft tube by ≈25%, and decreased the runner radial force by ≈12% compared with the baseline configuration. Importantly, this work demonstrates for the first time that splitter-blade runners can be successfully applied at head ranges below 100 m, thereby extending their applicability beyond traditional limits. The results provide both theoretical and practical guidance for flexibility retrofits of existing Francis turbine units in China, offering a feasible pathway to support the adaptability of future renewable energy systems.

Pelton turbines, which are powered by high-pressure water, are often subject to erosion problems, especially in areas where sand or other hard particles are present along with the water. Numerical modeling was performed for the analysis, in which the VOF (Volume of Fluid) model was used to represent the interaction of two fluids (water and air), while the DPM (Discrete Phase Model) was applied to measure the particle motion, surface impact angle, velocity, and their effects. The turbine surface was modeled in a rotating physical state to obtain results closer to reality. The results showed that erosion is mostly concentrated on the blade edges, the central part, and the trailing edges. The particle impact angle, their density, and velocity have a direct impact on the severity of erosion. An increase in erosion was observed over time, confirming the decrease in efficiency and material loss. During the discussion, it was observed that specific materials and blade designs can reduce the severity of erosion. It was also concluded that numerical modeling provides an effective alternative for erosion prediction without practical experiments. The conclusion of this study is that the numerical study should be expanded in the future with different materials, surface coatings, and advanced blade geometries, in order to minimize erosion and improve the lifespan and efficiency of turbines. Furthermore, the incorporation of real-time monitoring systems and machine learning-based predictive models could lead to significant advances in the future.