Analysis of Pressure Distribution and Flow Patterns in Francis Turbine Runners Resulting from Reverse Engineering Using CFD

Abstract

The study tests how well a Francis turbine runner performs under hydraulic conditions by using reverse engineering methods together with steady-state computational fluid dynamics (CFD) testing. Researchers used 3D scanning to create runner geometry, which they turned into a digital model that they used for conducting numerical analysis. Six guide vane openings were tested using three different operating heads set at 60m, 100m, and 136m. The analysis studied different performance curves, hill-chart characteristics, pressure distribution patterns, and streamline flow patterns. The results showed that discharge and shaft power increased with guide vane opening for all operating heads, while efficiency increased only up to the best efficiency point and then decreased at larger openings. The tests showed that different guide vane openings produced different results because each head operated at its own peak efficiency zone. The hill chart identified a high-efficiency zone, while pressure contours and streamlines showed that medium guide vane openings produced more favorable flow behavior than larger openings. The plant data validation confirmed that the predicted power of 1076 kW matched the reference value of 1050 kW, which resulted in a 2.48% error.