Designation and evaluation of enclosed gravitational water vortex turbine (GWVT) at horizontal orientation for micro hydropower generation / Muhammad Qamaran Abdul Aziz

A sustainable electricity power supply is crucial, especially for a small population in a rural area. Micro hydropower generation in rural areas is important to ensure electricity can be provided, especially in off-grid areas. This study aims to predict power produced from conical gravitational water vortex turbine (GWVT) via horizontal orientation. Thus simulations were carried out before and after the actual turbine experiment to ensure the validity of the results produced for power output predictions through mathematical modelling. This study's conical GWVT was designed in a fully enclosed system with a conical turbine casing. During the simulation phase by using SOLIDWORKS Flow Simulation, two different turbine orientations were simulated, i.e. vertical and horizontal at different blade angles design (25°, 45°, 75°, 90°, and 120°), and with a different number of blades, i.e. 8, 12, and 18, while forces were harnessed as the selection criteria to find the optimum turbine setting. The optimized setting from the simulations was adapted for actual fabrication. The turbine underwent various flow rate tests, i.e. 0.0053 m3 /s, 0.006 m3 /s, 0.0063 m3 /s, and 0.00645 m3 /s, and loading conditions, i.e. 1kg increment until the shaft completely stop turning to obtain its performance curve. Then, validation of actual experimental results was done through simulation using MRF method in SOLIDWORKS Flow Simulation. The outcome of the actual turbine experiment was then modeled through multiple linear regression using the Minitab software. The simulation results showed that it was possible to run and produce force from horizontal conical GWVT designed in a fully enclosed system. It was found that vertical turbine orientation produced slightly higher force than horizontal orientation using runner blade of 90° angle and 12 blades where the distributed forces were 15.31 N and 14.12 N, respectively, at tangential (z-axis) direction. The maximum power produced was 69.39 W, while efficiency of the turbine was calculated at maximum 16.06% which was achieved at angular velocity of 12.71 rad/s and torque of 5.47 N.m. For validation of actual turbine experiment and simulation, results shown that the simulation can produce accurate torque predictions at higher angular velocity settings i.e. 15–30 rad/s within +1 N.m discrepancies from actual turbine results but under prediction occurs at low angular velocity settings i.e. 0-15 rad/s within -6.1 N.m discrepancies. The regression equation P=89.9+7.32X1+24.25X2-11.23X3 achieved R 2 of 55.36% and overall power output prediction accuracy of 73.43%. The results are helpful to predict the performance of conical GWVT, prior to actual implementation