| dc.description.abstract | Energy generation through water is one of the most economic sources of power. On the other
hand, isolated and rural communities can both benefit from using micro-hydropower to power
their homes. The gravitational water vortex power plant (GWVPP) has recently attracted
interest due to its low initial investment, straightforward design, simple maintenance
requirements, and low head requirements. However, the technology suffers a low performance
caused by unoptimised parameters of its crucial components, such as the GWVPP runner. This
study presents the results of numerical simulation and experimental approaches for the
GWVPP runner. To understand how each factor affected the efficiency of GWVPP runner,
four parameters (hub-blade angle, speed, runner profile, and number of blades) were examined.
The (custom) design tool of Design-Optimal Expert was used to create twenty-four (24)
experimental runs. Commercial Computational Fluid Dynamics (CFD) software, specifically
Ansys CFX, was employed to simulate these runs and assess the system's efficiency. R2 values
of 0.9507 and 0.9603 for flat and curved profiles indicate a better model fitting to actual data.
Additionally, the numerical analysis led to a 3.65% improvement in the efficiency of the curved
blade profile runner, while the flat runner profile's efficiency increased by 1.69% compared to
non-optimized scenarios. The validation process revealed that the comparison between the
numerical investigation and experimental results demonstrated a promising agreement, further
supporting the accuracy of the numerical analysis. The experimental finding depicts that the
efficiency was 9.84 - 25.35%, torque was 0.08 – 0.23 Nm, and the output power was 2.96 –
7.33 W. Furthermore, the results portray the numerical efficiency to be slightly greater by
0.54% than the experimental efficiency, presumably because the frictional forces were not
incorporated in the numerical analysis. Additionally, the exergy analysis of the system revealed
a value of 43.58%. The power error range was between 0.1 and 0.5 W, with a low variation in
the data points. The torque error range was relatively lower than the power error range, ranging
from 0.01 to 0.03 Nm, and the torque measurements showed a low variation in the data points.
The efficiency error range was generally low, with most errors falling within the 1.3-3.1%
range. Therefore, the GWVPP runner efficiency can be improved significantly through
numerical analysis and experimental studies. Also, based on the above results, the GWVPP
runner and GWVPP system are recommended for energy generation in low-head and flowrate
water sources. | en_US |
