Browsing by Author "Faraji, Adam"

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Computational and experimental performance analysis of a runner for gravitational water vortex power plant
(NM-AIST, 2024-08) Faraji, Adam
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.
Exergy analysis and performance testing of a gravitational water vortex turbine runner for small hydropower plants: An Experimental Approach
(College of Natural and Applied Sciences, University of Dar es Salaam, 2024-10-02) Faraji, Adam; Jande, Yusufu; Kivevele, Thomas
Gravitational water vortex power plants (GWVPPs) have recently gained popularity due to their low initial investment, simple design, ease of maintenance, and low head utilization. However, the technology suffers from poor performance issues caused by the non-optimized parameters of its crucial components, such as the runner. In this study, the performance of a runner (16° blade-hub angle, six blades, and a curved blade profile) for a GWVPP was experimentally examined. The study also employed an exergy analysis. The experimental results revealed that the efficiency of the GWVPP system was in the range of 9.84% to 25.35%, the torque was in the range of 0.08 to 0.23 Nm, and the output power was in the range of 2.96 to 7.33 W. Furthermore, an exergy analysis of the system showed an exergy efficiency of 43.58%. Additionally, the error analysis of the GWVPP revealed ranges of 0.1 - 0.5 W for power, 0.01 - 0.03 Nm for torque, and 1.3–3.1% for efficiency, suggesting that the experimental setup and instrumentation of this study were reasonably accurate. Based on the results, the new vortex runner and GWVPP system are recommended for energy generation in low-head, low-flow small hydropower plants.
Performance analysis of a runner for gravitational water vortex power plant
(Wiley & Sons Ltd, 2022-02-14) Faraji, Adam; Jande, Yusufu; Kivevele, Thomas
Micro-hydropower can be used to meet the needs of both isolated and rural com munities for electricity. Due to its inexpensive initial investment, simple design, easy maintenance and low-head utilisation, the gravitational water vortex power plant (GWVPP) has recently piqued interest. The findings of numerical work employing a numerical simulation and analytical approach for the GWVPP are presented in this study. To understand the influence of each on the efficiency of GWVPP, four parameters (speed, hub-blade angle, number of blades and run ner profile) were explored. Design-Expert software was used to investigate the interplay of each parameter/factor in order to maximise the contribution of each. Design-Optimal Expert's (custom) design tool was used to construct twenty-four experimental runs. To calculate the system efficiency, these runs were simulated in commercial computational fluid dynamics (CFD) software called Ansys CFX. The numerical results were in good agreement with the experimental results, which yieldedR2 values of 0.9507 and0.9603 forflat andcurvedprofiles,respectively.Furthermore, the findings show that the chosen parameters have an impact on the GWVPP's efficiency via interaction as seen in response surface methodology (RSM). Furthermore, numerical analysis increased the curved blade profile runner's total efficiency by 3.65%. In compari son with the unoptimised scenarios, the efficiency of the flat runner profile increased by 1.69%.