This study explores the impact of various geometric modifications, including leading-edge openings, trailing- edge openings, and circular openings, on the performance of the H Darrieus hydrokinetic turbine. These modifications involved the removal of material from a symmetrical NACA0018 airfoil along its surface. The leading edge and trailing edge openings extended from the lower to the upper surface of the blade, while the circular opening was applied exclusively to the upper surface. Using the commercial software ANSYS® V22.2, the turbine was designed, discretized, and analyzed through computational fluid dynamics employing the Realizable K-e turbulence model. The primary output variable measured was torque, from which the power coefficient for each design modification was derived, allowing for the calculation of efficiency in each scenario. Notably, the configuration featuring the upper circular opening achieved the highest efficiency at 51.88% at a Tip Speed Ratio (TSR) of 2.0, a significant improvement over the standard case which had an efficiency of 45.16%. In contrast, the leading-edge and trailing-edge openings resulted in reduced efficiencies of 44.54% and 31.19%, respectively. The enhanced power coefficient of the H Darrieus hydrokinetic turbine with circular openings is attributed to the increased pressure difference generated between the upper and lower surfaces of the blade, surpassing the performance of the standard design.

Hydropower is an important source of energy in Latin America. Many countries in the region, including Brazil, Peru, Colombia, and Chile, rely heavily on hydropower plants to meet their energy needs. However, there are also challenges related to the use of hydropower in the region, such as the construction of dams that can have negative impacts on ecosystems and local communities. A new alternative is the production of energy through hydrokinetic turbines because they are a clean and renewable energy source that does not emit greenhouse gases. In addition, its production is predictable and can be generated in a variety of environments, from coasts to rivers and canals. Within the hydrokinetic turbines are the H-Darrieus turbines although they are still under development, they are seen as an important opportunity to diversify the energy matrix and reduce dependence on fossil fuels. The main purpose of this study is to determine and compare the efficiency of three Darrieus H-type vertical axis hydrokinetic turbines numerically. The turbines were configured with different solidities. The NACA 0018 profile was used for the turbine design. The study was carried out using the ANSYS® Fluent 2022R2 software, two-dimensional (2D) simulations set up constant operating conditions. Rotation speed variations have been set between 21 and 74 RPM with 10 rpm increments. Furthermore, the General Richardson extrapolation method is used for the analysis of mesh convergence, monitoring the turbine power coefficient as a convergence parameter. The numerical results show that the turbine H-Darrieus with a solidity of 1.0, a wider operating range, and lower power and torque coefficient. At low TRS, the largest solidity provided the best efficiency and the greatest self-starting capability, but it also had the smallest operating range

In industry, the search for reducing energy consumption directly impacts the manufacturing sectors due to the high power consumption required for their processes. Thus, studies on machining centers that identify factors impacting this demand, while maintaining the quality of the surface finish on...

This study presents a general 3 × 5 × 5 factorial experimental design to maximize the Power Coefficient (Cp) of an H-Darrieus hydrokinetic turbine equipped with external accessories. Five accessory configurations (standard, cycloidal, flat plate, curve, and blocking plate), three solidity levels, and five Tip-Speed Ratio (TSR) levels were evaluated as main factors under the hypothesis that these factors significantly influence Cp. The data analyzed were obtained from numerical simulations, and their processing was conducted using Analysis of Variance (ANOVA), linear regression models, and response surfaces in the software programs Minitab 21 and RStudio V4.4.2. ANOVA makes it possible to determine the statistical significance of the effect of each factor and their interactions on the obtained Cp, identifying the accessories, TSR, and solidity that have the greatest impact on turbine performance. The results indicate that the optimal configuration to maximize Cp includes the flat-plate accessory, a solidity of 1.0, and a TSR of 3.2. From the linear regression models, mathematical relationships describing the system’s behavior were established, while the response surface analysis identified optimal operating conditions. These findings provide an effective tool for optimizing H-Darrieus turbine designs, highlighting the positive impact of accessories on performance improvement.

The transition to sustainable energy systems requires the development of efficient hydrokinetic technologies to increase the reliability and competitiveness of renewable energy generation. Vertical-axis H-Darrieus turbines can improve their performance through impeller channels or external flow guidance devices that modify the local mass flow distribution around the rotor. This work introduces a systematic geometric optimization framework that quantitatively evaluates the combined effect of key channel design parameters on turbine performance by employing response surface methodology (RSM) to quantify the influence of two geometric parameters of an impeller channel—specifically, the deflection angle ($\beta$) and the channel length (H)—on the turbine power coefficient ($C_p$). This approach allows for the identification of nonlinear interactions between geometric variables, which have not been explicitly addressed in previous research on impeller channels in H-Darrieus turbines. An experimental design with thirteen treatments was implemented, and numerical simulations were performed using Computational Fluid Dynamics (CFD) in ANSYS FLUENT^®. Statistical analysis of the RSM model showed that both $\beta$ and H have significant effects ($p<0.05$) on turbine performance. The model predicted an optimal configuration with $\beta$ equal to 100° and H equal to 0.2 m, corresponding to the maximum Cp achieved. These findings confirm the potential of impulse channels to improve the aerodynamic efficiency of H-Darrieus turbines and establish a quantitative basis for design optimization in hydrokinetic applications.