Savonius Hydrokinetic Turbine Research Articles

Design and Retrofitting of Irrigation Pumping System for the Middle Ogun Irrigation Project Using Hydrokinetic Technology

High cost of irrigation pumping by use of fossil fuel has negatively impacted irrigation efficiency on the Middle Ogun Irrigation scheme. Efficient irrigation pumping would improve agricultural productivity and food production on the irrigation scheme. Many attempts have been made by stakeholders to seek alternative energy sources for powering irrigation pumping. This study aimed at the design and retrofitting of the irrigation water pumping system on the Middle Ogun Irrigation scheme using hydrokinetic technology. Hydrological modelling of the catchment was carried out using MapWindow Soil and Water Assessment Tool to determine the annual gross and recoverable hydrokinetic potential of the water resource from the river. A Savonius hydrokinetic turbine system was developed and tested on the river. The mean voltage output at selected streamflow depths were determined to derive a power curve. Results showed that retrofitting the irrigation pumping system with an array of twenty units (20) of selected submersible irrigation pumps powered by twenty-two (22) units of an array of Savonius hydrokinetic turbines would satisfactorily deliver irrigation water into night storage and irrigate the pilot field of 100 ha of farmland on plot 2 and 5 on the scheme.

Effect of Semi-elliptical Outer Blade-surface on the Savonius Hydrokinetic Turbine Performance: A Numerical Investigation

Effect of Semi-elliptical Outer Blade-surface on the Savonius Hydrokinetic Turbine Performance: A Numerical Investigation

Enhancing hydrodynamic efficiency of Savonius hydrokinetic turbine through circular deflector flow augmentation

ABSTRACT The present numerical study employs a passive flow control augmentation mechanism to enhance the hydrodynamic performance of the Savonius hydrokinetic turbine. Two cylindrical deflectors guide the flow over the Savonius rotor blades. The effectiveness of placing the deflectors is examined by positioning them upstream of the returning and advancing blades. The Savonius hydrokinetic rotor’s efficiency is improved by incorporating Deflector1 to decrease the counteracting torque from the returning blade and Deflector2 to magnify the positive torque produced by the advancing blade. The study focuses on finding a suitable position ( L 1 ) and size ( d 1 ) of Deflector1 while keeping the size ( d 2 ) and position ( L 2 and ⍺) of Deflector2 fixed. The diameter of Deflector1 ( d 1 ) changes as d 1 / d =0 .15, 0.20, 0.25, 0.30, and 0.35 for each position, L 1 / d of 1.35, 1.65, 1.95, and 2.25. The study reports that the augmented Savonius turbine operates most efficiently at d 1 / d =0 .15, L 1 / d = 1.65, corresponding to a tip speed ratio of 0.9. The deflector-assisted Savonius hydrokinetic turbine enhances the power coefficient (C P ) by 54.1% in comparison to the ordinary Savonius rotor lacking deflectors. Further, utilizing cylindrical deflectors upstream of the Savonius hydrokinetic rotor improves the operating TSR range of the Savonius hydrokinetic turbine.

Performance enhancement of savonius hydrokinetic turbine using split airfoil blade: A numerical investigation

There is a concerted global effort to advance technology in the field of renewable energy sources due to the escalating energy crisis and escalating environmental pollution. One promising avenue for small-scale power generation is hydrokinetic technology. Among the various hydrokinetic turbines, the Savonius Hydrokinetic Turbine (SHT) stands out due to its specific advantages, but it has faced challenges in terms of performance. To address this, a novel blade design for the SHT has been developed, aiming to enhance its performance. This new turbine is referred to as the Split Airfoil Savonius Hydrokinetic Turbine (SASHT). To evaluate and compare the performance of both the conventional SHT and the newly developed SASHT, a Computational Fluid Dynamics (CFD) analysis has been conducted. This analysis encompasses a range of Tip Speed Ratios (TSR) from 0.7 to 1.2, with an inlet velocity of 0.8 m/s. The results reveal that the SASHT demonstrates a notable improvement, with a maximum Coefficient of Power that is 17% higher than that of the conventional semi-circular bladed SHT. This research offers valuable insights into the flow physics and performance parameters of these hydrokinetic turbines, showcasing the potential for more efficient and sustainable energy generation.

Numerical Study of Tandem Installation of Twin Savonius Hydrokinetic Turbines on PLTU Paiton Cooling Water Channel

Water energy is a renewable energy source that has enormous potential in Indonesia. In PLTU Paiton, there is a cooling water channel with a width of 15 m and a depth of 10 m with a water flow speed of 1 - 2.8 m/s. Of course, this is a source of energy that will be wasted if not utilised. This research proposes to exploit this potential energy source by installing twin Savonius hydrokinetic turbines arranged in tandem. This research uses numerical simulations to determine the optimal longitudinal distance between the twin turbines. The simulation configures two tandem turbines rotating in the same direction. The variations in this research are the distance between the two turbines. The turbine is simulated with a water flow speed of 2 m/s. The results obtained are that the greater the distance between the two tandem turbines, the better the performance of the two turbines. At the distance of T/D = 2.1, the front turbine and rear turbine influence each other, and distance of T/D = 70, the rear turbine does not affect the performance of the front turbine but the front turbine still affects the performance of the rear turbine.

Influence of Separation Gap on the Performance of Savonius Hydrokinetic Turbine

Influence of Separation Gap on the Performance of Savonius Hydrokinetic Turbine

Evaluation of the performance of the Savonius hydrokinetic turbines in the straight and curved channels using advanced machine learning methods

Evaluation of the performance of hydrokinetic turbines is an essential subject in the renewable energy field. In this regard, advanced machine learning methods including hybrid CatBoost and standalone Catboost and linear regression were used for the first time for the straight channel data and channel bend data. The hybrid models were developed using whale optimization (WO), grey wolf optimization (GWO), and Bayesian optimization (BO) algorithms. Sensitivity analysis was also conducted to find the most influential parameters in the best model. Results showed that the hybrid models can predict the goal parameters, including the coefficient of the power (CP), the maximum value of the coefficient of the power (CPmax), and the tip speed ratio corresponding to the Cpmax (TSRmax) better than the standalone models. Among the models, GWO-CB is the best model, even in the k-fold cross-validation scenario. The R2 value of the GWO-CB reached 0.97, 0.94, and 0.84 for the CP, CPmax, and TSRmax, respectively. Among the effective parameters, the lateral position of the returning blade deflector and the number of stages had the maximum and minimum effects on the best model, respectively. The effect of the position of the turbines in the channel bend, which was considered in this research for the first time, was significant in the models.

Effect of overlapping and space between stages of a three-bladed double-stage Savonius hydrokinetic turbine for low flow speed perennial river application

ABSTRACT Savonius-like hydrokinetic turbine (SAHT) in low-speed flow streams of perennial rivers is not much explored. In this paper, a triple-bladed double-stage SAHT is designed, and its performance is investigated for low flow speeds within 0.45–0.65 m/s under the effect of blade overlapping (within 10–20% in each stage), turbine diameter (within 208–234 mm), and without and with space between the stages (5.0 mm) at different operating speed ratios. Different combinations of design and operating input parameters are studied to obtain a reliable assessment of SAHT performance. After analyzing the results, the best conditions of input parameters and output performance parameters are reported in their nondimensional forms for future use of the obtained results. The torque produced by the turbine increased with the applied brake load, leading to its maximum value at the highest brake load 0.83 times the maximum load. The highest coefficient of performance is obtained as 0.086 at a space 0.25 times the maximum space (i.e. 20 mm), overlapping 15%, brake load 0.83 times the maximum load, tip speed ratio 0.276. And for this, the corresponding power 0.85 times the maximum power (i.e. 0.201 W) at free-stream flow speed of 0.85 times the maximum flow speed (i.e. 0.65 m/s) is obtained. The present turbine with space and overlapping exhibits better performance than some available SAHT designs of single/double stage, two-blade/multi-blade with/without overlap configurations. The novelty of the work is that an improved SAHT has been developed for low-flow speed perennial river applications in the band of low tip speed ratios by combining design conditions like double-stage, space between stages, and overlapping.

Hydrodynamic performance enhancement of Savonius hydrokinetic turbine using wedge-shaped triangular deflector in conjunction with circular deflector

Savonius hydrokinetic turbine is a viable technology for producing small-scale hydropower. The present numerical study proposed a novel deflector system to guide the incoming water stream effectively and to improve the hydrodynamic performance of the conventional Savonius turbine rotor. The combined deflector system comprises two deflectors: a newly proposed wedge-shaped triangular deflector and a circular cylindrical deflector. The triangular deflector is placed upstream of the returning blade, and the circular deflector is positioned upstream of the advancing blade. Different configurations of the proposed deflector system are obtained by varying the dimensions and location of the triangular deflector (deflector 1), while the diameter and location of the circular deflector (deflector 2) are fixed in all configurations. Without a deflector system, the Savonius rotor yields a maximum power coefficient equal to 0.248 at a tip speed ratio (TSR) of 0.7. The best configuration of the combined deflector system yields a maximum power coefficient of around 0.432 at a (TSR) value of 1.0. The deflector-augmented Savonius hydrokinetic rotor records a 73.7% increase in the maximum power coefficient (CPmax) compared to the conventional Savonius rotor. Further, the flow contours verify improved flow interaction with turbine blades and enhanced hydrodynamic performance.

Karakteristik Aliran Turbin Hidrokinetik Savonius Susunan Inward dan Outward Overlap dengan Dua Semicircular Blade-Flat Leading Edge

This current investigation was conducted to study the flow field through Savonius hydrokinetic turbine with flat blade leading edge. The influences of blade thickness, overlap, and freestream velocity were simulated using ANSYS FLUENT with k-w SST model. The results show that the flow structure changes with increasing turbine rotation flow complexity is formed at a larger rotation angle. Both inward and outward overlap lead to a more complex pattern of the flow. The coefficient of torque and power for thin blades is higher than for thicker turbine blades and its values increase with the increase in the freestream velocity.

Effects of submergence depth on the performance of the savonius hydrokinetic turbine near a free surface

The influence of the submergence depth ratio on the Savonius hydrokinetic turbine and flow characteristics is numerically studied under different tip speed ratios. The tip speed ratio TSR (Ratio of the flow speed to blade speed) changes from 0.4 to 1.2, and the submergence depth ratio H*(Ratio of the depth to the turbine diameter) ranging from 0.22 to 1.1. The main conclusions are: (1) When the submergence depth ratio increases from 0.22 to 0.66, the flow field structure gradually becomes regular, and the power coefficient keeps increasing. (2) When the submergence depth ratio reaches up to 0.88, the curve of the power coefficient is similar to that of H* = 1.1, which means the effect of free surface can be ignored when H*>0.88. (3) According to the pressure distribution around the turbine, the free surface will increase the pressure difference on the blade due to the surface tension and blockage effect, thereby influencing the rotation of the turbine. (4) As the TSR increase, the submergence depth ratios of 0.55 and 0.88 are regarded as two demarcation points of the average power coefficient.

Numerical investigation and experimental validation about negative overlap in Savonius hydrokinetic turbine

Numerical investigation and experimental validation about negative overlap in Savonius hydrokinetic turbine

One-way fluid structure interaction analysis of a static savonius hydrokinetic turbine under different velocity and surface roughness with different blade materials

Hydrokinetic turbines are prone to a harsh hydrodynamic environment with intricate vortical flows that elevate the probability of failure. The degradation of the blade surface caused by corrosion can impact the blade's hydrodynamic and the structural performance. This paper reports a one-way three-dimensional fluid-structure interaction simulation to analyse the performance of a static Savonius hydrokinetic turbine at varying rotor positions, with different surface roughness and water velocities, in terms of coefficients of static torque, static torque, stresses, and blade deformation. The simulations revealed that the optimum position for the highest coefficient of static torque was at 15° (Cst = 0.30) in reference to the water flow. Increasing the water velocity from 0.4 ms−1 to 0.84 ms−1 improved the turbine static torque due to an increase in the kinetic energy. However, the presence of surface roughness has deterioration effects on the static torque coefficient due to a delayed separation which causes a drag reduction. The simulation predicted no structural failure at 0.4 ms−1 and 0.84 ms−1, but varying materials exhibited varying maximum principal stress and deformation, highlighting the significance of the early development of materials selection process. The maximum von Mises stress and deformation was obtained when the turbine is resting at 45° for aluminium blade (σ = 1.05 MPa, ε = 5.6e−4 mm). The results of this study indicate suitable materials from a hydrodynamic and material perspectives for the construction of the Savonius hydrokinetic turbine, which can be implemented in the design process to potentially save cost and minimize turbine downtime.

Numerical Investigation of Savonius Hydrokinetic Turbine Having Novel Thick Blades.

Recently, hydrokinetic energy is playing an important role in the production of green energy. It boasts a minimal ecological footprint and holds significant promise for generating energy on a small scale. Savonius Hydrokinetic Turbine (SHKT) acquires the hydrokinetic energy and converts it into useful energy. It has some specific advantages over other hydrokinetic turbines. Two unique thick blade designs have been utilized to replace the traditional semi-circular blades of the Savonius hydrokinetic turbine, resulting in the creation of two novel variants known as SHKT Design-1 and SHKT Design-2. Numerical investigations are carried out to assess and contrast the performance of SHKT Design-1 and SHKT Design-2 with conventional SHKT, with inlet velocity 0.9 m/s at various tip speed ratios between 0.7 to 1.1. The current study demonstrates that, the performance of SHKT is greater compared to SHKT Design-1 and SHKT Design-2. Savonius hydrokinetic turbine has a 10.5% and 7.5% higher maximum coefficient of power compared to SHKT Design-1 and SHKT Design-2 respectively. The flow field generated about the SHKT, SHKT Design-1 and SHKT Design-2 are examined and deliberated upon to evaluate performance across different facets.

Investigations on the wave performance of Savonius turbine operating under initial phase-locked strategy

Savonius hydrokinetic turbines (SHTs), categorized as emerging cyclic-type wave energy converters (WECs), have demonstrated notable potential in achieving elevated energy conversion efficiency and consistent power output. This performance is particularly observed when operating under the initial phase-locked strategy (IPLS), marking a significant advancement in the realm of wave energy harvesting. However, a thorough exploration of the influences stemming from wave conditions and turbine design remains an area that warrants further investigation for advancing the performance of SHT-WECs under the proper operational strategy. This study undertakes an exhaustive analysis of geometric parameters, encompassing turbine diameter, blade number, and thickness. An experiment-validated numerical model based on the unsteady two-phase Reynolds-averaged Navier–Stokes equations is adopted in the research. Comprehensive investigations include analyses of flow fields around the turbine, pressure distributions on blade surfaces, and dynamic torque variations. These analyses serve to elucidate the variation rules of hydrodynamic characteristics and their influential mechanisms. The results highlight the notable impact of the proposed “relative-short wavelength impact” on the performance of SHT-WECs operating under IPLS conditions. Notably, no significant impact is observed when the relative wavelength exceeds 17. Optimal performance is achieved with the thinnest and two-bladed turbine configuration. Moreover, optimizing the turbine diameter significantly enhances SHT-WEC conversion efficiency, with the attained maximum value reaching approximately 18.6%. This study offers a concise guideline for designing turbine diameters in alignment with specific wave conditions.

A novel method of optimizing the Savonius hydrokinetic turbine blades using Bezier curve

Renewable electricity is increasingly gaining importance due to the quest for energy security and the harmful effects of fuel-based energy sources. Savonius hydrokinetic turbine (SHKT) can be a suitable means to provide electricity using rivers, canals, etc. Optimization of blade shape can play a vital role in enhancing the efficiency of SHKTs. A novel method to generate blade shapes has been proposed in this work using a Bezier curve with six control points. The method involves splitting a blade into two halves and optimizing those separately to simultaneously increase the pressure difference and the normal incoming velocity. The generated blade shapes were studied using a 3D transient computational model, which was validated with the obtained experimental results. Results showed that the blades generated using the proposed model show superior performance compared to conventional semicircular blades as well as the blades generated using four points Taguchi method. The most optimum blade profile achieved a maximum power coefficient of 0.21 at a tip speed ratio of 0.8. The efficiency of this new blade profile was found to be 16.7% higher compared to the semicircular blade, while the best blade using four points method was merely 2.1% more efficient than the semicircular blade.

Multi-objective optimization study of wave elimination and electricity generation performance of Savonius hydrokinetic turbine based on metamodel

The floating power generation and wave elimination system is getting more and more attention because of its multiple functions. The Savonius hydrokinetic turbine (SHT) can be used for wave elimination and power generation of offshore platforms due to its good self-start performance and simple structure. The wave elimination performance (WEP) and electricity generation performance (EGP) are closely related to the parameters of SHT, and these parameters are coupled with each other. Improving the performance of SHT under wave conditions and quickly analyzing the relationship between performance and parameters is a topic worth studying. In this paper, a multi-parameter multi-objective metamodel is established by CFD and RBFNN to meet the accuracy. And then coupled with NSGA –II algorithm to solve the Pareto front, quickly determining the optimized parameters of the SHT according to the decision criterion. Finally, a physical model is used for experimental verification, and the influence of each parameter on the performance is further analyzed. After optimization, the WEP is 0.3834 and the EGP is 0.2256. 55.7% and 28.6% improvement over the conventional structure, respectively. The metamodel is well representative within the optimization range. The optimized model still shows better performance in other conditions.

Performance investigation on blade arc angle and blade shape factor of a Savonius hydrokinetic turbine using artificial neural network

ABSTRACT Hydrokinetic turbines can generate electricity in remote rural locations using the kinetic energy of nearby rivers or canals. The Savonius hydrokinetic turbine (SHKT) is the easiest to design and manufacture. Optimization of blade shape factor (p/q) and blade arc angle (Φ) can contribute significantly to enhancing the efficiency of a turbine. The present work proposes a time-saving and reliable method to design an optimized SHKT by using a blend of experimentally validated 3D computational fluid dynamics (CFD) simulations and Artificial Neural Network (ANN). To optimize the turbine blade, the turbine performance needs to be analyzed for a number of values of blade parameters selected at very small intervals. Performing so many CFD simulations is a costly task. Application of an ANN tool trained using a smaller number of CFD results should significantly curtail the costs while maintaining reliability as well. The power coefficient (Cp) of SHKT was obtained using CFD simulations for some selected sets of Φ and p/q. These results were used to train the ANN by creating a parametric map between the input parameters viz. Φ, p/q, and the output parameter Cp. The trained ANN tool was further used to predict the turbine’s performance for sets of input parameters varying at very small intervals. The blade with p/q of 0.2 and Φ of 148° provides a maximum Cp of 0.209 at a TSR of 0.8. This optimal blade was 10.5% more efficient than the standard semicircular blade.

Performance assessment of savonius hydrokinetic turbine in a sharp 90° channel bend

Hydrokinetic technology is a new and competitive source of renewable energy in remote areas. Previous research on the impacts of the presence of this type of turbine have often been conducted in straight channels, and the effect of the presence of a turbine in a channel bend has not been studied yet. This study aims to investigate for the first time the effects of the siting of the Savonius hydrokinetic turbine in an open channel bend on the turbine performance. In addition, two rotation modes of the turbine, including clockwise and counter-clockwise have been investigated. Results showed that the siting of the turbine inside the bend increases the maximum power coefficient from 5 % to 30 % compared to the condition in which the turbine is located in the upstream straight channel. The maximum power coefficient occurred when the turbine was sited in section 90° for fully submerged conditions. In this section, the maximum power coefficient reaches 0.417 and 0.398 for the counter-clockwise and clockwise rotation modes, respectively. It was also observed that the values of the power coefficient in all sections for the counter-clockwise rotation mode of the turbine are higher than those for the clockwise rotation mode of the rotor.

Performance evaluation of the savonius hydrokinetic turbine using soft computing techniques

Savonius hydrokinetic turbine is a vertical axis turbine suitable for generating electrical power used in rivers and canals. The performance of the turbine is described in terms of power coefficient. The power coefficient (CP) depends on input variables such as aspect ratio, overlap ratio, blockage ratio, number of blades, blade arc angle, blade shape factor, twist angle, Reynolds number, and Tip Speed Ratio (TSR). In this study, different soft computing methods, namely CatBoost, Artificial Neural Network (ANN), Random Forests (RF), Multivariate Adaptive Regression Splines (MARS), Adaptive Neuro-Fuzzy Inference System (ANFIS), ANFIS-Genetic algorithm (ANFIS-GA), ANFIS-Slime Mold Algorithm (ANFIS-SMA), ANFIS-Marine Predators Algorithm (ANFIS-MPA) along with Linear Regression (LR) were used to predict the power coefficient of Savonius hydrokinetic turbines for the first time. In order to obtain appropriate data, experimental tests were conducted in an open water channel for different design configurations of Savonius turbines. Further, more data were collected from different references. These data were used for the training and testing process of the models. The precision of the methods was evaluated using multiple statistical indices. Three different training-testing scenarios were prepared to provide a reliable predictive model, and in all scenarios, the CatBoost method was superior. Sensitive analysis showed that aspect ratio is the most important design parameter among all effective parameters. As a result, the CatBoost is recommended to predict a Savonius hydrokinetic turbine's performance considering multi-input variables.