Helical Turbine Research Articles

Numerical and structural investigation of flow past a helical axis wind turbine

The present work is about designing a helical axis wind Turbine and testing its performance of both numerical and static structural analysis. NACA 0018 symmetric aerofoil is used as a turbine blade to modelling the vertical 3 bladed axis wind turbine rotor is tilted to an angle of 60 degrees, so as to get better performance of turbine. This paper deals, Numerical investigation of Helical Axis Wind Turbine (HAWT) with three blades has been carried out by means of both the numerical simulation and static structural analysis. The turbine performance can be observed by the span wise pressure distribution and velocity distribution, stress distribution and also observed that HAWT generated a power, which is an average power output incremental of 6.75 percent than precedes.

Performance Testing of a Helical Savonius Turbine with 3D Analysis

Performance Testing of a Helical Savonius Turbine with 3D Analysis

Field Tests on Model Efficiency of Twin Vertical Axis Helical Hydrokinetic Turbines

Field Tests on Model Efficiency of Twin Vertical Axis Helical Hydrokinetic Turbines

Pengaruh Jumlah dan Rasio Sudut Lengkung Sudu Terhadap Unjuk Kerja Turbin Angin Savonius Heliks

The helical Savonius is a vertical wind turbine that can utilize wind energy to become a renewable energy source. This study aims to determine the effect of the number of blades and the ratio of blade bends on the performance of the Savonius helical wind turbine. The research was conducted through experimentation using variations in the number of blades 2 and 3 blades. Variation of blade bending ratio H / L = 6/10, 7/10 and 8/10 and variations in wind speed (4.0), (5.2), (6.4) and (7.4) m / s. The turbine performance analysis is reviewed based on the shaft rotation (RPM) of the turbine and the output voltage (volts) generated by the generator connected to the turbine shaft. The results showed that the wind speed, the number of blades, and the blending ratio of the blades affect the performance of the Savonius helical wind turbine. The results of the maximum wind turbine performance test at a variation of 3 blades, a ratio of 6/10, and a wind speed of 7.4 m / s, produce a shaft rotation value of 472.9 rpm and a generator output voltage value of 5.51 volts.
 Keywords: Helical Savonius, number and ratio blade bend, wind speed, performance

A brief review on the Gorlov helical turbine and its possible impact on power generation in India

This article reviews the various technologies in crossflow hydro turbines and the viability of installing Gorlov helical turbine in possible potential sites. The article also shares insight into the small hydro project and its current situation in India. Various approaches in simulation for the cross-flow turbine are also evaluated. Also, various design approaches to Gorlov helical turbine are outlined with simulation. Much care is taken to introduce various experimental data regarding the output characteristics of the Gorlov helical turbine.

Helical vortices and wind turbine aerodynamics

All rotating blades shed helical vortices which have a significant effect on the velocity over the blades and the forces acting on them. Nevertheless, knowledge of vortex behavior is not used in blade element theory (BET), the most common method to calculate the thrust produced by propellers and the power by wind turbines. Helical vortices of constant pitch and radius are also of fundamental interest as one of only three geometries that do not deform under their “self-induced” motion. This aspect of vortex theory is reviewed historically and the relationship with the forces acting on submerged bodies briefly reviewed. The development of helical vortex theory (HVT) in the 20th century is then described. It is shown that HVT allows BET to be used for a number of important problems that cannot be analyzed by current versions of the theory.

Performance Improvement in a Helical Savonius Wind Rotor

Above all vertical axis wind turbines, for their lower cost and independent on wind direction, Savonius rotor takes the advantage to be more suitable for some implementation. Thus, many investigations have been carried out to improve its efficiency. This study emphasizes on the effect of the overlap distance and the blade shape on a helical Savonius wind turbine performance. Assessment methods based on the flow field characterizations, the variation of torque and power coefficient are performed. Thus, transient simulations using the SST k–ω turbulence model are carried out. The numerical model is validated using wind tunnel tests. Results indicate that the non-overlapped helical Savonius rotor highlights higher maximum power coefficient of 0.124 at a tip speed ratio of 0.73 over rotors with overlap distance of 10 mm, 15 mm and 20 mm, respectively. In addition, the delta-bladed rotor improves the performance of the helical Savonius rotor by 14.51%. With the novel blade shape, the maximum power coefficient reaches a value of 0.142 at a tip speed ratio of 0.78. The obtained results present an interesting data that could provide the aerodynamic characteristics of the airflow for the designers and engineers to enhance the efficiency of the helical Savonius turbine.

Performance improvement of a novel combined water turbine

Nowadays, industrials and researchers are looking for renewable energy resources due to the increase of energy demand. Recently, the ability of combined turbines in harnessing energy from water current has increased their renewed interest. However, there still exist a big knowledge gap to select the optimal design of these turbines. In this paper, systematic studies of stand-alone helical Savonius and delta bladed Darrieus turbines were carried out using experimental methods as a precursor to analyze their roles in hybrid configuration. By varying the attachment angle, two hybrid configurations were tested experimentally. Using the optimal attachment angle, six hybrid configurations were investigated numerically based on the commercial software ANSYS FLUENT 17.0. From one configuration to another, only the design of the Savonius turbine was changed. The maximum power coefficient is found to be equal to 0.191 at tip-speed ratio of 0.63 using a helical bladed Savonius turbine with twist angle of 90°. However, the maximum power coefficient reaches 0.232 using a delta bladed Savonius turbine with the same twist angle. This optimization of the novel combined water turbine could be a solution to enhance the generated power.

Simulation studies to analyze the static mechanical properties of helical Savonius vertical axis wind turbine blade

The focus of this study is to analyze the static mechanical properties of the helical Savonius vertical axis wind turbine blade. Commercial finite element code ANSYS is used to perform the static structural analysis. The helical Savonius wind turbine blade is tested by force varying from 15 N to 25 N representing the wind conditions ranging from 5 m/s to 11 m/s. The properties namely, maximum principal stress, equivalent (von-misses) stress, shear stress, maximum shear stress, equivalent elastic strain, and total deformation are analysed. The various static mechanical properties are observed to be the maximum for wind load of 15 N. The outer edges of the helical Savonius vertical axis wind turbine blade is observed to have the maximum total deformation values and the prolonged use of the helical Savonius wind turbine blade will lead to damage along the outer edges of the turbine blade leading to failure of the wind turbine blade.

CFD for Helical Type Vertical Axis Wind Turbine

Vertical axis wind turbines are most effective for home energy generation especially in urban environments. Wind energy creates a stand-alone energy source that is relied on any place. The main criteria for this work is the design of micro wind turbines for all kinds of applications. Design of Twisted Blade Micro-Wind Turbine system is accomplished using computer aided design with Computational Fluid Dynamics (CFD). The flow characteristics in the wind turbine blade were analyzed by varying its twist ratio. The wind turbines with vertical axis utilize the wind from any direction with no yaw mechanism. The risk of blade ejection besides catching wind from all the directions is avoided by using the helical tye vertical axis wind turbine.

Additive Manufacturing of a Gorlov Helical Type Vertical Axis Wind Turbine

In this work, a Gorlov helical type Vertical Axis Wind turbine (VAWT) model is designed and manufactured by using one of the additive manufacturing techniques called Fused Deposition Modelling (FDM) through a 3D Printer. The VAWT was made by interpretation of the wind conditions and by selecting of the suitable Airfoil profile for the blades of the turbine based on the DMS analysis (Q-Blade is an open source software which is particularly used in designing of wind turbine blades). The CAD modelling is done on SOLIDWORKS 2017 and later converted in to a Stereolithography (STL) format file which is compatible with the 3D Printing software called CURA by Ultimaker. All the parts were manufactured on the 3D Printer and assembled together and coupled with the suitable generator for the generation of Power. This VAWT is more suitable for urban areas and can generate more power even at the lower wind speeds unlike the Horizontal Axis Wind Turbines (HAWT) which require open lands for their efficient working.

Experimental and numerical study on the performance and flow pattern of different Savonius hydrokinetic turbines with varying duct angle

In this study, three different types of Savonius rotors viz. Savonius hydrokinetic turbine (SHKT), modified Savonius hydrokinetic turbine (MSHKT) and helical Savonius hydrokinetic turbine (HSHKT) are compared based on the performance. The analysis is done experimentally as well as numerically, where experimental domain ceases. Performance of rotors is also evaluated with and without applying duct as an augmentation technique in the flow channel. Experimentally, MSHKT and HSHKT produce 2.74% and 9.04% more energy than SHKT for 1 ± 0.2 m/s. Uncertainties in TSR, Cp and Ct of rotor are 3.05%, 4.39% and 5.35% for the experiment. It is found that HSHKT has better performance than others. Whereas, with duct, performance of HSHKT improves 48.08% more energy than SHKT. The insight of the hydrodynamic behavior considering wake formation, flow separation and vortex formation of the stream flow surrounding to the rotor is also explained using velocity contour, velocity vector and pressure plot. Inlet velocity of 1 ± 0.2 m/s increases by 27.5%, 28%, 29%, 32% and 34%, respectively, for duct angle 20°, 23°, 26°, 29° and 32°. Simultaneously, low-pressure zone increases which leads to extend the formation of the vortex far from rotor and helps to generate higher Cp for HSHKT as 28.63%, 16.16%, 43.01%, 50.13% and 82.32%, respectively.

Numerical and experimental study of a helical Savonius wind turbine and a comparison with a two-stage Savonius turbine

In this paper, the aerodynamic performance of a helical Savonius rotor model with 180° twisted blades is investigated numerically and experimentally. It is also performed a comparison of results with a two-stage Savonius with similar parameters. The experimental study is conducted in the aerodynamic tunnel Prof. Debi Pada Sadhu at the Fluid Mechanics Laboratory of UFRGS. Numerical simulations are performed using the Finite Volumes Method performed by the solution of the Reynolds Averaged Navier-Stokes (RANS) using the k-ω SST turbulence model. The static torque, dynamic torque and power coefficients are compared. Results show that the turbine has a positive static torque coefficient for any studied rotor angles. The dynamic torque coefficient of the turbine shows less torque variation along each rotation in comparison with a two-stage turbine, reaching the maximum value for a tip speed ratio (λ) of 0.2 for the experimental and numerical cases. The helical turbine, despite having a more complex manufacturing process than the two-stage turbine, presents stable torque and higher power coefficient. The maximum power coefficient of the rotor is obtained for λ of 0.65 for both cases. The numerical simulations and the experimental results present differences between 2.34% and 12.5% in CT and CP values.

THE EFFECT OF BLADE NUMBER AND WATER VELOCITY TOWARD THE PERFORMANCE OF HELIKS GORLOV TURBINE

This study was aimed at determining the influence of the number of blades and water velocity on the performance of vertical axis water turbine type Helical Gorlov. The method used was an experimental method. The descriptive analysis method was also used to analyze the data. The data obtained were in the form of variations of blades number and water velocity. The variations in the number of blades used were 2 blades, 3 blades, and 4 blades. While water velocity variations used were 0.81 m / s, 0.94 m / s, 1.08 m / s, and 1.18 m / s. The parameters were used to measure the amount of current and voltage produced by the multimeter and the number of rotations per minute (rpm) of the turbine produced by the tachometer. The results show that the number of blades and water velocity affected the performance of the Gorlov helical water turbine. The most optimal Gorlov helical turbine based on the results of research with the highest power coefficient (Cp) value is a turbine with 2 blades at a water velocity of 0.94 m/s which produces a Cp value of 0.00376 and a TSR value of 1.35.PENGARUH JUMLAH SUDU DAN KECEPATAN AIR TERHADAP KINERJA TURBIN AIR SUMBU VERTIKAL TIPE HELIKS GORLOVPenelitian ini bertujuan untuk pengaruh jumlah sudu dan kecepatan air terhadap kinerja turbin air sumbu vertikal tipe Heliks Gorlov. Metode yang digunakan dalam penelitian ini adalah eksperimen. Penelitian ini menggunakan analisis deskriptif.Data yang duperoleh berupa variasi jumlah sudu dan variasi kecepatan air. Variasi jumlah sudu yang digunakan adalah 2 sudu, 3 sudu, dan 4 sudu. Variasi kecepatan air yang digunakan yaitu 0,81 m/s, 0,94 m/s, 1,08 m/s, dan 1,18 m/s. Parameter dalam penelitian ini yang digunakan untuk menentukan kinerja adalah mengukur besarnya arus dan tegangan yang dihasilkan multimeter dan banyaknya rotasi per menit (rpm) dari turbin yang dihasilkan tachometer.Hasil penelitian menunjukkan bahwa jumlah sudu dan kecepatan air mempengaruhi kinerja turbin air heliks gorlov. Kedua, kecepatan air mempengaruhi kinerja turbin air heliks gorlov.Turbin heliks Gorlov paling optimal berdasarkan hasil penelitian dengan nilai koefisien daya (Cp) tertinggi yaitu turbin dengan 2 sudu pada kecepatan air 0,94 m/s yang menghasilkan nilai Cp sebesar 0,00376 dan nilai TSR 1,35.

Performance study of a Helical Savonius hydrokinetic turbine with a new deflector system design

The use of renewable energy sources has becoming a necessity to generate electricity. Helical Savonius rotors have been preferred for small-scale hydropower generation. Numerous studies were carried out to improve the performance of the Helical Savonius rotor which has not been fully explored. In this paper, an experimental study was carried out to evaluate the performance of a Helical Savonius water rotor in an irrigation channel. In order to enhance the performance of the studied water rotor, a new deflector system design was proposed. Different configurations of the proposed deflector system were tested numerically using the commercial software ANSYS FLUENT 17.0. Without a deflector system, the maximum power coefficient is found to be equal to 0.125 at tip-speed ratio of 0.7. Using the optimal configuration of the new deflector system, the maximum power coefficient reaches 0.14. The utilization of this new design system is predicted to contribute towards a more efficient use of flows in rivers and channels for electricity production in rural areas.

Design, simulation and performance evaluation of vertical axis helical wind turbine

This report is all about the design, simulation, fabrication, and performance evaluation of the VAHWT. The experimental data obtained via testing and data from CFD approach are used for performance evaluation. From the data obtained experimentally, the VAHWT so fabricated has been found to operate at the low cut-in speed of 3.18 m/s and maximum power output has been found to be 2.656 watts at the wind speed of 8 m/s. The maximum rpm of the rotor blade is recorded to be 722.2 rpm at the velocity of 11.53 m/s signifying its potentiality of wind power production. Besides, the data so obtained from both the process when analyzed through graph plots, has shown the similar nature slope wise. This simply signifies the generation of satisfactory data via experiment. In addition, the mechanical losses has shown difference between the experimental and data obtained via CFD approach. At the end, when applying CFD approach for evaluation of maximum efficient turbine varying the aspect ratio, has shown the turbine with aspect ratio of 0.6531 to be the most efficient with performance coefficient of 36.396%. However due to limitation in RPM and Test rig, the rotor blade with aspect ratio of 0.6956 was fabricated and used for evaluation experimentally. The data so obtained from both the process were concluded to be relevant to each other. Thus, the detail study on this project has led to the need and opportunity of VAHWT to be further researched and can be developed as a good source of energy producing system. It can also be economical method of power extraction from wind in the countries like Nepal with growing urbanization.

Power-tracking control for cross-flow turbines

For economic reasons, above a certain water speed, it is desirable for current turbines to maintain a constant power output. This requires a control strategy to shed power. Here, such a strategy is evaluated through simulation and laboratory experiment for a helically bladed turbine with four blades and a straight-bladed turbine with two blades. These are contrasting cases because hydrodynamic torque produced by the straight-bladed turbine has a substantially more azimuthal phase variability than the helically bladed turbine. For practical implementation, a control algorithm is desired that requires only a time-average characteristic performance curve and estimates of angular velocity and control torque. Additionally, the transition between power maximizing and power tracking regimes should be smooth and automatic. The controller can be further constrained to only apply a resistive torque to the turbine. A control strategy satisfying these constraints is shown experimentally to achieve these objectives for both types of turbines at a variety of power set points. The power-tracking error (<3%) is primarily at the blade passage frequency for the straight-bladed turbine and at the rate of turbine rotation for the helical turbine. While partially a consequence of how the generator drive is tuned, comparison to simulation indicates that perfect power-tracking is not generally possible even under ideal conditions for a fixed-pitch, cross-flow turbine using purely resistive torque control.

Experimental and Numerical Evaluations of Helical Turbine Performance and Proposal for Theoretical Model

Experimental and Numerical Evaluations of Helical Turbine Performance and Proposal for Theoretical Model

Numerical investigation of the effects of immersion on the efficiency of a tidal helical turbine

In the current study, a two-phase simulation of a tidal helical turbine was performed that contrasts with previous studies in two ways. First, the current research simulated the turbine in different states of immersion in water, whereas previous studies simulated turbines mostly in single-phase conditions and full immersion in water. Second, the present study used a horizontal-axis turbine, whereas previous research employed a vertical-axis helical turbine or Darrius turbine. In this study, a simulation was conducted using the volume of fluid method in ANSYS Fluent 18. Results indicated that the complete immersion of the turbine in water generated a high torque, thereby reducing the efficiency of the device. To determine the conditions with the highest efficiency, immersion rates of 100%, 75%, 50%, and 25% in water were examined, and a configuration with best power coefficient ( C p = 0.175 in TSR = 0.47) was found in 25% immersion. In immersion rate of 25%, resistant pressure on blades was minimum.

Numerical evaluation of helical hydrokinetic turbines with different solidities under different flow conditions

In the present study, the effect of the turbine solidity on the performance of helical cross-flow hydrokinetic turbines is numerically investigated under different flow conditions. Four turbines, with different solidities of 0.15, 0.2, 0.25 and 0.3, were investigated in five dissimilar flow conditions with Froude numbers of 0.0714, 0.143, 0.214, 0.286 and 0.357. The devices employed in the analyses were three-bladed with the diameter of 1 m and length of 1.5 m. They were positioned horizontally in a rectangular-shaped channel with a perpendicular alignment to the flow direction. Symmetrical NACA0018 hydrofoils, which are twisted with an angle of 120°, were used in the blade design. The investigation results have shown that the turbines with the solidity values 0.15 and 0.2 are more efficient than the other two cases. Considering all five flow conditions, the models have displayed the worst performance at a tip speed ratio of 4.0.