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Characteristics of a micro-hydro turbine
Journal of Renewable and Sustainable Energy
Abstract and Figures
Computational Fluid Dynamics, a crucial tool in exploring designs of hydraulic machinery, is used to evaluate the design of a non-uniform Archimedean spiral rotor. A transient simulation method is implemented using a frame of reference change between time-steps to capture the flow field correctly. The boundary conditions for this method are discussed and are validated with previously published experimental data using a flat plate propeller turbine. A spectral and temporal convergence study for the non-uniform Archimedean spiral rotor is performed to verify solution independence of mesh and time-step selection. Performance characteristics of the rotor are provided over a wide range of volumetric flow rates and rotation rates. The best hydraulic efficiency point is determined to be 72% for the presented rotor design and is compared with the performance of similar micro-hydro turbines. (C) 2014 AIP Publishing LLC.
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... Micro-hydro has much lesser impact on the environment compared to its large hydropower project counterparts because it does not require reservoir and most of the design could harness kinetic energy directly from running streams or rivers [4]. Often, low head micro-hydro projects end up being more expensive than large hydropower developments on a per megawatt basis [5]. However, for rural development or powering a smaller community, micro-hydro seems like an excellent renewable energy solution, especially with Archimedes screw turbines (AST) [6]. ...
... Attaching a generator allows this mechanical rotation to be used to produce electricity. [5] The actual performance of an AST depends on several parameters; rotational speed, angle of inclination, number of flights, geometry and performance, and gap, which are all related to each other. The selection of the optimum condition of these parameters are essential to the the turbine to operate and generate electricity. ...
This study aims to develop model to describe performance of small-scale Archimedes screw turbine (AST) operating in low velocity in-stream water. This study started off with conceptual designing based on literature review findings. Eventually, the small-scale prototype is then being built and tested in the laboratory. The experiment is set up to simulate the actual Sarawak river velocity to determine the relationship between key performance variables such as the inclination angle of AST and water flow velocity. The findings revealed that the 45-degree angle of inclination was the optimum angle of AST within the water velocity of 1.0 m/s until 1.5 m/s. At this angle, the highest revolution per minutes (RPM) generated by AST shaft was found to be 179.8, and the highest torque recorded was 0.9Nm. It was found that both angles of inclination and river water velocity are significant to RPM and torque generation (p< 0.05). The outcome of this study would be useful for designing a small-scale AST power generation system by utilising low flow river (velocity <1.5m/s) as a power source. For the future study, it is recommended to optimise the existing design of small-scale AST.
... In view of its high performance, it was also applied in ducted systems. For example, Rigling, Schleicher and co-workers evaluated numerically the efficiency of a non-uniform Archimedean spiral rotor in Ref. [13], finding the best hydraulic efficiency point equal to 72%. In both traditional and ducted conditions, the system requires a set of structures, this giving a significant environmental impact and making the use of such technology in remote areas inconvenient. ...
... Refs. [13,23]). In our case, we used CFD simulations to extrapolate the effect of the flow directly on the turbine, in terms of pressures and shear stresses and to evaluate the torque generated by the flow on the turbine. ...
The aim of designing a new hydrokinetic turbine simple, cheap, environmentally friendly and suitable for installation in remote areas is pursued by studying the efficiency of an Archimedes turbine that exploits the kinetic energy of a water stream rather than an upstream-downstream difference in water head. First, the efficiency of a hydrokinetic Archimedes turbine has been studied using laboratory experiments for low TSR regimes. Subsequently, numerical simulations have been run to evaluate the performance coefficient of the turbine only (without frictional losses or blockage augmentation), and to extend the TSR range. Numerical simulations have allowed to produce the efficiency curve of the hydrokinetic Archimedes turbine in both aligned and inclined configurations. The obtained maximum performance coefficients have been compared with those of other hydrokinetic turbines currently in use and inspected through a parametric analysis dedicated to explore the practical applications of the proposed turbine.
... The threaded turbine model is also intended for low elevation flow, screw turbine models are installed with a certain height so that the flow of water in the turbine will also form an elevation in accordance with the elevation of the turbine. The maximum efficiency is 72% and is not affected by the selected rotation rate; however, the rotation rate changes the flow rate at the best efficiency position (Schleicher et al., 2014). In Fig. 2 and 3, each shows a threaded turbine model (Rorres, 2000) and a screw model is displayed (Yulianto et al., 2017). ...
... A turbine for flat flow(EMRC, 2018;Schleicher et al., 2014) ...
... The steam pressure is the same in both shapes of the crosssection of the road blade, and the turbine reacts if the steam pressure in front of and behind the road blade is not the same or the steam pressure in front of the road blade is greater than behind the road blade. This also occurs due to the influence of the asymmetric cross-sectional shape of the road blade [5], [6], [7]. (2) Based on the direction of flow, they are classified into Axial Turbines, Turbines that are parallel to the direction of rotation of the turbine shaft. ...
In industry 5.0 availability of electricity plays an important role in the economic development of the community. In the villages on the slopes of the mountain there are still some villages that have not been connected to electricity so that the economic activity of the community is disrupted. Micro hydro electricity generation technology can be a solution to overcome the problem of the need for electrical energy in villages around the mountain slopes by utilizing differences in the height of the area and the flow rate of water from the river which has the potential to act as a turbine generator to be used as electricity to flow into the community to support community economic activities around the mountain slope. along with the existence of energy containers, the economy of the people on the slopes of the mountain will develop.
... Peningkatan kecepatan memberikan peningkatkan output daya turbin ketika geometri tertentu diterapkan. Pekerjaan telah dilakukan untuk menghasilkan turbin portabel yang dapat menghasilkan daya 500 W terus menerus [9][10][11][12][13][14]. Sebuah desain turbin berbasis baling-baling diperkenalkan oleh Schleicher et al. dan memperkenalkan nilai soliditas sudu turbin yang lebih tinggi dari pada yang digunakan dalam desain turbin hidrokinetik dan pasang surut. ...
The national electrification ratio is only 72.95%. As many as 27.05% of the territory in Indonesia has not been reached by electricity with various obstacles, one of which is because of the remote location so that access is difficult. One of the efforts to overcome the electricity problem is to take advantage of the potential energy sources around people's residences. One potential that might be used is a water energy source with low head and discharge. Ideally, this is done by using a generator system that uses a propeller type turbine. The difficulty of making propeller turbines is especially in the manufacture of housings and turbine blades. In this research, an attempt is made to simplify the turbine housing and turbine blades so that they are easy to manufacture. The design is made for Head (H) : 5 m Water flow (Q) : 0.11 m3/s Viscosity (ρ) : 998 kg/m3 Gravity (g) : 9.81 m/s2 Assumed hydraulic efficiency (ηh) : 0 ,80 Power (P) : 4,37 kW, Angle of attack (180o-β∞) 16o, Glide angle 55o, Thickness of inner blade(λ) 2,16o, Thickness of outer blade(δ) 2o. Simplification of the turbine housing is carried out by making the turbine housing from pipe iron and the simplification of the turbine blade is carried out by making turbine blades by eliminating the aerodynamic cross section of the blades, so that the blades can be made of steel plates without casting as is treated in aerodynamic sections. To see the effect of aerodynamic and non-aerodynamic cross-sectional shapes on efficiency, an efficiency test will be carried out.
... Peningkatan kecepatan memberikan peningkatkan output daya turbin ketika geometri tertentu diterapkan. Pekerjaan telah dilakukan untuk menghasilkan turbin portabel yang dapat menghasilkan daya 500 W terus menerus [9][10][11][12][13][14]. Sebuah desain turbin berbasis baling-baling diperkenalkan oleh Schleicher et al. dan memperkenalkan nilai soliditas sudu turbin yang lebih tinggi dari pada yang digunakan dalam desain turbin hidrokinetik dan pasang surut. ...
The national electrification ratio is only 72.95%. As many as 27.05% of the territory in Indonesia has not been reached by electricity with various obstacles, one of which is because of the remote location so that access is difficult. One of the efforts to overcome the electricity problem is to take advantage of the potential energy sources around people's residences. One potential that might be used is a water energy source with low head and discharge. Ideally, this is done by using a generator system that uses a propeller type turbine. The difficulty of making propeller turbines is especially in the manufacture of housings and turbine blades. In this research, an attempt is made to simplify the turbine housing and turbine blades so that they are easy to manufacture. The design is made for Head (H) : 5 m Water flow (Q) : 0.11 m3/s Viscosity (ρ) : 998 kg/m3 Gravity (g) : 9.81 m/s2 Assumed hydraulic efficiency (ηh) : 0 ,80 Power (P) : 4,37 kW, Angle of attack (180o-β∞) 16o, Glide angle 55o, Thickness of inner blade(λ) 2,16o, Thickness of outer blade(δ) 2o. Simplification of the turbine housing is carried out by making the turbine housing from pipe iron and the simplification of the turbine blade is carried out by making turbine blades by eliminating the aerodynamic cross section of the blades, so that the blades can be made of steel plates without casting as is treated in aerodynamic sections. To see the effect of aerodynamic and non-aerodynamic cross-sectional shapes on efficiency, an efficiency test will be carried out.
... In addition to theoretical models, studies based on Computational Fluid Dynamics (CFD) have also been considered. For example, the performance of a non-uniform Archimedean spiral rotor was numerically investigated for different values of volume flow rates and rotation speeds in (Schleicher et al., 2014), finding a maximum efficiency of 72%. Stergiopoulou and Kalkani (2015)studied screw performance with horizontal, vertical, and inclined axes using the Flow3D CFD software in (Stergiopoulou and Kalkani, 2015), but did not present any performance evaluation of the screw. ...
Archimedes Screw Turbines (ASTs) can become a popular device to generate electricity from hydraulic power at very low-head or nearly zero-head places. In this article, the performance of ASTs is numerically investigated using Computational Fluid Dynamics (CFD) to assess different screw rotation speeds, volume flow rates, and inclination angles. The numerical model is validated using experimental data, showing that the results computed using 5 million mesh cells lead to a relative error of 0.69% for a volume flow rate of 1.13 l/s, a rotation speed of 10 rad/s, and an inclination angle of 24.9ᵒ. Simulations are used to assess how mechanical torque and efficiency change with volume flow rate and inclination angle. Based on the results, CFD is a reliable tool for AST behavior study, predicting its performance, and visualizing pressure and velocity fields.
... Micro-hydro has a much lesser impact on the environment than its large hydropower project counterparts because it does not require a reservoir and most of the design could harness kinetic energy directly from running streams or rivers (Abbasi and Abbasi, 2011). Often, low head micro-hydro projects end up being more expensive than large hydropower developments on a per megawatt basis (Schleicher et al., 2014). However, for rural development or powering a smaller community, micro-hydro seems like an excellent renewable energy solution, especially with Archimedes screw turbines (AST) (Lyons and Lubitz, 2013). ...
In recent years, there has been a growth of interest in the development of micro-hydropower power generation, especially in the low head turbine. Low head turbine gained popularity due to its high efficiency, relatively low cost, ability to operate in low flow rate, and low environmental impact. In this aspect, the Archimedes Screw Turbine (AST) could be the primary key to electrifying the rural area in Sarawak, Malaysia, which is surrounded by rivers. This study starts with a conceptual design based on literature review findings. Eventually, the small-scale prototype is then being built and tested in the laboratory. The experiment is set up to simulate the actual Sarawak river velocity to determine the relationship between key performance variables such as the inclination angle of AST and water flow velocity. The findings revealed that the 45o angle of inclination was the optimum angle of AST within the water velocity of 1.0 m/s until 1.5 m/s. At this angle, the highest revolution per minute (RPM) generated by AST shaft was 179.8, and the highest torque recorded was 0.9Nm. The results were validated through statistical means. It was found that both angle of inclination and river water velocity are significant to RPM and torque generation (p< 0.05). Two statistical models were generated based on linear regression to explain the contribution of water velocity and angle of inclination as inputs to torque and RPM as outputs, with Pearson R² value of more than 60%. The maximum mechanical power generated is about 1.54kW, with the maximum efficiency of 94.6%. The outcome of this study would be useful for designing a small-scale AST power generation system by utilising a low flow river (velocity <1.5m/s) as a power source. This study would contribute to the existing knowledge stock of small-scale AST, primarily to operate in low flow velocity rivers. For the future study, it is recommended for conducting a pilot study to test the actual performance of AST in the Sarawak river or rivers with similar flow characteristics.
Hydropower is one of the reliable and cheap sources used for production of electricity. In recent years, distributed hydropower has got new attention due to the environmental issues. Production of electricity through hydropower plants is cheap but the initial cost is high by using old methods, and these are massive projects. To overcome these issues, low head turbines has got importance due to their small initial cost, easy to build and install. Sewage water can be one source of micro hydropower plants where low head Archimedes screw turbines can be installed to generate electricity. A single screw turbine installed in the sewage line can produce up to 2.0092 Watts of electric power. We want to find the angle where mechanical losses are minimum, and efficiency of AST is maximum. Also, our goal is to find the cheap, durable, and light weight material to make the AST which help us to improve its efficiency. The turbine is designed, flow simulation and AST blade material stress, strain & displacement is tested by using SOLID-WORKS. In theoretical results by set the turbine at 26º angle in the passage of flow water having head and discharge 0.38 m and 0.0012 m3/s, respectively. And AST has efficiency 34.97% with rotation speed 166 RPM and the torque 0.09 Nm. And pullies are used for power transmission between AST and generator
Hydrokinetic turbines are mechanisms designed for the purpose of utilizing the kinetic energy present in the movement of water bodies like rivers, tidal currents, or ocean currents, and transforming it into electrical power. These turbines function based on a principle akin to that of wind turbines; however, they are positioned underwater to harness the energy of the water flow. This study focuses on the fundamentals of hydrokinetic turbines and presents existing research. Additionally, simulations have been conducted to observe how the hydrokinetic turbine responds hydrodynamically inside a pipe. A three-bladed vertical-axis helical hydrokinetic turbine was installed within a circular conduit and subjected to analysis under varying flow conditions. The k-ω SST turbulence model was employed in the analyses. The results indicated that increasing the turbine's angular velocity initially raises the torque and the power coefficient until a peak is reached, after which the power coefficient decreases. The highest power coefficient was observed at a flow velocity of 2 m/s. Additionally, consistent with previous studies, the hydrokinetic turbine within the pipe surpassed the Betz limit.
Computational fluid dynamics simulations were conducted for two diffuser designs that were added to a pre-existing horizontal axis hydro-kinetic turbine design. The two diffuser designs investigated in the present study had the area ratio values of 1.36 and 2.01. Each design used a short axial length to satisfy system portability constraints. The turbine-diffuser systems steady-state performance characteristics were assessed numerically. A structured, hexahedral mesh was employed to discretize the equations governing the fluid motion. Turbulent flow structures were captured through the implementation of the k-ω Shear Stress Transport (SST) model. A 39.5% and 55.8% increase in output mechanical power was observed versus the un-augmented turbine performance. As the area ratio increases from 1.36 to 2.01, the total thrust experienced by the unit nearly doubles.
This research was carried out in order to develop a hydro turbine to be used for specific site of lower Head as run of river, which has head less than 1.2 meters. The new development of Very Low Head Turbine has been done in this research use the simple civil construction and resulting the economically viable. The recent development of computer-based tools with more efficient algorithms has allowed a substantial improvement in hydraulic turbine design. The definition of an initial geometry capable to assist certain characteristics of turbine performance is a first step for useful numerical turbine analysis. This paper presents an application of the minimum pressure coefficient and free vortex criterions for axial-flow hydraulic turbines cascade geometry design. The criterion was tested for VLH turbine and it was showed that it is suitable to define the initial geometry for machine design. The grid of the simulation domain was generated with GAMBIT grid software package and the results were obtained using the commercial package Navier Stokes 3-D FLUENT flow to analyze the fluid flow through blade runner. Using this procedure, a study was carried out on a small axial-flow turbine, specifically designed to operate in a Very Low Head. Finally, the results are evaluated to hydraulic efficiency prediction of blade runner turbines. The result of simulation has efficiency of 90% and produced the power of 2071 Watt at rotational speed 180 rpm and torque is 219.79 N-m, at the flow rate of 293.15 l/s. The prototype of turbine system was tested in Laboratory by using small channel system that we made it inside the laboratory. The tested result was obtained maximum efficiency of 90% and the power output simulation and experimental has the differential less than 5% at 200 rpm.
Results of a computational experiment designed to investigate the performance of different near-wall treatments in a single turbulence model with a common numerical method are reported. The complete fully elliptic, Reynolds-averaged Navier-Stokes equations have been solved using a low-Reynolds-number model, a new two-layer model, and a two-point wall-function method, in the k- epsilon turbulence model, for the boundary layer and wake of two axisymmetric bodies. These tests enable the evaluation of the performance of the different approaches in flows involving longitudinal and transverse surface curvatures, streamwise and normal pressure gradients, viscous-inviscid interaction, and separation. The two-layer approach has been found to be quite promising for such flows and can be extended to other complex flows.
The paper presents a general approach to constructing mean velocity profiles for compressible turbulent boundary layers with isothermal or adiabatic walls. The theory is based on a density-weighted transformation that allows the extension of the incompressible similarity laws of the wall to the compressible regions. The velocity profile family is compared to a range of experimental data, and excellent agreement is obtained. A self-consistent skin friction law, which satisfies the proposed velocity profile family, is derived and compared with the well-known Van Driest II theory for boundary layers in zero pressure gradient. The results are found to be at least as good as those obtained by using the Van Driest II transformation.
The Kolmogorov-Prandtl turbulence energy hypothesis is formulated in a way which is valid for the laminar sublayer as well as the fully turbulent region of a one-dimensional flow. The necessary constants are fitted to available experimental data. Numerical solutions are obtained for Couette flow with turbulence augmentation and pressure gradient and for turbulent duct flow. Reasonable agreement with available experimental data is obtained. Some new dimensionless groups are used and shown to be superior to the ones based on the friction velocity. The effects of turbulence augmentation and pressure gradient on the velocity and temperature distribution are studied. It is found that the solutions tend to approach solutions for limiting cases. The results are plotted in some figures in Section 5.
This paper describes the design of two different specific speed microhydro turbines operating at heads between 6 and 12m, at small scale and up to heads of 50m at larger scales. The features are specifically tailored for ease of manufacture and uniquely resistant to debris blockage. Test machines are described and test results given; hydraulic efficiencies of over 70% have been achieved in all test models despite the fact that the turbine blades are made from flat plate, specifically to simplify manufacture. Outline drawings are given with key dimensions for each reference model, along with the equations for scaling to arbitrary sizes. These turbines are the mixed- and radial-flow members of a family of turbines developed to cover the microhydro range from 2 to about 50m of head, which is below the range where Pelton wheels are applicable.