scholarly journals Numerical study of savonius water turbine performance by adding deflector to advancing blade side

2018 ◽  
Author(s):  
Priyo Agus Setiawan ◽  
Anda Iviana Juniani ◽  
Adi Wirawan Husodo
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Numerical Study ◽  
Renewable Energy Sources ◽  
Power Coefficient ◽  
Turbine Performance ◽  
Water Turbine ◽  
Unsteady Rans ◽  
Deflector Plate ◽  
Coarse To Fine

As one of the best renewable energy sources, hydropower becomes more predictable sourcecompared to wind energy and Savonius which its performance does not contingent to fluid flowdirection. In this present, computational Fluid Dynamics acomplished by Finite Volume Methodand unsteady RANS equation were applied to analyze the numerical simulation. The presentstudy investigated the performance of Savonius Turbine by adding deflector plate installed toadvancing blade side at 5, 10, 15, 30 and 45 of deflector angles in the direction of the fluid flow.The viscous turbulence model used realizable k-epsilon (RKE) and its descritization usedsecond order upwind. The type of mesh was made from coarse to fine meshing with 8 (eight)types of meshing and the grid independency of the numerical simulation had been validated bythe publish experimental data at TSR of 1,078. Grid independency occured at meshing G withthe error lower than 5 % compared to published experimental data. The result of this studyshows that the performance of Savonius turbine increased by adding deflector in advancingblade side with the maximum torque and power coefficient at 30 of deflector angle.

scholarly journals Experimental and Numerical Study of Water Entry Supercavity Influenced by Turbulent Drag-Reducing Additives

2014 ◽  
Vol 6 ◽  
pp. 280643 ◽  
Author(s):  
Chen-Xing Jiang ◽  
Feng-Chen Li
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
High Speed ◽  
Numerical Study ◽  
Ccd Camera ◽  
Water Entry ◽  
Multiphase Model ◽  
Turbulent Drag ◽  
Unsteady Rans ◽  
Simulation Results

The configurational and dynamic characteristics of water entry supercavities influenced by turbulent drag-reducing additives were studied through supercavitating projectile approach, experimentally and numerically. The projectile was projected vertically into water and aqueous solution of CTAC with weight concentrations of 100, 500, and 1000 ppm, respectively, using a pneumatic nail gun. The trajectories of the projectile and the supercavity configuration were recorded by a high-speed CCD camera. Besides, water entry supercavities in water and CTAC solution were numerically simulated based on unsteady RANS scheme, together with application of VOF multiphase model. The Cross viscosity model was adopted to represent the fluid property of CTAC solution. It was obtained that the numerical simulation results are in consistence with experimental data. Numerical and experimental results all show that the length and diameter of supercavity in drag-reducing solution are larger than those in water, and the drag coefficient is smaller than that in water; the maintaining time of supercavity is longer in solution as well. The surface tension plays an important role in maintaining the cavity. Turbulent drag-reducing additives have the potential in enhancement of supercavitation and drag reduction.

Numerical Analysis of Blockage Ratio Effect on a Portable Hydrokinetic Turbine

2016 ◽  
Author(s):  
Cosan Daskiran ◽  
Jacob Riglin ◽  
Alparslan Oztekin
Keyword(s):  
Free Stream ◽  
Numerical Study ◽  
Three Dimensional ◽  
Turbine Rotor ◽  
Power Coefficient ◽  
Stream Velocity ◽  
Blockage Ratio ◽  
Ratio Effect ◽  
Turbine Performance ◽  
Hydrokinetic Turbine

Three-dimensional steady state Computational Fluid Dynamics (CFD) analyses were performed for a pre-designed micro-hydrokinetic turbine to investigate the blockage ratio effect on turbine performance. Simulations were conducted using a physical turbine rotor geometry rather than low fidelity, simplified actuator disk or actuator lines. The two-equation k-ω Shear Stress Transport (SST) turbulence model was employed to predict turbulence in the flow field. The turbine performance at the best efficiency point was studied for blockage ratios of 0.49, 0.70 and 0.98 for three different free stream velocities of 2.0 m/s, 2.25 m/s and 2.5 m/s. Distinct blockage ratio results at a free stream velocity of 2.25 were compared to a previous numerical study incorporating the same rotor geometry within an infinite flowing medium. The pressure gradient between turbine upstream and turbine downstream for blocked channel flows elevated the turbine performance. The increment in blockage ratio from 0.03 to 0.98 enhanced power coefficient from 0.437 to 2.254 and increased power generation from 0.56 kW to 2.86 kW for the present study.

Experimental and Numerical Study of the Response of an Axial Compressor to Distorted Inlet Flow

1988 ◽  
Vol 110 (4) ◽  
pp. 355-360 ◽  
Author(s):  
G. Billet ◽  
J. Huard ◽  
P. Chevalier ◽  
P. Laval
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Numerical Study ◽  
Axial Compressor ◽  
Numerical Approach ◽  
Compressor Blade ◽  
Numerical Results ◽  
Test Stand ◽  
Viscous Effects ◽  
Inlet Flow

A model representing the response of fixed or rotating axial compressor blade-rows is coupled to a 3-D numerical simulation of the flow outside the blade rows. The code can be used to study nonuniform compressible 3-D flows through turbomachines. The fluid is assumed to be inviscid in the space outside the rows, while the viscous effects are taken into account inside. Numerical results are compared with experimental data obtained on a test stand with steady distorted inflow. This comparison shows that this numerical approach is capable of predicting the response of the compressor. This work is part of a larger project aimed at predicting the response of a compressor to a nonuniform inlet flow that is periodic in time, or fully unsteady.

Performance Analysis of Multi-Sectional Cycloidal Hydrokinetic Turbines

2021 ◽  
Author(s):  
Ang Li ◽  
Yijie Wang ◽  
Jun Chen ◽  
Greg Jensen ◽  
Haiyan Zhang
Keyword(s):  
Fluid Dynamic ◽  
Power Coefficient ◽  
Cfd Simulations ◽  
Hydrokinetic Turbines ◽  
Turbine Efficiency ◽  
Reliable Source ◽  
Sliding Interfaces ◽  
Water Turbine ◽  
Unsteady Rans ◽  
The One

Abstract Hydrokinetic power is the most efficient and reliable source of renewable energy and it has been utilized to produce power for centuries. The cycloidal water turbine is a subset of the H-bar type Darrieus turbines that are designed to actively controls the pitch angle of blades to improve turbine efficiency. However, the traditional cycloidal turbine has some shortcomings. For example, the torque and power coefficient vary significantly as the turbine rotates, which means the produced power is not uniform in one revolution. The associated hydrodynamic load will lead to fatigue of the turbine structure that will shorten the turbine lifespan. To solve this problem, a concept of the multi-sectional cycloidal water turbine is proposed. In the present study, computational fluid dynamic (CFD) simulations are applied to investigate the performance of the multi-sectional cycloidal turbine. A cycloidal turbine with three identical sections is designed. Each section consists of three blades and NACA0021 is chosen as the hydrofoil. Structured mesh with sliding interfaces is generated and arbitrary Mesh Interface (AMI) technique is employed. Unsteady RANS simulations with SST k–ω model are conducted to compute the flow field and torque generated by the turbine, and then power coefficient is computed. The results demonstrates that the three-section turbine has uniform performance in one revolution. At the design condition, the power coefficients of the one-section turbine and the three-section turbine are similar; when the TSR is much larger or less than the desired value, the three-section turbine has better performance.

Experimental and Numerical Investigations of Aerodynamic Behavior of a Three-Stage HP-Turbine at Different Operating Conditions

2010 ◽  
Author(s):  
S. A. Abdelfattah ◽  
M. T. Schobeiri
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
High Pressure ◽  
Operating Conditions ◽  
Numerical Investigations ◽  
Turbine Performance ◽  
Speed Range ◽  
Three Stages

This paper describes experimental and numerical investigations of a three-stage high pressure research turbine which incorporates fully 3-D bowed blades at various operating conditions. Experimental data were obtained using interstage aerodynamic measurements at three measurement stations, namely, downstream of the first rotor row, the second stator row and the second rotor row. Measurements were conducted through the use of five-hole probes traversed in both circumferential and radial directions to create a measurement window. Aerodynamics measurements were carried out within a rotational speed range of 1800 to 2800 RPM. Numerical simulation of the aforementioned turbine was performed through the use of a commercial computational fluid dynamics code. A detailed mesh of the three-stages was created and used to simulate the corresponding operating conditions and a comparison was made between experimentally and numerically determined aerodynamics and turbine performance.

Combined Experimental and Numerical Study for Multiple Microchannel Heat Transfer System

2010 ◽  
Author(s):  
Jingru Zhang ◽  
Yogesh Jaluria ◽  
Tiantian Zhang ◽  
Li Jia
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Steady State ◽  
Numerical Model ◽  
Initial Conditions ◽  
Numerical Study ◽  
Numerical Models ◽  
Three Dimensional ◽  
Variation Versus ◽  
Heat Transfer System

Multiple microchannel heat sinks for potential use for electronic chip cooling are studied experimentally and numerically to characterize their thermal performance. The numerical simulation is driven by experimental data, which are obtained concurrently, to obtain realistic, accurate and validated numerical models. The ultimate goal is to design and optimize thermal systems. The experimental setup was established and liquid flow in the multiple microchannels was studied under different flow rates and heat influx. The temperature variation versus time was recorded by thermocouples, from which the time needed to reach steady state was determined. Temperature variations under steady state conditions were compared with three-dimensional steady state numerical simulation for the same boundary and initial conditions. The experimental data served as input parameters for the validation of the numerical model. In case of discrepancy, the numerical model was improved. A fairly good agreement between the experimental and simulation results was obtained. The numerical model also served to provide input that could be employed to improve and modify the experimental arrangement.

scholarly journals Experimental Study of Darrieus-Savonius Water Turbine with Deflector: Effect of Deflector on the Performance

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Kaprawi Sahim ◽  
Kadafi Ihtisan ◽  
Dyos Santoso ◽  
Riman Sipahutar
Keyword(s):  
Experimental Study ◽  
Aspect Ratio ◽  
Performance Characteristics ◽  
Power Coefficient ◽  
Irrigation Canal ◽  
Savonius Rotor ◽  
Water Turbine ◽  
Darrieus Rotor ◽  
Deflector Plate

The reverse force on the returning blade of a water turbine can be reduced by setting a deflector on the returning blade side of a rotor. The deflector configuration can also concentrate the flow which passes through the rotor so that the torque and the power of turbine can be considerably increased. The placing of Savonius in Darrieus rotor is carried out by setting the Savonius bucket in Darrieus rotor at the same axis. The combination of these rotors is also called a Darrieus-Savonius turbine. This rotor can improve torque of turbine. Experiments are conducted in an irrigation canal to find the performance characteristics of presence of deflector and Savonius rotor in Darrieus-Savonius turbine. Results conclude that the single deflector plate placed on returning blade side increases the torque and power coefficient. The presence of Savonius rotor increases the torque at a lower speed, but the power coefficient decreases. The torque and power coefficient characteristics depend on the aspect ratio of Savonius rotor.

scholarly journals Performance Improvement of a Drag Hydrokinetic Turbine

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 273
Author(s):  
Mabrouk Mosbahi ◽  
Mariem Lajnef ◽  
Mouna Derbel ◽  
Bouzid Mosbahi ◽  
Costanza Aricò ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Rural Areas ◽  
Numerical Study ◽  
Renewable Energy Sources ◽  
Electricity Production ◽  
Power Coefficient ◽  
Design System ◽  
Sea Waves ◽  
Local Fauna ◽  
Savonius Rotor

Hydropower is at present in many locations, among all the other possible renewable energy sources, the best one for net cost per unit power. In contrast to traditional installation, based on water storage in artificial basins, free flow river turbines also provide a very low environmental impact due to their negligible effect on solid transport. Among them, kinetic turbines with vertical axis are very inexpensive and have almost zero impact on fish and local fauna. In application to tidal waves and sea waves, where vertically averaged velocities have alternate direction, a Savonius rotor also has the advantage of being productive during the whole time cycle. In this work, the effect of an upstream deflector system mounted upstream of a twisted Savonius rotor inside a channel has been investigated through numerical simulations and experimental tests. Numerical simulations were carried on using the ANSYS FLUENT 17.0 software. Based on this numerical study, it is shown that the proposed deflector system has improved the power coefficient of the Savonius rotor by 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.

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