Performance Optimization for Cycloidal Hydrokinetic Turbine With Augmentation Duct for Harvesting Riverine Energy

2021 ◽  
Author(s):  
Yijie Wang ◽  
Ang Li ◽  
Greg Jensen ◽  
Jun Chen ◽  
Haiyan Zhang
Keyword(s):  
Flow Velocity ◽  
Performance Optimization ◽  
Power Efficiency ◽  
Fluid Dynamic ◽  
Ocean Energy ◽  
Hydro Turbine ◽  
Seasonal Flow ◽  
Hydrokinetic Turbine ◽  
Extracted Power ◽  
Horizontal Axis Turbine

Abstract With the increased demand for developing renewable energy, hydro energy has attracted more attention since it is reliable and easy to acquire. In this area, the cycloidal turbine has been recently studied and applied to ocean energy for its stable and efficient output. Compared to the ordinary vertical/horizontal axis turbine with fixed pitch angle blades (e.g., Darrieus turbine), the cycloidal turbine can maximize the extracted power efficiency by keeping the optimized angle of attack for the blades. Meanwhile, the cycloidal turbine provides a potential solution to solve the problems of self-starting and seasonal flow variations. Introducing an augmentation duct is considered as a method to further increase the incoming flow velocity of the turbine. Inspired by the design of the wind tunnel, a convergent-divergent design of the augmentation duct is developed. One is noted that the dimensions of the augmentation duct are essential to the performance of the duct. In this study, a convergent-divergent augmentation duct is developed based on a 3-blade cycloidal hydro-turbine, operated at a 2 m/s river. Computational fluid dynamic (CFD) analysis with sliding unstructured mesh is applied to investigate the extent how the dimensions of the duct affect the flow velocity to the turbine as well as the extracted power efficiency.

EXPERIMENTAL AND ANALYTICAL STUDIES OF VERTICAL AXIS WIND TURBINES

2018 ◽  
pp. 51-58
Author(s):  
B. P. Khozyainov
Keyword(s):  
Wind Turbine ◽  
Flow Velocity ◽  
Wind Power ◽  
Wind Turbines ◽  
Power Efficiency ◽  
Air Flow ◽  
Geometrical Parameters ◽  
Wind Speeds ◽  
Analytical Studies ◽  
Air Flow Velocity

The article carries out the experimental and analytical studies of three-blade wind power installation and gives the technique for measurements of angular rate of wind turbine rotation depending on the wind speeds, the rotating moment and its power. We have made the comparison of the calculation results according to the formulas offered with the indicators of the wind turbine tests executed in natural conditions. The tests were carried out at wind speeds from 0.709 m/s to 6.427 m/s. The wind power efficiency (WPE) for ideal traditional installation is known to be 0.45. According to the analytical calculations, wind power efficiency of the wind turbine with 3-bladed and 6 wind guide screens at wind speedsfrom 0.709 to 6.427 is equal to 0.317, and in the range of speed from 0.709 to 4.5 m/s – 0.351, but the experimental coefficient is much higher. The analysis of WPE variations shows that the work with the wind guide screens at insignificant average air flow velocity during the set period of time appears to be more effective, than the work without them. If the air flow velocity increases, the wind power efficiency gradually decreases. Such a good fit between experimental data and analytical calculations is confirmed by comparison of F-test design criterion with its tabular values. In the design of wind turbines, it allows determining the wind turbine power, setting the geometrical parameters and mass of all details for their efficient performance.

scholarly journals Measurement of flow velocity profiles in tank structures using the prototype device OCM Pro LR

2011 ◽  
Vol 64 (1) ◽  
pp. 263-270 ◽  
Author(s):  
K. Klepiszewski ◽  
M. Teufel ◽  
S. Seiffert ◽  
E. Henry
Keyword(s):  
Flow Velocity ◽  
Large Scale ◽  
Fluid Dynamic ◽  
Waste Water Treatment ◽  
Transport Processes ◽  
Treatment Efficiency ◽  
Cleaning Efficiency ◽  
Cfd Modelling ◽  
Ultrasonic Signals ◽  
Cfd Models

Generally, studies investigating the treatment efficiency of tank structures for storm water or waste water treatment observe pollutant flows in connection with conditions of hydraulic loading. Further investigations evaluate internal processes in tank structures using computational fluid dynamic (CFD) modelling or lab scale tests. As flow paths inside of tank structures have a considerable influence on the treatment efficiency, flow velocity profile (FVP) measurements can provide a possibility to calibrate CFD models and contribute to a better understanding of pollutant transport processes in these structures. This study focuses on tests carried out with the prototype FVP measurement device OCM Pro LR by NIVUS in a sedimentation tank with combined sewer overflow (CSO) situated in Petange, Luxembourg. The OCM Pro LR measurement system analyses the echo of ultrasonic signals of different flow depths to get a detailed FVP. A comparison of flow velocity measured by OCM Pro LR with a vane measurement showed good conformity. The FVPs measured by OCM Pro LR point out shortcut flows within the tank structure during CSO events, which could cause a reduction of the cleaning efficiency of the structure. The results prove the applicability of FVP measurements in large-scale structures.

scholarly journals Studi Fluiditas dan Karakteristik Aliran pada Pengecoran Al-Si Alloy Menggunakan Simulasi Numerik

2018 ◽  
Vol 1 (1) ◽  
pp. 007-012
Author(s):  
Andri Willy Adianta ◽  
Suprianto Suprianto ◽  
Arnius Daely ◽  
Mikael F. Bangun
Keyword(s):  
Aluminum Alloy ◽  
Flow Velocity ◽  
Computational Fluid Dynamic ◽  
Surface Defects ◽  
Fluid Dynamic ◽  
Liquid Aluminum ◽  
Flow Analysis ◽  
Pouring Temperature ◽  
Gravity Casting ◽  
Aluminum Castings

Aluminium silikon alloy merupakan paduan aluminium yang banyak digunakan dalam bidang teknik. Paduan ini memiliki kekuatan yang baik dan banyak diproduksi menjadi suatu komponen melalui proses pengecoran. Kandungan silikon dapat mengakibatkan penurunan fluiditas coran alumunium yang pada akhirnya akan menurunkan kualitas coran, fluiditas ini juga dipengaruhi temperatur pada saat penuangan alumunium cair. Penelitian ini bertujuan untuk mengetahui efek temperatur penuangan terhadap fluiditas, karakteristik aliran dan cacat coran pada pengecoran aluminium silikon alloy menggunakan cetakan pasir. Pengecoran dilakukan dengan gravity casting, analisa aliran simulasi meliputi distribusi kecepatan aliran, temperatur, tekanan, cacat permukaan dan fluiditas yang terjadi pada saat proses pengisian rongga cetak serta perbandingan fluiditas coran dan cacat permukaan pada eksperimental. Temperatur penuangan 685, 710, 735, 760 dan 785°C dengan ketebalan cetakan pola 1, 3, 5, 7, 9, dan 12 mm. Proses simulasi menggunakan software berbasis computational fluid dynamic. Hasil penelitian diperoleh temperatur tuang 785oC memiliki kecepatan aliran tertinggi yaitu sebesar ±0.145 m/s pada rongga 12 mm dan distribusi temperatur yang tinggi yaitu sebesar ±759 oC pada rongga 3 mm, sedangkan temperatur tuang 685oC memiliki distribusi tekanan yang tinggi yaitu sebesar ±107287 Pa pada rongga 6 mm. Cacat permukaan terbanyak pada temperatur tuang 785oC dan temperatur tuang 685oC paling sedikit. Fluiditas coran terbaik pada temperatur 785oC dimana rongga 12, 9, 7, 5 dan 3 mm terisi penuh dan 1 mm mencapai 181.4 mm.   Aluminum silicon alloy is an aluminum alloy that is widely used in engineering. This alloy has good strength and plenty of it are produced into a component through the casting process. Silicon content could result in a decrease in fluidity of aluminum castings which in turn would reduce the quality of casting. This fluidity is also influenced by temperature at the time of pouring liquid aluminum. This study aims to determine the effect of pouring temperature on fluidity, flow characteristics and casting defects on aluminum alloy silicon casting by using sand mold. Casting was conducted by gravity casting, simulation flow analysis including flow velocity distribution, temperature, pressure, surface and fluidity defects that occured during the process of filling the mold cavity as well as the comparison of the fluidity of castings and surface defects in the experiment. Casting temperatures was 685, 710, 735, 760 and 785°C with a mold thickness of patterns 1, 3, 5, 7, 9 and 12 mm. The simulation process used software based on computational fluid dynamic. The result showed pouring temperature of 785oC had the highest flow velocity of ± 0.145 m/s in 12 mm cavity and a high temperature distribution of ± 759oC in cavity of 3 mm, while the pouring temperature of 685oC had a high pressure distribution of ± 107287 Pa in 6 mm cavity. Most surface defects occurred at pour temperature of 785oC and the least at pour temperature of 685oC. The best castings liquidity occurred at temperature of 785oC where the cavity of 12, 9, 7, 5 and 3 mm was fully filled and 1 mm reached 181.4 mm.

Performance Optimization of Building Integrated-Mounted Wind Turbine

2012 ◽  
Vol 260-261 ◽  
pp. 69-76 ◽  
Author(s):  
Marco Milanese ◽  
Arturo de Risi ◽  
Domenico Laforgia
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Performance Optimization ◽  
Fluid Dynamic ◽  
Geometrical Parameters ◽  
Horizontal Axis Wind Turbine ◽  
Energy Devices ◽  
Two Factors ◽  
High Turbulence ◽  
Computation Fluid Dynamic

Building integrated-mounted wind turbine (BUWT) is one of the most promising renewable energy devices. However, this renewable energy technology is not fully spread principally due to two factors such as uncertainty in the prediction of wind velocity and high turbulence intensity around the building. In this work, the Taguchi method and the analysis of variance (ANOVA) on a horizontal-axis wind turbine has been applied, to study the influence of geometrical parameters such as building depth, width and height, as well as turbine position on the roof and turbine height. To evaluate the above-cited effects, the airflow around an isolated building of parametrical dimension has been simulated using a Computation Fluid Dynamic (CFD) code calibrated against experimental data in a previous paper from the authors. The results reported in the present paper outline the relative effects of the main building geometrical parameters on the performance of a rooftop installed wind turbine and establish basic guidelines for the optimal location of such turbines.

scholarly journals Multi Effect Evaporator Design Calculation for Brown Sugar Production using Computational Fluid Dynamics

2020 ◽  
Vol 9 (3S) ◽  
pp. 87-90
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Velocity ◽  
Performance Optimization ◽  
Cfd Simulation ◽  
Design Parameters ◽  
Design Calculation ◽  
Sugar Production ◽  
Brown Sugar ◽  
Process Stage

The industrial brown sugar production process is commonly started from grinding, filtering, first heating, sulfuric acid addition, decantation, and evaporation. Evaporation process is essential process stage in the production of brown sugar. The use of Multiple Effects Evaporator (MEE) has been becoming more common and plays an important role in the food industry, especially for producing high quality agricultural products. Therefore, several design parameters of MEE should be carefully considered such as pressure, temperature, and flow velocity. This study discusses the semi-iterative design of triple effect of feed forward system MEE for industrial-scale and simulation using Computational Fluid Dynamics (CFD). This study successfully determine the optimum value for the MEE parameters in the manufacture of brown sugar and also compared with Ms.Excel-Solver simulation. The CFD simulation indicates an accurate design process that can be employed to determine the effect of pressure, temperature, and flow velocity for MEE performance optimization.

scholarly journals Single-Beam Acoustic Doppler Profiler and Co-Located Acoustic Doppler Velocimeter Flow Velocity Data

Data ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 61
Author(s):  
Marilou Jourdain de Thieulloy ◽  
Mairi Dorward ◽  
Chris Old ◽  
Roman Gabl ◽  
Thomas Davey ◽  
...  
Keyword(s):  
Time Series ◽  
Flow Velocity ◽  
Numerical Models ◽  
Quality Data ◽  
Velocity Measurements ◽  
Ocean Energy ◽  
Data Set ◽  
Single Beam ◽  
Correlation Statistics ◽  
Acoustic Doppler Profiler

Acoustic Doppler Profilers (ADPs) are routinely used to measure flow velocity in the ocean, enabling multi-points measurement along a profile while Acoustic Doppler Velocimeters (ADVs) are laboratory instruments that provide very precise point velocity measurement. The experimental set-up allows laboratory comparison of measurement from these two instruments. Simultaneous multi-point measurements of velocity along the horizontal tank profile from Single-Beam Acoustic Doppler Profiler (SB-ADP) were compared against multiple co-located point measurements from an ADV. Measurements were performed in the FloWave Ocean Energy Research Facility at the University of Edinburgh at flow velocities between 0.6 ms − 1 and 1.2 ms − 1 . This paper describes the data; the analysis of the inter-instrument comparison is presented in an associated Sensors paper by the same authors. This data-set contains (a) time series of raw SB-ADP uni-directional velocity measurements along a 10 m tank profile binned into 54 measurements cells and (b) ADV point measurements of three-directional velocity time series recorded in beam coordinates at selected locations along the profile. Associated with the data are instrument generated quality data, metadata and user-derived quality flags. An analysis of the quality of SB-ADP data along the profile is presented. This data-set provides multiple contemporaneous velocity measurements along the tank profile, relevant for correlation statistics, length-scale calculations and validation of numerical models simulating flow hydrodynamics in circular test facilities.

scholarly journals Temporal dissociation between the minimal distal-to-aortic pressure ratio and peak hyperemia during intravenous adenosine infusion

2017 ◽  
Vol 312 (5) ◽  
pp. H992-H1001 ◽  
Author(s):  
Lorena Casadonte ◽  
Koen M. Marques ◽  
Jos A. E. Spaan ◽  
Maria Siebes
Keyword(s):  
Flow Velocity ◽  
Coronary Flow ◽  
Fluid Dynamic ◽  
Pressure Ratio ◽  
Aortic Pressure ◽  
Adenosine Infusion ◽  
Maximal Velocity ◽  
Systemic Hemodynamic ◽  
Stenosis Severity ◽  
Adenosine Administration

The present study sought to compare the temporal relation between maximal coronary flow (peak hyperemia) and minimal coronary-to-aortic pressure ratio (Pd/Pa) for intracoronary (IC) and intravenous (IV) adenosine administration. Peak hyperemia is assumed to coincide with the minimal Pd/Pa value. However, this has not been confirmed for systemic hemodynamic variations during IV adenosine infusion. Hemodynamic responses to IV and IC adenosine administration were obtained in 12 patients (14 lesions) using combined IC pressure and flow velocity measurements. A fluid dynamic model was used to predict the change in Pd/Pa for different stenosis severities and varying Pa. Hemodynamic variability during IV adenosine hyperemia was greater than during IC adenosine, as assessed by the coefficient of variation. During IV adenosine, flow velocity peaked 28 ± 4 (SE) s after the onset of hyperemia, while Pd/Pa reached a minimum (0.82 ± 0.01) 22 ± 7 s later ( P < 0.05), when Pa had declined by 6.1% and hyperemic velocity by 4.5% ( P < 0.01). Model outcomes corroborated the role of variable Pa in this dissociation. In contrast, maximal flow and minimal Pd/Pa coincided for IC adenosine, with IV-equivalent peak velocities and a higher Pd/Pa ratio (0.86 ± 0.01, P < 0.01). Hemodynamic variability during continuous IV adenosine infusion can lead to temporal dissociation of minimal Pd/Pa and peak hyperemia, in contrast to IC adenosine injection, where maximal velocity and minimal Pd/Pa coincide. Despite this variability, stenosis hemodynamics remained stable with both ways of adenosine administration. Our findings suggest advantages of IC over IV adenosine to identify maximal hyperemia from pressure-only measurements. NEW & NOTEWORTHY Systemic hemodynamic variability during intravenous adenosine infusion produces substantial temporal dissociation between peak hyperemia appraised by coronary flow velocity and the minimal distal-to-aortic pressure ratio commonly used to determine functional stenosis severity. This dissociation was absent for intracoronary adenosine administration and tended to be mitigated in patients receiving Ca2+ antagonists.

scholarly journals Anterior-to-posterior wave of buccal expansion in suction feeding fishes is critical for optimizing fluid flow velocity profile

2008 ◽  
Vol 5 (28) ◽  
pp. 1309-1316 ◽  
Author(s):  
Kristin L Bishop ◽  
Peter C Wainwright ◽  
Roi Holzman
Keyword(s):  
Velocity Profile ◽  
Flow Velocity ◽  
Prey Capture ◽  
Peak Flow ◽  
Fluid Dynamic ◽  
Time Lag ◽  
Mouth Opening ◽  
Suction Feeding ◽  
Peak Flow Velocity ◽  
Flow Velocity Profile

In fishes that employ suction feeding, coordinating the timing of peak flow velocity with mouth opening is likely to be an important feature of prey capture success because this will allow the highest forces to be exerted on prey items when the jaws are fully extended and the flow field is at its largest. Although it has long been known that kinematics of buccal expansion in feeding fishes are characterized by an anterior-to-posterior wave of expansion, this pattern has not been incorporated in most previous computational models of suction feeding. As a consequence, these models have failed to correctly predict the timing of peak flow velocity, which according to the currently available empirical data should occur around the time of peak gape. In this study, we use a simple fluid dynamic model to demonstrate that the inclusion of an anterior-to-posterior wave of buccal expansion can correctly reproduce the empirically determined flow velocity profile, although only under very constrained conditions, whereas models that do not allow this wave of expansion inevitably predict peak velocity earlier in the strike, when the gape is less than half of its maximum. The conditions that are required to produce a realistic velocity profile are as follows: (i) a relatively long time lag between mouth opening and expansion of the more posterior parts of the mouth, (ii) a short anterior portion of the mouth relative to more posterior sections, and (iii) a pattern of movement that begins slowly and then rapidly accelerates. Greater maximum velocities were generated in simulations without the anterior-to-posterior wave of expansion, suggesting a trade-off between maximizing fluid speed and coordination of peak fluid speed with peak gape.

scholarly journals Hydrodynamic Performance of the 3D Hydrofoil at the Coupled Oscillating Heave and Pitch Motions

2021 ◽  
Vol 71 (2) ◽  
pp. 1-18
Author(s):  
A.R. Abbasi ◽  
H. Ghassemi ◽  
G. He
Keyword(s):  
Flow Velocity ◽  
Power Efficiency ◽  
High Efficiency ◽  
Numerical Results ◽  
Hydrodynamic Performance ◽  
Power Performance ◽  
Power Extraction ◽  
Average Value ◽  
Low Efficiency ◽  
Lift And Drag

Abstract The purpose of this paper is to study on the power extraction of the hydrofoil by performance of the coupled oscillating heave and pitch motions. The numerical analysis is conducted by using the Reynolds Average Navier-Stokes (RANS) equations and the realizable k- ɛ turbulent model of the Star-CCM+ software. A 3D oscillating hydrofoil of NACA0015 section with aspect ratio of 7 is selected for the present analysis at two inflow velocities and three frequencies. The numerical results of lift and drag coefficients, horizontal and vertical forces coefficients, power efficiency in time domain and average value of those parameters are presented and discussed. According to the numerical results, the high efficiency of hydrofoil is found at the reduced frequency of 0.18 and the flow velocity of 1 m/s and the low efficiency is obtained at the reduction frequency of 0.06 and the flow velocity of 2 m/s. Moreover, the contour results of vorticity, streamline and pressure distribution are also presented and discussed. The computational model depicts clear vortex patterns surrounding the hydrofoil, which has a major impact on the power performance of oscillating hydrofoil.

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