Effect of Inlet Nozzle Shape on Performance of Darrieus-Type Hydro-Turbine Operated in Small Open Water Channel

2015 ◽  
Author(s):  
Kazuhiko Nakashima ◽  
Ryosuke Moriyama ◽  
Daisuke Matsusita ◽  
Satoshi Watanabe ◽  
Shin-ichi Tsuda ◽  
...  
Keyword(s):  
Open Channel ◽  
Constant Width ◽  
Water Channel ◽  
Open Water ◽  
Hydro Turbine ◽  
Turbine Performance ◽  
Straight Line ◽  
Low Head ◽  
Nozzle Shape ◽  
Converging Angle

A Darrieus-type hydro-turbine has been developed for the utilization of extra low head hydraulic energy. In the case of a ducted Darrieus-type hydro-turbine which consists of an intake, a runner, a casing and a draft tube, it has been found that the Darrieus runner with the narrow intake can generate larger torque without deterioration of efficiency than that with the parallel intake with the constant width. In this paper, the effect of the shape of the inlet nozzle on the performance of the Darrieus-type hydro-turbine operated in open channel flow is investigated both experimentally and numerically. Tested nozzles are two types of two-dimensional symmetric inlet nozzle, Half Diameter curved nozzle (HD nozzle) and Straight Line nozzle (SL nozzle). As a result, the Darrieus hydroturbine with SL nozzle generates larger power and yields higher efficiency than that with HD nozzle. In addition, the effects of nozzle converging angle and outlet width of SL nozzle on the turbine performance are investigated. As a result, it is found that the Darrieus hydroturbine with SL nozzle having large converging angle generates larger power with higher efficiency than that with the nozzle having small converging angle. And then, it is found that the generated power increases when SL nozzle with large outlet width is installed.

0707 Investigation of nozzle shape for Darrieus-type hydro-turbine with inlet nozzle in open channel flow

2014 ◽  
Vol 2014 (0) ◽  
pp. _0707-1_-_0707-4_
Author(s):  
Kazuhiko NAKASHIMA ◽  
Ryosuke MORIYAMA ◽  
Daisuke MATSUSITA ◽  
Satoshi WATANABE ◽  
Akinori FURUKAWA ◽  
...  
Keyword(s):  
Channel Flow ◽  
Open Channel ◽  
Open Channel Flow ◽  
Hydro Turbine ◽  
Nozzle Shape

scholarly journals Analysing Hydraulic Efficiency of Water Vortex Pico-Hydro Turbine using Numerical Method

2020 ◽  
Vol 77 (2) ◽  
pp. 91-101
Author(s):  
Ridho Irwansyah ◽  
Warjito ◽  
Budiarso ◽  
Christopher Clement Rusli ◽  
Sanjaya BS Nasution
Keyword(s):  
Internal Flow ◽  
Computational Method ◽  
Hydraulic Efficiency ◽  
Optimum Location ◽  
Optimum Ratio ◽  
Hydro Turbine ◽  
Turbine Efficiency ◽  
Turbine Performance ◽  
Low Head ◽  
Hydro Turbines

To overcome the lack of rural electricity in Indonesia vortex pico-hydro turbines are used as an option solution. This is due to the ability of the vortex turbine to work in low head conditions effectively. This study is conducted with comparison of curved and straight blade to obtain a more optimum turbine performance. Two methods are carried out in this study, analytical and computational method. Analytical methods are used to determine blade geometry and its performance while computational methods are used to analyse internal flow of turbine. As a result, the study concludes that hydraulic efficiency of vortex turbine in this study doesn’t affect much between straight and curved blades. The hydraulic efficiency for those blades is around 0.63. In addition, the study continued by analysing the optimum location of the blade in the basin. The results of the study show that the optimum ratio of depth and diameter of the blade is 0.33 with turbine efficiency is 0.84. Thus, the location of the blades is more important than the type of blades.

scholarly journals Experimental investigation of Archimedes Screw Hydro Turbine rotation with and without deflector

2021 ◽  
Vol 926 (1) ◽  
pp. 012013
Author(s):  
Y Setiawan ◽  
E S Wijianti ◽  
B S Wibowo ◽  
S Saparin ◽  
P Prayitnoadi
Keyword(s):  
Electrical Energy ◽  
Small Scale ◽  
Outer Diameter ◽  
Hydro Turbine ◽  
Turbine Performance ◽  
Screw Length ◽  
Water Turbine ◽  
Low Head ◽  
Pitch Distance ◽  
Hydro Turbines

Abstract The Archimedes screw water turbine (AST) is a device that works mechanically to produce electrical energy with an energy source that comes from the flow of water. Archimedes screw hydro turbines operate at low head and flow rates and can generate electricity at micro levels. This type of turbine is very suitable for use in small waters such as irrigation and rivers. The research was conducted by building a prototype of a small-scale Archimedes screw hydro turbine with and without deflector. The purpose of this research is to compare the rotation produced by the two turbines and whether the installation of a deflector can improve turbine performance. The turbine is constructed with a screw length of 1 m, outer diameter is 30 cm, the number of blades 15, and each has a pitch distance is 13 cm. Turbine angle variations are 30°, 35°, and 40°. The results showed that the best rotor rotation was produced by the screw without deflector at an angle of 30°. This shows that the addition of a deflector reduces the resulting screw rotation.

Boundaries Influence on the Flow Field Around an Oscillating Sphere

2013 ◽  
Author(s):  
Domenica Mirauda ◽  
Antonio Volpe Plantamura ◽  
Stefano Malavasi
Keyword(s):  
Free Surface ◽  
Flow Field ◽  
Boundary Conditions ◽  
Damping Ratio ◽  
Water Channel ◽  
Open Water ◽  
Free Surface Flows ◽  
The Body ◽  
Sphere Diameter ◽  
Oscillating Sphere

This work analyzes the effects of the interaction between an oscillating sphere and free surface flows through the reconstruction of the flow field around the body and the analysis of the displacements. The experiments were performed in an open water channel, where the sphere had three different boundary conditions in respect to the flow, defined as h* (the ratio between the distance of the sphere upper surface from the free surface and the sphere diameter). A quasi-symmetric condition at h* = 2, with the sphere equally distant from the free surface and the channel bottom, and two conditions of asymmetric bounded flow, one with the sphere located at a distance of 0.003m from the bottom at h* = 3.97 and the other with the sphere close to the free surface at h* = 0, were considered. The sphere was free to move in two directions, streamwise (x) and transverse to the flow (y), and was characterized by values of mass ratio, m* = 1.34 (ratio between the system mass and the displaced fluid mass), and damping ratio, ζ = 0.004. The comparison between the results of the analyzed boundary conditions has shown the strong influence of the free surface on the evolution of the vortex structures downstream the obstacle.

scholarly journals Investigation of pitch chord ratio effect on axial hydro turbine performance

2018 ◽  
Author(s):  
Nono Suprayetno ◽  
Priyono Sutikno ◽  
Nathanael P. Tandian ◽  
Firman Hartono
Keyword(s):  
Ratio Effect ◽  
Hydro Turbine ◽  
Turbine Performance

Effects of Design Variations of Rotor Entry Cavity Geometry on Shrouded Steam Turbine Performance

2010 ◽  
Author(s):  
K. G. Barmpalias ◽  
A. I. Kalfas ◽  
R. S. Abhari ◽  
Toshio Hirano ◽  
Naoki Shibukawa
Keyword(s):  
Steam Turbine ◽  
Constant Width ◽  
Main Flow ◽  
Volume Reduction ◽  
Efficiency Gain ◽  
Cavity Volume ◽  
Turbine Performance ◽  
Baseline Case ◽  
Stage Performance ◽  
Stage Efficiency

This paper presents an experimental study of the effect of geometry variations of the rotor entry cavity on shrouded steam turbine performance. A series of experiments was carried out where different configurations of the geometry of the entry cavity were tested. Blade geometry and tip clearance remained unaltered for all cases examined. Interactions between cavity and main flow are carefully investigated and their consequences on shrouded steam turbine stage efficiency are examined. Geometry variations of the entry cavity were installed in a pre-existing ‘baseline’ case of high efficiency. Five different test cases were examined. For the first two of these cases a ring having a constant width of 2mm and 4mm in radial direction is used. The next two cases employ a non-uniform, wavy insert and for the last case a backwards slanted insert is used that covers most of the inlet to cavity area, maintaining a safety distance of 2mm from the downstream rotor. The cases are divided into two groups, based on the same inlet cavity volume. The first group of three cases has a cavity volume reduction of 14% compared to the baseline case, whereas in the second group two cases are examined which maintain a 28% cavity volume reduction compared to the baseline case. Stage performance and flow field data were acquired and analyzed. Strong interactions between cavity and main flow are observed for all cases, not only at the location where the variations were installed. An observed effect can also be seen downstream of the rotor affecting the stage performance. Measurements were performed with the use of miniature probes ensuring minimum blockage effects especially within the cavity, both at rotor inlet as well as downstream of the second rotor. The use of a uniform geometry variation for the inlet rotor cavity in both groups proved to be the best in terms of stage efficiency. Although more complex and non-uniform variations were also used, the simple design of uniform geometry caused the least disturbance in the flow downstream of the 2nd rotor, having at the same time a moderate positive influence at the exit of the 2nd stator. The use of a constant width insert ring (thickness = 2mm) showed an efficiency gain of at least 0.3% from cases with 14% cavity volume reduction, whereas in the cases with 28% cavity volume reduction the use of a uniform ring of 4mm width produced a marginal efficiency gain of 0.1% at the operational point.

Design and Development of an Ultra Low Head Axial Hydro Turbine for Electricity Supply: Part I

2018 ◽  
Author(s):  
Jinbo Chen ◽  
Abraham Engeda
Keyword(s):  
Design Methodology ◽  
Water Flow Rate ◽  
Local Environment ◽  
Major Barrier ◽  
Hydro Turbine ◽  
Kaplan Turbine ◽  
Sufficient Power ◽  
Hydropower System ◽  
Low Head ◽  
The Impact

As a major resource for electricity, hydropower is widely used around the world for renewable energy. Traditionally, large high-capital cost dam equipped with large turbine system is preferred to produce sufficient power supply. However, recently large hydropower system is questioned because of the impact of dams on the local environment, which could be a major barrier for development of large hydropower system. Besides, billions people remain without access to electricity and most of them are in remote and rural location where is not suitable for large hydropower system. Therefore, the utilization of ultra-low-head (ULH) water energy (situations where the hydraulic head is less than 3m or the water flow rate is more than 0.5m/s with zero head) has becomes more attractive. Part I of this paper focus on developing a design methodology for a low-impact, damless Kaplan turbine system for ULH water resource.

Numerical Investigations on Intake Tube Design of Micro Kaplan Hydro-Turbine System

2016 ◽  
Author(s):  
Tarek ElGammal ◽  
Yi-Hsin Yen ◽  
Ryoichi S. Amano ◽  
Joseph Millevolte ◽  
Randal J. Mueller ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Numerical Study ◽  
Performance Outcomes ◽  
Design Parameters ◽  
Hydro Turbine ◽  
Eddy Simulation ◽  
Maximum Angle ◽  
Low Head ◽  
System Output ◽  
The Comparative Study

In this context, a numerical study was conducted to predict the performance of a small axial Kaplan hydro-turbine of 30 cm diameter that can be manufactured and installed vertically on a low head water level of less than 3 m. As a CFD simulation scheme, Large Eddy Simulation was selected to solve for the variables of turbulent flow due to its high fidelity performance for capturing time-variable turbulence wakes and eddies. Turbine intake tube dimensioning was primarily studied as an affecting element to maximize energy extraction with the set of initial design parameters. The intake tube was tested at six angles (3, 6, 9, 12, 15, 18 degrees) and four lengths (50, 60, 75, 90 cm). The simulations were performed on a pre-determined water height, one diffuser design, and one set of stator-rotor having a rotational speed of 750 rpm. Maximizing the efficiency of a system with less material cost was the primary goal of the comparative study. After that, bellmouth profile was adopted to find out its influence on the system performance. Outcomes have proven the merit of higher slope per side length in enhancing output power with an average of 2.7 percent by full expansion from minimum to the maximum angle. Moreover, a corresponding marginal efficiency raise was observed by increasing intake slope, while it was found that the system acts poorly with longer intake tubes as both power and efficiency go down. Bellmouth profiles, based on the guidelines of the best straight design, significantly improved system output to reach 81 percent efficiency.

scholarly journals Flow in open channel near draft tube outlet of low head turbine.

1991 ◽  
Vol 57 (533) ◽  
pp. 25-29
Author(s):  
Takaya KITAHORA ◽  
Tomitaro TOYOKURA ◽  
Hiroshi YAMAZAWA ◽  
Takashi KUBOTA ◽  
Ryouji SUZUKI
Keyword(s):  
Open Channel ◽  
Draft Tube ◽  
Low Head
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