scholarly journals Numerical simulation of turbulence flow in a Kaplan turbine -Evaluation on turbine performance prediction accuracy-

2014 ◽  
Vol 22 (2) ◽  
pp. 022006 ◽  
Author(s):  
P Ko ◽  
S Kurosawa
Keyword(s):  
Numerical Simulation ◽  
Performance Prediction ◽  
Prediction Accuracy ◽  
Kaplan Turbine ◽  
Turbulence Flow ◽  
Turbine Performance

Comparison of Wind Turbine Performance Prediction and Measurement

1982 ◽  
Vol 104 (2) ◽  
pp. 84-88 ◽  
Author(s):  
J. L. Tangler
Keyword(s):  
Test Data ◽  
Wind Turbines ◽  
Performance Prediction ◽  
State Of The Art ◽  
Correlation Study ◽  
Performance Models ◽  
Rocky Flats ◽  
Turbine Performance ◽  
Horizontal Axis Wind Turbines ◽  
Development Center

The purpose of this work was to evaluate the state-of-the-art of performance prediction for small horizontal-axis wind turbines. This effort was undertaken since few of the existing performance methods used to predict rotor power output have been validated with reliable test data. The program involved evaluating several existing performance models from four contractors by comparing their predictions for two wind turbines with actual test data. Test data were acquired by Rocky Flats Test and Development Center and furnished to the contractors after submission of their prediction reports. The results of the correlation study will help identify areas in which existing rotor performance models are inadequate and, where possible, the reasons for the models shortcomings. In addition, several problems associated with obtaining accurate test data will be discussed.

scholarly journals Study of the Effect of Bulb Ratio and Blade Angle on Propeller Turbine Performance in Horizontal Flow using Numerical Simulation

Teknik ◽  
2020 ◽  
Vol 41 (1) ◽  
pp. 9-13
Author(s):  
Akhmad Nurdin ◽  
Dwi Aries Himawanto ◽  
Syamsul Hadi
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Flow Simulation ◽  
Water Velocity ◽  
Horizontal Flow ◽  
Blade Angle ◽  
Static State ◽  
Turbine Performance ◽  
Solid Works

This paper discusses numerical simulations of horizontal flow propeller turbines. Static bulbs located before the turbine can be used to increase water velocity and potentially increase the turbine's performance. The blade angle affects the gap between the blades, and this will also affect the performance of the turbine. Numerical simulations were conducted by using software Solid Works Flow Simulation 2016 and by using five blades in a static state. This study aimed to determine the effect of the bulb ratio and blade angle on the propeller turbine characteristics on horizontal flow. Bulb Ratio variations used in this study were 0, 0.4, 0.6, and 0.8, while the angle variations used were 20, 25, and 30 degrees. Each variation was tested at 0.02 m3/second. The results of this study indicated that the bulb ratio 0.6 with the 25-degree blade angle produces the highest torque

scholarly journals Flow and Fast Fourier Transform Analyses for Tip Clearance Effect in an Operating Kaplan Turbine

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 264 ◽  
Author(s):  
Hyoung-Ho Kim ◽  
Md Rakibuzzaman ◽  
Kyungwuk Kim ◽  
Sang-Ho Suh
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Tip Clearance Flow ◽  
Kaplan Turbine ◽  
Turbine Performance ◽  
Wide Range ◽  
Clearance Flow ◽  
Fft Analysis

The Kaplan turbine is an axial propeller-type turbine that can simultaneously control guide vanes and runner blades, thus allowing its application in a wide range of operations. Here, turbine tip clearance plays a crucial role in turbine design and operation as high tip clearance flow can lead to a change in the flow pattern, resulting in a loss of efficiency and finally the breakdown of hydro turbines. This research investigates tip clearance flow characteristics and undertakes a transient fast Fourier transform (FFT) analysis of a Kaplan turbine. In this study, the computational fluid dynamics method was used to investigate the Kaplan turbine performance with tip clearance gaps at different operating conditions. Numerical performance was verified with experimental results. In particular, a parametric study was carried out including the different geometrical parameters such as tip clearance between stationary and rotating chambers. In addition, an FFT analysis was performed by monitoring dynamic pressure fluctuation on the rotor. Here, increases in tip clearance were shown to occur with decreases in efficiency owing to unsteady flow. With this study’s focus on analyzing the flow of the tip clearance and its effect on turbine performance as well as hydraulic efficiency, it aims to improve the understanding on the flow field in a Kaplan turbine.

Predicting lean blow-off limit of gas turbine combustors based on Damköhler number and detailed atomization information

2020 ◽  
pp. 095765092092003
Author(s):  
Zhonghao Wang ◽  
Bin Hu ◽  
Aibing Fang ◽  
Aiming Deng ◽  
Junhua Zhang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Gas Turbine ◽  
Calculation Method ◽  
Time Scale ◽  
Prediction Accuracy ◽  
Drop Size ◽  
Prediction Method ◽  
Negative Effects ◽  
Supply Pressure ◽  
Uniform Model

A hybrid lean blow-off prediction method based on Damköhler ( Da) number was proposed in the authors’ previous study. However, the uniform model for fuel drop size distribution cannot fully reflect the actual atomization quality under lean blow-off conditions, which has negative effects on prediction accuracy. In the current study, atomization experiments are conducted under different fuel supply pressure. The atomization quality is described by Rosin–Rammler model and is integrated into numerical simulation. The calculation method of chemical time scale ( τc) is improved by accurately differentiating the inlet and outlet surface of reaction zone. After the improvement, the Da number under lean blow-off conditions mainly lies between 0.3 and 0.8, while under the designing condition, the Da number is about 20. Compared with the former method, the optimized method in the present article can distinguish stable combustion states markedly from lean blow-off states. Through the introduction of detailed atomization information and the improvement of time scale calculation, lean blow-off prediction accuracy in the present work is efficiently improved, which can provide powerful technical support for engineering applications.

Unsteady Performance Prediction of a Single Entry Mixed Flow Turbine Using 1-D Gas Dynamic Code Extended With Meanline Model

2012 ◽  
Author(s):  
Meng Soon Chiong ◽  
Srithar Rajoo ◽  
Alessandro Romagnoli ◽  
Ricardo Martinez-Botas
Keyword(s):  
Performance Prediction ◽  
Computational Models ◽  
Power Prediction ◽  
Mixed Flow ◽  
Pulse Flow ◽  
Turbine Performance ◽  
Gas Dynamic ◽  
Wide Range ◽  
Single Entry ◽  
Turbine Model

Turbochargers are widely regarded as one of the most promising enabling technology for engine downsizing, in the aim to achieve better specific fuel consumption, thermal efficiency and most importantly carbon reduction. The increasing demand for higher quality engine-turbocharger matching, leads to the development of computational models capable of predicting the unsteady behaviour of a turbocharger turbine when subjected to pulsating inlet flow. Due to the wide range of engine loads and speed variations, an automotive turbocharger turbine model must be able to render all the frequency range of a typical exhaust pulse flow. A purely one-dimensional (1-D) turbine model is capable of good unsteady swallowing capacity prediction, provided it is accurately validated. However, the unsteady turbine power evaluation still heavily relies on the quasi-steady assumption. On the other hand, meanline model is capable of resolving the turbine work output but it is limited to steady state flow due to its zero dimensional nature. This paper explores an alternative methodology to realize turbine unsteady power prediction in 1-D by integrating these two independent modelling methods. A single entry mixed-flow turbine is first modelled using 1-D gas dynamic method to solve the unsteady flow propagation in turbine volute while the instantaneous turbine power is subsequently evaluated using a mean-line model. The key in the effectiveness of this methodology relies on the synchronization of the flow information with different time-scales. In addition to the turbine performance parameters, the common level of unsteadiness was also compared based on the Strouhal number evaluations. Comparison of the quasi-steady assumption using the experiment results was made in order to further understand the strength and weaknesses of corresponding method in unsteady turbine performance prediction. The outcomes of the simulation showed a good agreement in the shape and trend profile for the instantaneous turbine power. Meanwhile the predicted cycle-averaged value indicates a positive potential of the current turbine model to be expanded to a whole engine simulation after few minor improvements.

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