scholarly journals Multi-objective Optimization of Draft Tube in Francis Turbine Using DOE, RBF and NSGA-II

2017 ◽  
Author(s):  
Chol Nam Mun ◽  
De Chun Ba ◽  
Xiang Ji Yue ◽  
Myong Il Kim
Keyword(s):  
Draft Tube ◽  
Fluid Dynamic ◽  
Hydraulic Turbine ◽  
Optimization Method ◽  
Approximate Model ◽  
Francis Turbine ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Design Matrix ◽  
Nsga Ii

In order to improve the performance of the draft tube in hydraulic turbine, a multi–objective optimization method for the draft tube is developed by combining the design of experiment (DOE), the radial basis function (RBF) and the non–dominated sorting genetic algorithm (NSGA–II) in this paper. The geometrical design variables of the median section in the draft tube and the cross section in its exit diffuser are considered as design parameters in this optimization, which objective function is to maximize the pressure recovery factor (Cp) and minimize the energy loss coefficient (ζ). The limited numbers of design matrix required for the shape optimization of the draft tube is generated by optimal Latin hypercube (OLH) method of the DOE technique, of which performances are evaluated through computational fluid dynamic (CFD) numerical simulation. For reducing of the computational consumption, the approximate model is used based on the RBF. The Pareto optimal solutions are finally performed using the NSGA–II for obtaining the best geometrical parameters of the draft tube. The optimization result of the draft tube shows a marked performance improvement over the original, which verifies the theoretical validity and feasibility of the proposed method in this paper.

scholarly journals Manipulation of the swirling flow instability in hydraulic turbine diffuser by different methods of water injection

2018 ◽  
Vol 180 ◽  
pp. 02090 ◽  
Author(s):  
Pavel Rudolf ◽  
Jiří Litera ◽  
Germán Alejandro Ibarra Bolanos ◽  
David Štefan
Keyword(s):  
Swirling Flow ◽  
Flow Instability ◽  
Draft Tube ◽  
Water Injection ◽  
Hydraulic Turbine ◽  
Operating Conditions ◽  
Francis Turbine ◽  
Necessary Condition ◽  
Vortex Rope ◽  
Wide Range

Vortex rope, which induces substantial pressure pulsations, arises in the draft tube (diffuser) of Francis turbine for off-design operating conditions. Present paper focuses on mitigation of those pulsations using active water jet injection control. Several modifications of the original Susan-Resiga’s idea were proposed. All modifications are driven by manipulation of the shear layer region, which is believed to play important role in swirling flow instability. While some of the methods provide results close to the original one, none of them works in such a wide range. Series of numerical experiments support the idea that the necessary condition for vortex rope pulsation mitigation is increasing the fluid momentum along the draft tube axis.

Design of a Francis Turbine for a Small Hydro Power Project in Turkey

2010 ◽  
Author(s):  
Kutay Celebioglu ◽  
Gizem Okyay ◽  
Mehmet Yildiz
Keyword(s):  
Power Plants ◽  
Parametric Design ◽  
Optimization Procedure ◽  
Hydraulic Turbine ◽  
Francis Turbine ◽  
Design Parameters ◽  
Hydro Power ◽  
Total Potential ◽  
Computational Fluid Dynamics Analysis ◽  
Hydro Power Plants

Many hydro power plants, both in small and large scales, are being constructed in Turkey. The total potential of these projects reach to 216 billion kWh of feasible energy. However a method was not yet developed for the design of hydraulic machinery equipment in Turkey. In order to accomplish the hydraulic turbine design without any prior information than the design parameters of the hydraulic project, a methodology is developed. This methodology involves the use of computational tools and it is applied for small hydro projects. This methodology is a parametric design-optimization procedure which consists of parametric geometry modeling, computational fluid dynamics analysis and structural verification.

scholarly journals Optimization of the Efficiency of a Michell–Banki Turbine Through the Variation of Its Geometrical Parameters Using a PSO Algorith

2021 ◽  
Vol 16 ◽  
pp. 37-46
Author(s):  
A. J. Perez-Rodriguez ◽  
J. Sierra-Del Rio ◽  
L. F. Grisales-Noreña ◽  
S. Galvis
Keyword(s):  
Processing Time ◽  
Mathematical Formulation ◽  
Optimization Method ◽  
Operating Conditions ◽  
Francis Turbine ◽  
Small Scale ◽  
Geometrical Parameters ◽  
Hydropower Generation ◽  
Swarm Optimization ◽  
Water Turbines

Small-scale hydropower generation can satisfy the needs of communities located near natural sources of flowing water. The operating conditions of a Michell–Banki Turbine (MBT) are relatively easier to meet than those of other types of turbine, making it useful in places where other devices are not suitable. Moreover, MBT efficiency is almost invariable with respect to flow rate conditions. Nevertheless, such efficiency commonly ranges between 70% and 85%, which is lower than that of other water turbines like Turgo, Pelton, or Francis turbine. The objective of this work is to determine the maximum theoretical efficiency of an MBT and its associated geometrical parameters by implementing Particle Swarm Optimization. The results show a higher effectiveness of the mathematical formulation compared with other cases from literature and show the performance of the optimization method proposed in this study in terms of solution and processing time. Finally, a maximum MBT efficiency of 93.3% was achieved

scholarly journals Design of Experiments Applied to Francis Turbine Draft Tube to Minimize Pressure Pulsations and Energy Losses in Off-Design Conditions

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3894
Author(s):  
Arthur Favrel ◽  
Nak-Joong Lee ◽  
Tatsuya Irie ◽  
Kazuyoshi Miyagawa
Keyword(s):  
Draft Tube ◽  
Pressure Fluctuations ◽  
Internal Flow ◽  
Francis Turbine ◽  
Energy Losses ◽  
Geometrical Parameters ◽  
Cfd Simulations ◽  
Part Load ◽  
Full Load ◽  
Load Conditions

This paper proposes an original approach to investigate the influence of the geometry of Francis turbines draft tube on pressure fluctuations and energy losses in off-design conditions. It is based on Design of Experiments (DOE) of the draft tube geometry and steady/unsteady Computational Fluid Dynamics (CFD) simulations of the draft tube internal flow. The test case is a Francis turbine unit of specific speed Ns=120 m-kW which is required to operate continuously in off-design conditions, either with 45% (part-load) or 110% (full-load) of the design flow rate. Nine different draft tube geometries featuring a different set of geometrical parameters are first defined by an orthogonal array-based DOE approach. For each of them, unsteady and steady CFD simulations of the internal flow from guide vane to draft tube outlet are performed at part-load and full-load conditions, respectively. The influence of each geometrical parameter on both the flow instability and resulting pressure pulsations, as well as on energy losses in the draft tube, are investigated by applying an Analysis of Means (ANOM) to the numerical results. The whole methodology enables the identification of a set of geometrical parameters minimizing the pressure fluctuations occurring in part-load conditions as well as the energy losses in both full-load and part-load conditions while maintaining the requested pressure recovery. Finally, the results of the CFD simulations with the final draft tube geometry are compared with the results estimated by the ANOM, which demonstrates that the proposed methodology also enables a rough preliminary estimation of the draft tube losses and pressure fluctuations amplitude.

scholarly journals Numerical Study on Performance Characteristics of Draft Tube of Mixed Flow Hydraulic Turbine

2012 ◽  
Vol 10 ◽  
pp. 48-52
Author(s):  
Ruchi Khare ◽  
Vishnu Prasad
Keyword(s):  
Coming Out ◽  
Draft Tube ◽  
Numerical Study ◽  
Flow Simulation ◽  
Hydraulic Turbine ◽  
Operating Conditions ◽  
Francis Turbine ◽  
Mixed Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Overall Performance

Draft tube is an important component of the hydraulic reaction turbine and affects the overall performance of turbine to a large extent. The flow inside the draft tube is complex because of the whirling flow coming out of runner and its diffusion along the draft tube. The kinetic energy coming out of runner is recovered in draft tube and part of recovery meets the losses. In the present work, the computational fluid dynamics (CFD) has been used for flow simulation in complete mixed flow Francis turbine for performance analysis for energy recovery, losses and flow pattern in an elbow draft tube used in Francis turbine at different operating conditions. The overall performance of the turbine at some typical operating regimes is validated with the experimental results and found to be in close comparison.DOI: http://dx.doi.org/10.3126/hn.v10i0.7103 Hydro Nepal Vol.10 January 2012 48-52

scholarly journals Optimization Design on Functionally Graded Cem for Trains Based on LPM Model with Calibrated Parameters

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Ruixian Qin ◽  
Bingzhi Chen
Keyword(s):  
Optimization Design ◽  
Optimization Method ◽  
Functionally Graded ◽  
Optimization Techniques ◽  
Design Parameters ◽  
Nsga Ii ◽  
Longitudinal Response ◽  
Lumped Parameter ◽  
1D Model ◽  
Crash Model

Lumped parameter modeling (LPM) combined with optimization techniques is an efficient approach for parametric configuration design of energy absorption to improve crashworthiness performance during train collision. This work proposed a simplified model by introducing a bar element to consider the influence of the carbody in a collision process. The optimization method is applied to calibrate the equivalent parameters of the bar element. Bar elements with calibrated parameters are adopted in establishing a one-dimensional (1D) model for the train crash. Subsequently, a novel crash energy management (CEM) mode with functionally graded energy (FGE) configuration is introduced to the train crash model for improving crashworthiness performance. The influence of parameters in graded function on interfacial force and peak acceleration is investigated and optimal design parameters are obtained by Nondominated Sorting Genetic Algorithm (NSGA-II). It is concluded that considering the behavior of the carbody can improve the accuracy of LPM in predicting the longitudinal response, and the gradient CEM is a potential energy configuration mode to improve the crashworthiness of the train in a collision.

scholarly journals CFD Analysis on Francis Turbine to Analyse Erosion Wear Due to Sediment Flow

2021 ◽  
Vol 7 (6) ◽  
pp. 1-13
Author(s):  
Uttam Singh Yadav ◽  
Shravan Vishwakarma ◽  
Jitendra Mishra
Keyword(s):  
Particle Size ◽  
Draft Tube ◽  
Francis Turbine ◽  
Geometrical Parameters ◽  
Erosion Wear ◽  
Steady State Condition ◽  
Erosion Damage ◽  
Computational Fluid Dynamics Analysis ◽  
Erosion Effect ◽  
Sand Particles

In present work Computational fluid dynamics analysis based erosion wear prediction is performed for Francis turbine components, especially the runner. For the geometrical parameters, Francis turbine model with steady state condition and viscous flow turbulence SST model using ANSYS Fluent. The erosion effect on all the three component such as spiral casing, runner & draft tube has been studied for different concentration of sand particles from 1% - 6%. For each of those concentration the effect of variation in size has been studied for different sizes 10 ?m - 80 ?m. Further the effect of total erosion was also analyzed for different particle size. Erosion damage is found close to the upper and lower portions of the leading edge of the stay vane. some erosion spots at guide vane on the blade pressure side where suction side has minimum erosion. Maximum erosion damage observed on runner especially at the middle of the blade. The draft tube situated closer to runner having highest velocity due to high absolute velocity of water coming out from the runner does not produce any serious erosion effect. Results shows that erosion rate is maximum on runner at particle size 80 ?m for all sand concentration 1% to 6%  and minimum at 30 ?m. Thus, 30 ?m is the optimum size of sand particles for the erosion.

3D Unsteady Turbulent Simulation of the Runaway Transient of the Francis Turbine

2007 ◽  
Author(s):  
Jinwei Li ◽  
Yulin Wu ◽  
Shuhong Liu ◽  
Yuliang Zhu
Keyword(s):  
Transient Process ◽  
Stokes Equations ◽  
Draft Tube ◽  
Guide Vane ◽  
Hydraulic Turbine ◽  
Moment Equation ◽  
Francis Turbine ◽  
Navier Stokes ◽  
Volume Discharge ◽  
Navier Stokes Equations

Based on Reynolds-averaged continuity and Navier-Stokes equations, and moment equation of the rotational system in the accelerated rotational relative coordinate, the governing equations of the runner region are obtained. The runaway transient simulation of the Francis turbine based on HL220 is made with RNG k-ε turbulence model under 9 guide vane openings. The variation diagrams of volume discharge, moment, rotational speed, and efficiency with respect to time are gained. Through further analysis of simulation results the transient process curve as well as the flow pattern under 9 guide vane openings are obtained, and detailed analysis is focused on flow in the draft tube to obtain variation of pressure distribution on symmetry surface of the draft tube with respect to time and pressure fluctuation of all test points in the turbine. Comparison between simulation and experiment results shows that they both are in good agreement, and it demonstrates that variation of all the parameters of the hydraulic turbine can be forecast accurately during the transient process.

Numerical Simulation of Pressure Fluctuation in Draft Tube of Large Francis Turbine

2007 ◽  
Author(s):  
Cuilin Liao ◽  
Fujun Wang ◽  
Xiaoqin Li ◽  
Yuliang Zhu
Keyword(s):  
Pressure Fluctuation ◽  
Swirling Flow ◽  
Transport Model ◽  
Draft Tube ◽  
Numerical Study ◽  
Hydraulic Turbine ◽  
Dominant Frequency ◽  
Numerical Results ◽  
Francis Turbine ◽  
Pressure Amplitude

The pressure fluctuation caused by swirling flow in draft tube is one of the main reasons of vibration in hydraulic turbine. It directly affects the steady operation of hydraulic turbine unit. The pressure fluctuation in draft tube of a large Francis turbine can’t be obtained accurately by similarity law from model test, and prototype test is difficult to carry out and costs too much. Therefore, it is necessary to predict pressure fluctuation in draft tube numerically and provide scientific reference for mitigating and suppressing pressure fluctuation. This paper describes a numerical study of unsteady flow in the draft tube of a large Francis turbine in a Hydropower Station of China by using the Reynolds averaged Navier–Stokes (RANS) approach with a Reynolds stress transport model (RSM), validating the numerical results against experimental data. The numerical results successfully represent the vortex rope. The pressure fluctuation patterns in different parts of the draft tube including the cone, elbow and diffuser are analyzed. The pressure fluctuation in the cone and elbow is relative steady, and it has an obvious dominant frequency which is approximately 0.28 and 0.3 times of the runner rotational frequency. These results show very good agreement with experiments. The largest pressure amplitude appears in the draft tube cone downstream side and the draft elbow inside. The pressure fluctuation in the diffuser is stochastic, and the amplitude is small. Additionally, the pressure distributions on the horizontal computational section of the draft tube are analyzed.

Optimum Design of Shell and Tube Heat Exchanger Using Response Surface Methodology

2014 ◽  
Vol 984-985 ◽  
pp. 1091-1094
Author(s):  
Vetrivel Kumar Kandasamy ◽  
Saravanan Muthusamy ◽  
Prabakaran M. Pitchamuthu
Keyword(s):  
Response Surface Methodology ◽  
Heat Exchanger ◽  
Response Surface ◽  
Optimum Design ◽  
Fluid Dynamic ◽  
Geometrical Parameters ◽  
Design Matrix ◽  
Optimum Result ◽  
Tube Heat Exchanger ◽  
Shell And Tube

The design process of shell and tube heat exchanger is difficult due to the complex geometric parameters with thermodynamic and fluid dynamic factors, which consume more time and minimum possibility for an optimum result in the case of conventional design. The optimum design of shell and tube heat exchanger was determined to predict optimum heat transfer coefficient with the effect of geometrical parameters such as number of baffles (NB), Shell diameter (Ds), Tube pitch (Pt) and Baffle spacing (LB). The analytical calculations were done using Response Surface Methodology on four factors, three level, central composite face centered design matrix with full replications technique by 95% confidence level. The results indicate that the geometrical parameters with optimum design.

Sign in / Sign up

Export Citation Format

Share Document