Three-Dimensional Unsteady Simulation in a Water Turbine

This paper introduces the 3D numerical simulation of unsteady turbulent flow in the entire flow passage of a water turbine model with CFD technology. A new and available method for the design of a Francis turbine has been explored. The boundary conditions have been implemented based on the 3D averaged N-S equations. The governing equations are discreted on space by the finite volume method and on time step by the finite difference method. The 3D unsteady turbulent flow in an entire Francis turbine model is calculated successfully using the CFX-TASCflow software and RNG k-εturbulence model. Transient flow fields are simulated in the spiral case, the distributor, the runner and the draft tube. It is presented in this paper that the computer simulation of the flow fields in components of the Francis turbine at the optimum operating condition. Meanwhile, the velocity and pressure at any points in the flow fields can be obtained so as to provide the great value on the performance prediction. According to the simulating results, the flow analysis and the design experience, the design of components in a Francis turbine model can be improved and optimized. In this way, designers may decrease numbers of test and shorten the period for a model. Therefore, the cost of research and produce can be reduced.

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Performance Evaluation of Gear Pump by 2D Unsteady CFD Analysis

ASME 2013 Gas Turbine India Conference ◽

10.1115/gtindia2013-3607 ◽

2013 ◽

Cited By ~ 1

Author(s):

K. Anil Kumar ◽

N. Balamuralikrishnan

Keyword(s):

Mass Flow ◽

Transient Flow ◽

Flow Analysis ◽

Adverse Pressure Gradient ◽

Implant Design ◽

Gear Pump ◽

Time Step ◽

Design Synthesis ◽

Angular Velocities ◽

Rotation Motion

Gas Turbine development activities have been associated with development of different pumps and its allied subsystems used for fuel supply and lubrication oil supply at different engine operating condition. 2D transient flow analysis of a Dual pump has been carried out in an environment with an adverse pressure gradient to map important parameters like pressure, velocity, mass flow and effect of slip. Three achievable close tolerances were selected and carried out the analysis. Finally identified tolerance to be maintained during manufacturing based on the analysis. A moving dynamic mesh concept was adopted because of its capability to facilitate solving transient flow problem and motion of the domain boundaries. A simulated motion control was decided based on the time step, angular velocities of gears rotation motion and coded through a User defined function (UDF) to give angular momentum. Each analysis was carried out for 180 degree of rotation. The main parameter mass flow rate was monitored for different speed and outlet pressures. A validation experimental test was carried out at one rpm thus build up a confidence in implant design synthesis to meet challenges in future.

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3D unsteady turbulent flow analysis in a Francis turbine runner at nominal and off-design operating conditions

Vietnam Journal of Mechanics ◽

10.15625/0866-7136/26/3/5699 ◽

2004 ◽

Vol 26 (3) ◽

pp. 148-156

Author(s):

Pham Thi Kim Loan ◽

Bui Van Ga

Keyword(s):

Turbulent Flow ◽

Flow Analysis ◽

Operating Conditions ◽

Design Flow ◽

Francis Turbine ◽

Navier Stokes ◽

Medium Size ◽

Turbine Runner ◽

Design Values ◽

Physical Phenomena

This paper presents the use of a commercial Navier-Stokes turbulent flow code (FLUENT) as a mean to evaluate the behavior of a Francis turbine runner for the design and off-design conditions. The flow in the runner is analyzed numerically at different operating points. The numerical results permit to observe physical phenomena in the runner that are important in the process of hydraulic turbo machinery design. Values of different velocity components in the flow, blade pressure distribution ... given by the model are compared with experimental data at nominal and off-design flow conditions. Computer resource involves in the flow analysis should be compatible with the need of design process of a runner. Therefore 12 hours of CPU time can be considered as acceptable for calculating at each operating point on a computer workstation of medium size power.

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Mixing interface algorithm for 3D turbulent flow analysis of the GAMM Francis turbine

Modelling Fluid Flow ◽

10.1007/978-3-662-08797-8_25 ◽

2004 ◽

pp. 359-372 ◽

Cited By ~ 3

Author(s):

Sebastian Muntean ◽

Romeo F. Susan-Resiga ◽

Ioan Anton

Keyword(s):

Turbulent Flow ◽

Flow Analysis ◽

Francis Turbine ◽

Interface Algorithm

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A Numerical Study of BWR Steam Separator

Computational Technologies for Fluid/Thermal/Structural/Chemical Systems With Industrial Applications, Volume 1 ◽

10.1115/pvp2002-1566 ◽

2002 ◽

Author(s):

Haruo Terasaka ◽

Sensuke Shimizu

Keyword(s):

Transient Flow ◽

Numerical Study ◽

Fluid Model ◽

Flow Analysis ◽

Phase Flow ◽

Step Size ◽

Time Step ◽

Two Phase ◽

Time Step Size ◽

Steam Separator

An advanced numerical method based on two-fluid model of two-phase flow has been developed to simulate the swirling gas-liquid flow and the phase separation process in a Boiling Water Reactor separator. The goal is to correctly predict the performance of operating steam separator as well as new designs. The solution method present here is an extension of SIMPLEST scheme, a fully implicit scheme for single-phase flow analysis. It is robust and unconditionally stable, therefore enable us to use very large time step size. This feature is suitable for steady and/or slow transient flow analyses. Furthermore, it enhances numerical stability during rapid transient calculations. By employing this method, separator hydrodynamics around swirler were calculated.

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A Numerical Simulation of Swirling Two-Phase Flow in BWR Steam-Water Separator and Its Optimization

Volume 1: Fora, Parts A, B, C, and D ◽

10.1115/fedsm2003-45185 ◽

2003 ◽

Author(s):

Haruo Terasaka ◽

Sensuke Shimizu ◽

Minoru Kawahara

Keyword(s):

Transient Flow ◽

Fluid Model ◽

Flow Analysis ◽

Phase Flow ◽

Step Size ◽

Time Step ◽

Two Phase ◽

Time Step Size ◽

Fully Implicit ◽

Water Separator

An advanced numerical method based on the two-fluid model has been developed. The solution method presented here is an extension of the SIMPLEST scheme, a fully implicit scheme for single-phase flow analysis. It is robust and unconditionally stable, and therefore it enables us to use a very large time step size. This feature is suitable for steady and/or slow transient flow analyses. Furthermore, it enhances numerical stability during rapid transient calculations. By using this method, swirling gas-liquid flow in a steam-water separator of Boiling Water Reactors (BWRs) was calculated and the hydrodynamics characteristics were investigated for optimization.

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Nonisothermal Transient Flow in Natural Gas Pipeline

Journal of Applied Mechanics ◽

10.1115/1.2840046 ◽

2008 ◽

Vol 75 (3) ◽

Cited By ~ 48

Author(s):

M. Abbaspour ◽

K. S. Chapman

Keyword(s):

Gas Flow ◽

Transient Flow ◽

Flow Analysis ◽

Compressibility Factor ◽

Momentum Equation ◽

Gas Pipeline ◽

Time Step ◽

Inertia Term ◽

Fully Implicit ◽

Energy Equations

The fully implicit finite-difference method is used to solve the continuity, momentum, and energy equations for flow within a gas pipeline. This methodology (1) incorporates the convective inertia term in the conservation of momentum equation, (2) treats the compressibility factor as a function of temperature and pressure, and (3) considers the friction factor as a function of the Reynolds number and pipe roughness. The fully implicit method representation of the equations offers the advantage of guaranteed stability for a large time step, which is very useful for gas pipeline industry. The results show that the effect of treating the gas in a nonisothermal manner is extremely necessary for pipeline flow calculation accuracies, especially for rapid transient process. It also indicates that the convective inertia term plays an important role in the gas flow analysis and cannot be neglected from the calculation.

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CFD analysis of operational flow nature of a wind turbine model using environmental wind data from Nigerian Defence Academy (NDA)

Nigerian Journal of Technology ◽

10.4314/njt.v40i4.9 ◽

2021 ◽

Vol 40 (4) ◽

pp. 623-630

Author(s):

M. Samuel ◽

S.U. Muhammad ◽

W.C. Solomon ◽

G.C. Japheth

Keyword(s):

Wind Speed ◽

Turbulent Flow ◽

Wind Turbine ◽

Flow Analysis ◽

Cfd Analysis ◽

Model Design ◽

Wind Speeds ◽

Operational Flow ◽

Turbine Model

A wind turbine is a machine which converts the power in the wind into electricity. It operates under varying wind speeds depending on the environmental wind conditions. In this paper, we have presented the operational flow analysis of a proposed wind turbine model in Nigerian Defence Academy (NDA) Kaduna. The case study is for 5.6m/s, 7.5m/s and 9.5m/s wind speed. The model design and assembly of the components were done with the help of SolidWorks 2018 and the operational flow analysis done with ANSYS 15.0. The result showed that the flow nature of the turbine model grew from laminar flow to turbulent flow increasingly with the environmental wind speed. The flow nature remained laminar from 0.0356 to 1780 Reynolds at 5.6m/s. At 7.5m/s wind speed, from laminar 0.403 Reynolds to turbulent 4290 Reynolds and at 9.5m/s, from laminar 0.381 Reynolds to turbulent 4900 Reynolds. High turbulent flow and mass imbalance nature depicts that phenomenon like wake and vibration of the system occurred.

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