A Navier-Stokes Analysis of Three-Dimensional Turbulent Flows Inside Turbine Blade Rows at Design and Off-Design Conditions

1984 ◽  
Vol 106 (2) ◽  
pp. 421-429 ◽  
Author(s):  
C. Hah
Keyword(s):  
Turbulent Flows ◽  
Turbine Blade ◽  
Numerical Scheme ◽  
Control Volume ◽  
Three Dimensional ◽  
Leading Edge ◽  
Reynolds Stress Model ◽  
Navier Stokes ◽  
Governing Equations ◽  
Navier Stokes Equation

A numerical scheme based on the compressible Navier-Stokes equation has been developed for three-dimensional turbulent flows inside turbine blade rows. The numerical scheme is based on a fully conservative control volume formulation and solves the governing equations in fully elliptic form. Higher order discretizations are used for the convection term to reduce the numerical diffusion. An algebraic Reynolds stress model modified for the effects of the streamline curvature and the rotation is used for the closure of the governing equations. General coordinate transformations are used to represent the complex blade geometry accurately, and a grid generation technique based on elliptic partial differential equations is employed. Comparisons with the experimental data show that various complex three-dimensional viscous flow phenomena (three-dimensional flow separation near the leading edge, formation of the horseshoe vortex, etc.) are well predicted with the present method.

scholarly journals Numerical Solution of Three-Dimensional Turbulent Flows for Modern Gas Turbine Components

1987 ◽  
Author(s):  
C. Hah ◽  
J. H. Leylek
Keyword(s):  
Gas Turbine ◽  
Turbulent Flows ◽  
Gas Turbines ◽  
Solid Wall ◽  
Control Volume ◽  
Three Dimensional ◽  
Computer Code ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Aerodynamic Loss

This paper describes the development and assessment of a computer code for three-dimensional compressible turbulent flows in modern gas turbine components. The code is based on a high-order upwinding relaxation scheme with fully conservative control volume. A three-dimensional Reynolds-averaged Navier-Stokes equation is solved with a two-equation turbulence model that has a low Reynolds number modification near the solid wall. The code is applied to the study of compressible flow inside turbine blade rows of modern gas turbines. Measured data and calculations are carefully compared for the production and convection of aerodynamic loss to evaluate the code as an advanced design technique. The predicted aerodynamic performance is further compared with predictions based on current design techniques.

Prediction of Particle Impact on an Archimedes Screw Runner Blade for Micro Hydro Turbine

2013 ◽  
Vol 465-466 ◽  
pp. 552-556
Author(s):  
Muhammad Ammar Nik Mutasim ◽  
Nurul Suraya Azahari ◽  
Ahmad Alif Ahmad Adam
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Navier Stokes ◽  
Particle Impact ◽  
Three Dimensional Flow ◽  
Navier Stokes Equation ◽  
Runner Blade ◽  
Computational Fluid Dynamics Cfd ◽  
The Subject ◽  
The Impact

Energy is one of the most important sources in the world especially for developing countries. The subject study is conducted to predict the behaviour of particle due to errosion from the river through the achimedes screw runner and predict the impact of particle toward blade surface. For this reason, computational fluid dynamics (CFD) methods are used. The three-dimensional flow of fluid is numerically analyzed using the Navier-Stokes equation with standard k-ε turbulence model. The reinverse design of archimedes screw blade was refered with the previous researcher. Flow prediction with numerical results such as velocity streamlines, flow pattern and pressure contour for flow of water entering the blade are discussed. This study shows that the prediction of particle impact occurs mostly on the entering surface blade and along the leading edge of the screw runner. Any modification on the design of the screw runner blade can be analyze for further study.

Three Dimensional Measurements of a Turbine Blade Using Magnetic Resonance Thermometry and Magnetic Resonance Velocimetry

2017 ◽  
Author(s):  
Elliott T. Williams ◽  
Daniel C. Caniano ◽  
Gregory Davis ◽  
Angus M. Ferrell ◽  
Michael J. Benson ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Turbulent Flows ◽  
Turbine Blade ◽  
Three Dimensional ◽  
Leading Edge ◽  
Optical Measurements ◽  
Internal Cooling ◽  
Complex Flow ◽  
Full Field ◽  
Magnetic Resonance Velocimetry

A hollowed NACA-0012 airfoil with removable inserts was developed to study the complex flow through two interior chambers. The geometry represented an internally cooled gas turbine blade with internal impingement in several locations. A fully turbulent water flow passed the airfoil. Within the airfoil, a second fluid at a different temperature was mixed through the insert nearest the leading edge and recirculated to the aft chamber for additional internal cooling before exiting the airfoil as film cooling on the suction side and at the trailing edge. Time-averaged, three-dimensional temperature and three-component velocity measurements were collected using Magnetic Resonance Imagery (MRI) based techniques. Magnetic Resonance Velocimetry (MRV) and Thermometry (MRT) are techniques for measuring the velocity and temperature of fully turbulent flows at sub-millimeter-scale resolution. The benefits of these techniques over similar measuring techniques include the ability to collect full-field, three-dimensional, nonintrusive, non-optical measurements for conjugate heat transfer simulation validation in complex, turbulent flows. Multiple MRI-based techniques can be combined within the same experiment to explore the interaction between the mean fields of multiple quantities. The experimental setup employed in this work produced time-averaged velocity and temperature data illustrating flow details through the airfoil’s interior chambers and heat flux through the entire airfoil and at specific locations.

scholarly journals A Numerical Study of Three-Dimensional Flow Separation and Wake Development in an Axial Compressor Rotor

1984 ◽  
Author(s):  
C. Hah
Keyword(s):  
Viscous Flow ◽  
Turbulent Flows ◽  
Numerical Study ◽  
Control Volume ◽  
Turbulent Transport ◽  
Three Dimensional ◽  
Numerical Procedure ◽  
Computational Procedure ◽  
Navier Stokes Equation ◽  
Compressor Rotor

A computational procedure based on the compressible Reynolds-averaged Navier-Stokes equation has been developed for the viscous flow through an isolated compressor rotor. The numerical scheme is based on fully conservative control volume formulation and solves various conservation equations in fully elliptic form on the rotating coordinates fixed on the rotor. An algebraic Reynolds stress model is used to describe the turbulent transport terms. The numerical procedure has been applied to predict three-dimensional turbulent flows through two different isolated compressor rotors. The detailed quantitative comparisons with two sets of well-documented data show that the developed computational procedure predicts the viscous flow development over the blading and in the wake with the accuracy satisfactory for most engineering purposes; the computer code can be used for the guidance of advanced rotor design.

scholarly journals FINITE VOLUME METHODDISCRETIZATION OF MODIFIEDNAVIER-STOKES EQUATION

2021 ◽  
Vol 9 (5) ◽  
pp. 1127-1131
Author(s):  
Michael Oduor ◽  
Paul Oleche ◽  
Hagai Amakobe James
Keyword(s):  
Stokes Equation ◽  
Finite Volume ◽  
Numerical Scheme ◽  
Continuity Equation ◽  
Pressure Field ◽  
Control Volume ◽  
Staggered Grid ◽  
Navier Stokes ◽  
Pressure Equation ◽  
Navier Stokes Equation

This study has come up with a numerical scheme that arises from finite volume discretizationof Modified Navier-Stokes Equation.Modified Navier-Stokes Equation in the x-z axis was coupled with continuity equation to obtain the Pressure Equation. Using the pressure equation, pressure field can bedetermined in each control volume on a staggered grid.

Numerical Study of Different Closure Approaches for Prediction of Forced Convective Turbulent Cylindrical Cavity Flows

2016 ◽  
Vol 366 ◽  
pp. 166-181
Author(s):  
Elizaldo Domingues dos Santos ◽  
Marco Paulsen Rodrigues ◽  
Thiago Smith V.C. de Andrade ◽  
Liércio André Isoldi ◽  
Francis Henrique Ramos França ◽  
...  
Keyword(s):  
Turbulent Flows ◽  
Cylindrical Cavity ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Reynolds Stress Model ◽  
Navier Stokes ◽  
Cavity Flows ◽  
Thermal Fields ◽  
Convective Fluxes

The present work exhibits a numerical study comparing the fluid dynamic and thermal fields of turbulent, three-dimensional forced convective cylindrical cavity flows obtained with Large Eddy Simulation (LES) and Reynolds-Averaged Navier Stokes (RANS). In the latter approach, three different closure models are employed: Reynolds Stress Model (RSM), standard k – ε and standard k - ω. It is considered a three-dimensional, incompressible, turbulent fluid flow at the steady state with ReD = 22,000 and Pr = 0.71. The main purpose is to investigate whether discrepancies are noticed in time-averaged and statistics of turbulent flows between LES and RANS predictions. Differences in time-averaged and statistical fields can be important for evaluation of convective fluxes in turbulent flows and combined convective and radiative transfer in participant media, i.e., for study of Turbulence-Radiation Interactions (TRI). The spatially-filtered and time-averaged conservation equations of mass, momentum and energy are solved with the Finite Volume Method (FVM). Results showed that time-averaged and RMS thermal fields obtained with LES and RANS presented reasonable discrepancies in regions near the cavity surfaces, which affects the convective fluxes in this region. For the highest temperature region of the cavity (near its inlet) the predictions obtained with LES and RANS are similar, which can led to similar predictions in heat exchange when thermal radiation is taken into account in optically thin participant media. For optically thick media, where local differences increase their importance, the employment of RANS is not recommended.

Navier-Stokes Simulation of the Flow Around a Leading Edge Film-Cooled Turbine Blade Including the Interior Cooling System and Comparison With Experimental Data

1996 ◽  
Author(s):  
Dirk T. Vogel
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Turbine Blade ◽  
Cooling System ◽  
Three Dimensional ◽  
Leading Edge ◽  
Navier Stokes ◽  
Complex Flow ◽  
Three Dimensional Flow ◽  
Dimensional Flow

The three dimensional flow around an extensively investigated slot film cooled turbine blade is numerically investigated using a multi block finite volume Navier-Stokes solver. Three blowing rates are simulated including the whole geometry of the interior blade cooling system and slots. Due to the ejection at the blade leading edge and the geometry of the cooling slots a very complex turbulent three dimensional flow field is generated. The size and shape of the flow separation zones depending on the film cooling ejection is systematically investigated using several two-equation models, e.g. the standard and low Reynolds k–ε-Model of Lam and Bremhorst (1981) r[4], the extension of Kato/Launder (1993) [3] and the k–ω-Model of Wilcox (1991) [10], whereas the results of the standard k–ε-Model are presented. Experimental data obtained by Laser velocimetry, oil-flow pictures and pressure probes are used to understand the complex flow field and to validate the Navier-Stokes solver. The multi-block code applies a traditional Jameson type solver and an implicit solver using several spatial discretization schemes for the convective fluxes. The two-equation models are solved using an RED-BLACK implicit technique with first order spatial upwind discretization to guarantee stability.

Computational simulation of turbulent flows around a marine propeller by solving the partially averaged Navier–Stokes equation

2019 ◽  
Vol 233 (18) ◽  
pp. 6357-6366
Author(s):  
Woochan Seok ◽  
Sang Bong Lee ◽  
Shin Hyung Rhee
Keyword(s):  
Turbulent Flow ◽  
Reynolds Stress ◽  
Stokes Equation ◽  
Leading Edge ◽  
Reynolds Stress Model ◽  
Navier Stokes ◽  
Stress Model ◽  
Navier Stokes Equation ◽  
Local Flow ◽  
Reynolds Averaged Navier Stokes

This study concerns the characteristics of the partially averaged Navier–Stokes method for local flow analysis around a rotating propeller. Partially averaged Navier–Stokes, resolving crucial large-scale structures of turbulent flow at a given computational grid resolution, is a bridging turbulence closure model between the Reynolds-averaged Navier–Stokes equation and the direct numerical simulation. A detailed comparison between partially averaged Navier–Stokes and Reynolds-averaged Navier–Stokes models is made to achieve a better understanding of partially averaged Navier–Stokes characteristics for predicting the coherent structures in turbulent flow. The two-equation k-ω shear stress transport model and the seven-equation Reynolds stress model are selected for Reynolds-averaged Navier–Stokes computations. The problem of interest is the flow around a rotating KP505 propeller in open water conditions at an advance ratio of 0.7. Near the leading edge, the partially averaged Navier–Stokes results are similar to those of Reynolds stress model in terms of the vortical structures. Vorticity predicted by different turbulence models, however, shows significant differences. For a more detailed analysis, the velocity gradient constituting the vorticity is identified at the leading edge. It is proven that partially averaged Navier–Stokes is able to capture the anisotropic characteristics of the flow at the leading edge, where both the geometric and flow characteristics change abruptly.

Numerical Investigation of Contribution of Three Flow Conditioners in the Development and Establishment of Turbulent Flows

2010 ◽  
Author(s):  
Boualem Laribi ◽  
Pierre Wauters ◽  
Abdelkader Youcefi
Keyword(s):  
Turbulent Flows ◽  
Stokes Equations ◽  
Numerical Study ◽  
Tube Bundle ◽  
Three Dimensional ◽  
Perforated Plate ◽  
Reynolds Stress Model ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Out Of Plane

This numerical study is a comparative study of the development and establishment of turbulent flows through three flow conditioners namely Laws perforated plate, the Etoile and the tube bundle. They are installed in a circular pipe with a disturbance generated by a 90° double bend out of plane which causes a very strong swirl of the fluid. The analysis is done with the code Fluent in which the Navier-Stokes equations describe a three-dimensional incompressible flow with the Reynolds stress model (RSM) as a closure system. This article focuses on the effectiveness of the three packers to produce the condition of fully developed velocity profile. The results are compared to references profiles cited in the literature and experimental results. The flow is simulated with air at Reynolds number of 105 in 100mm pipe diameter. The velocity profiles are compared with the profile obtained by the universal law of power 1/7th.

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