The Influence of In Situ Reheat on Turbine-Combustor Performance

2004 ◽  
Vol 128 (3) ◽  
pp. 560-572 ◽  
Author(s):  
Steven Chambers ◽  
Horia Flitan ◽  
Paul Cizmas ◽  
Dennis Bachovchin ◽  
Thomas Lippert ◽  
...  
Keyword(s):  
Fuel Injection ◽  
Stokes Equations ◽  
Species Conservation ◽  
Navier Stokes ◽  
Combustion Model ◽  
Navier Stokes Equations ◽  
Blade Loading ◽  
Combustion Gases ◽  
Injection Parameters

This paper presents a numerical and experimental investigation of the in situ reheat necessary for the development of a turbine-combustor. The flow and combustion were modeled by the Reynolds-averaged Navier-Stokes equations coupled with the species conservation equations. The chemistry model used herein was a two-step, global, finite rate combustion model for methane and combustion gases. A numerical simulation was used to investigate the validity of the combustion model by comparing the numerical results against experimental data obtained for an isolated vane with fuel injection at its trailing edge. The numerical investigation was then used to explore the unsteady transport phenomena in a four-stage turbine-combustor. In situ reheat simulations investigated the influence of various fuel injection parameters on power increase, airfoil temperature variation, and turbine blade loading. The in situ reheat decreased the power of the first stage, but increased more the power of the following stages, such that the power of the turbine increased between 2.8% and 5.1%, depending on the parameters of the fuel injection. The largest blade excitation in the turbine-combustor corresponded to the fourth-stage rotor, with or without combustion. In all cases analyzed, the highest excitation corresponded to the first blade passing frequency.

The Influence of In Situ Reheat on Turbine-Combustor Performance

2004 ◽  
Author(s):  
Steven Chambers ◽  
Horia Flitan ◽  
Paul Cizmas ◽  
Dennis Bachovchin ◽  
Thomas Lippert ◽  
...  
Keyword(s):  
Fuel Injection ◽  
Stokes Equations ◽  
Species Conservation ◽  
Navier Stokes ◽  
Combustion Model ◽  
Navier Stokes Equations ◽  
Blade Loading ◽  
Combustion Gases ◽  
Injection Parameters

This paper presents a numerical and experimental investigation of the in situ reheat necessary for the development of a turbine-combustor. The flow and combustion are modeled by the Reynolds-averaged Navier-Stokes equations coupled with the species conservation equations. The chemistry model used herein is a two-step, global, finite rate combustion model for methane and combustion gases. A numerical simulation has been used to investigate the validity of the combustion model by comparing the numerical results against experimental data obtained for an isolated vane with fuel injection at its trailing edge. The numerical investigation has then been used to explore the unsteady transport phenomena in a four-stage turbine-combustor. In situ reheat simulations investigated the influence of various fuel injection parameters on power increase, airfoil temperature variation and turbine blade loading.

Preliminary Simulation of a 3D Turbine Stage with In Situ Combustion

2015 ◽  
Vol 772 ◽  
pp. 103-107 ◽  
Author(s):  
Sterian Danaila ◽  
Dragoș Isvoranu ◽  
Constantin Leventiu
Keyword(s):  
Fuel Injection ◽  
Stokes Equations ◽  
Transport Model ◽  
Salient Feature ◽  
Navier Stokes ◽  
Combustion Model ◽  
Turbine Stage ◽  
Shear Stress Transport Model ◽  
Rotor Stator Interaction

This paper presents the preliminary results of the numerical simulation of flow and combustion in a one stage turbine combustor (turbine stage in situ combustion). The main purpose of the simulation is to assess the stability of the in situ combustion with respect to the unsteadiness induced by the rotor-stator interaction. Apart from previous attempts, the salient feature of this CFD approach is the new fuel injection concept that consisting of a perforated pipe placed at mid-pitch in the stator row passage. The flow and combustion are modelled by the Reynolds-averaged Navier-Stokes equations coupled with the species transport equations. The chemistry model used herein is a two-step, global, finite rate combustion model while the turbulence model is the shear stress transport model. The chemistry turbulence interaction is described in terms of eddy dissipation concept.

scholarly journals Numerical Simulation of Combustion and Rotor-Stator Interaction in a Turbine Combustor

2003 ◽  
Vol 9 (5) ◽  
pp. 363-374 ◽  
Author(s):  
Dragos D. Isvoranu ◽  
Paul G. A. Cizmas
Keyword(s):  
Numerical Algorithm ◽  
Stokes Equations ◽  
Species Conservation ◽  
Finite Difference Approximation ◽  
Navier Stokes ◽  
Difference Approximation ◽  
Combustion Model ◽  
Combustion Gases ◽  
Fully Implicit ◽  
Correction Technique

This article presents the development of a numerical algorithm for the computation of flow and combustion in a turbine combustor. The flow and combustion are modeled by the Reynolds-averaged Navier-Stokes equations coupled with the species-conservation equations. The chemistry model used herein is a two-step, global, finite-rate combustion model for methane and combustion gases. The governing equations are written in the strong conservation form and solved using a fully implicit, finite-difference approximation. The gas dynamics and chemistry equations are fully decoupled. A correction technique has been developed to enforce the conservation of mass fractions. The numerical algorithm developed herein has been used to investigate the flow and combustion in a one-stage turbine combustor.

Unsteady Vortices and Blade Loading in a High-Pressure Turbine

2009 ◽  
Author(s):  
Dongil Chang ◽  
Stavros Tavoularis
Keyword(s):  
High Pressure ◽  
Stokes Equations ◽  
Pressure Fluctuations ◽  
Rotor Blades ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Time Resolved ◽  
Blade Loading ◽  
Pressure Losses ◽  
Horseshoe Vortices

Unsteady flow in a transonic, single-stage, high-pressure, axial turbine has been investigated numerically by solving the URANS (Unsteady Reynolds-Averaged Navier-Stokes) equations with the SST (Shear Stress Transport) turbulence model. Interest has focused on the identification and effects of the quasi-stationary vane and blade horseshoe vortices, vane and blade passage vortices, vane and blade trailing edge vortices, and blade tip leakage vortices. Moreover, two types of unsteady vortices, not discussed explicitly in the previous literature, have been identified and termed “axial gap vortices” and “crown vortices”. All vortices have been clearly and distinctly identified using a modified form of the Q criterion, which is less sensitive to the set threshold than the original version. The use of pathlines and iso-contours of static pressure, axial vorticity and entropy has been further exploited to distinguish the different types of vortices from each other and to mark their senses of rotation and strengths. The influence of these vortices on the entropy distribution at the outlet has been investigated. The observed high total pressure losses in the turbine at blade midspan have been connected to the action of passage vortices. The formation and disappearance processes of unsteady vortices located in the spacing between the stator and the rotor have been time-resolved. These vortices are roughly aligned with the leading edges of the rotor blades and their existence depends on the position of the blade with respect to the upstream vanes. In addition, the present study focuses on the unsteady blade loading that influences vibratory stresses. Contours of the time-dependent surface pressure on the rotor blade have demonstrated the presence of large pressure fluctuations near the front of the blade suction sides; these pressure fluctuations have been associated with the periodic passages of shock waves originating at the vane trailing edges.

Prediction of Ring Crevice Hydrocarbons Depending on Some Engine Parameters

2004 ◽  
Author(s):  
A. Murat Yildirim ◽  
Zafer Gu¨l
Keyword(s):  
Engine Speed ◽  
Stokes Equations ◽  
Ignition Time ◽  
Phenomenological Approach ◽  
Solution Procedure ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Combustion Gases ◽  
Crank Angle ◽  
Valve Overlap

The model consists of three major submodels. First is prediction of time-varying composition of combustion gases, second is modelling the release of the ring crevice HC’s during late expansion and exhaust stroke and the last one is a simple phenomenological approach for calculation of temperature variation with crank angle. Valve overlap period is excluded in the solution. It is necessary for 2d-solution. Continuity and Navier-Stokes equations are solved. But instead of energy equation, above mentioned phenomenological submodel is introduced for calculation of temperature. Oil film HC’s and postflame oxidation are excluded, as for the last, solution procedure enhances the period after which in cylinder oxidation ceases. Result are presented at the extend limited counterparts allow, due to the lack of common parameters adapted in different studies amongst plenty of them. HC versus engine speed, inlet pressure, equivalence ratio, compression ratio, ignition time and crank position at which combustion ends are plotted.

Numerical Simulation of a Ceramic Furnace Burner - Capacity of Turbulent and Radiation Models

2009 ◽  
Vol 283-286 ◽  
pp. 243-249
Author(s):  
Anouar Souid ◽  
Wassim Kriaa ◽  
Hatem Mhiri ◽  
Georges Le Palec ◽  
Philippe Bournot
Keyword(s):  
Stokes Equations ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Modern Society ◽  
Navier Stokes ◽  
Combustion Model ◽  
Radiation Model ◽  
Navier Stokes Equations ◽  
Commercial Code ◽  
Furnace Burner

We intend in this work to model an industrial burner replica of the ceramic tunnel furnace of the Ceramics Modern Society (SOMOCER, TUNISIA). This study aims to evaluate the ability of turbulence and radiation models to predict the dynamics and heat transfer fields. The study is conducted by means of numerical simulations in presence of a reactive flow using the commercial code FLUENT. The 3D Navier-Stokes equations and four species transport equations are solved with the eddy-dissipation (ED) combustion model. We use three turbulence models (k- standard, k- RNG, and RSM) and two radiation models (DTRM and DO). The obtained results demonstrate that the k- standard turbulence model is unable to predict the flow characteristics whereas; the k- RNG and RSM models give a satisfying agreement with the experiments. Suitable results are provided by the DTRM radiation model; whereas, those given by the DO model can be improved.

scholarly journals Numerical simulation of the shock-wave structure of a reacting hydrogen-air mixture in a model channel

2021 ◽  
Vol 2057 (1) ◽  
pp. 012067
Author(s):  
N V Kukshinov ◽  
D L Mamyshev
Keyword(s):  
Numerical Simulation ◽  
Stokes Equations ◽  
Wave Structure ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Combustion Efficiency ◽  
Navier Stokes ◽  
Combustion Model ◽  
Navier Stokes Equations ◽  
Model Channel

Abstract The paper deals with the results of numerical simulation of hydrogen-air combustion in a supersonic flow of a model channel of a known configuration, investigated in the “HyShot” project. The simulation is carried out by solving the Favre-averaged system of Navier-Stokes equations, supplemented by a turbulence and combustion model and a chemical-kinetic mechanism. The influence of different throat heights on the performance of the model due to combustion efficiency and total pressure loss coefficients is investigated.

Numerical Simulation of Transonic Fan Flutter With 3D N-S CFD Code

2008 ◽  
Author(s):  
Mizuho Aotsuka ◽  
Naoki Tsuchiya ◽  
Yasuo Horiguchi ◽  
Osamu Nozaki ◽  
Kazuomi Yamamoto
Keyword(s):  
Shock Wave ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Suction Surface ◽  
Navier Stokes Equations ◽  
Blade Loading ◽  
Flow Solver ◽  
Flutter Boundary ◽  
Transonic Fan ◽  
Volume Method

This paper describes the calculation of transonic stall flutter of a fan. A new CFD code has been developed and validated. The code is an unsteady 3D multi-block flow solver. The Reynolds-Averaged Navier-Stokes equations are solved using a finite volume method with Spallart-Allmaras 1 equation turbulence model. A grid deforming system is applied, so the new code is capable of simulating an oscillating blade row. This grid deforming system produces less grid distortion and the code has robustness for a blade oscillating calculation. The code has validated on an IHI’s research transonic fan rig test, and the result was in good agreement with the test data in the prediction of the flutter boundary. In the rig test at part-speed condition, stall-side flutter was experienced. In that condition, the inlet relative Mach number in the tip region is about unity. The aerodynamic work by the CFD at the near flutter condition is positive, which means that the flutter characteristic is unstable, while at other conditions the aerodynamic work is negative. The aerodynamic work increases rapidly just before the zero damping point with the increase of the blade loading. From the detailed CFD result, the shock wave on the suction surface contributes to the excitement of the blade oscillation, and the aerodynamic work of the shock wave has large value at the flutter condition.

scholarly journals The Effect of Bluff Body Shape on Flame Stability in a Non-Premixed Hydrogen-Methan-Air Mixture Combustion

2021 ◽  
Vol 45 (5) ◽  
pp. 385-392
Author(s):  
Fatma Zohra Khelladi ◽  
Mounir Alliche ◽  
Redha Rebhi ◽  
Giulio Lorenzini ◽  
Hijaz Ahmad ◽  
...  
Keyword(s):  
Diffusion Flame ◽  
Bluff Body ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Combustion Model ◽  
Cylindrical Shape ◽  
Navier Stokes Equations ◽  
Ansys Cfx ◽  
The Stability ◽  
Air Diffusion

The goal of this study, which focuses on the effect of the bluff-body form on the flame’s stability, is to contribute to the study of the stability of a CH4-H2-Air diffusion flame. It is, in fact, a numerical simulation of a diffusion flame CH4-H2-Air stabilized by a bluff body in three different shapes: cylindrical, semi-spherical and conical. The equations governing turbulent reactive flow are solved using the Ansys CFX program (Navier Stokes equations averaged in sense of Favre). The k-ε model simulates turbulence. For combustion, a mixed EDM/FRC (Finite Rate Combustion) model is utilized. The results of the analysis of temperature profiles, CO2 concentrations, and velocity in axial sections very close to the injector are satisfactory: they meet the criteria of stability, high temperature at a lower speed, and more stable in the case of a cylindrical shape than in the other two cases.

Advances in Microscale and Nanoscale Mechanisms of Electrophoretic Deposition in Aqueous Media

2015 ◽  
Vol 654 ◽  
pp. 23-28
Author(s):  
Guido Falk ◽  
Alexander Nold ◽  
Birgit Wiegand
Keyword(s):  
Electrophoretic Deposition ◽  
Stokes Equations ◽  
Aqueous Media ◽  
Deposition Process ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Field Gradients ◽  
Element Approach ◽  
Experimental Findings

The processing of ceramic thick and thin films, nano- and micro-scaled ceramic structures as well as bulk ceramics of high quality and precise dimensions under electrophoretic boundary conditions requires a full understanding of the dynamics of relevant interfacial mechanisms and interactions of colloidal phases at the nano- and micro-scale. Recent findings and latest insights on the importance of electrokinetic and electrohydrodynamic interfacial processes for membrane electrophoretic depositon in aqueous media are summarised. In this context, the paper addresses the fundamental importance of surficial charge heterogeneities, electric double layer instabilities, electrokinetically induced micro-vortex dynamics, as well as lateral and medial effective electrical field gradients. These phenomena are evaluated in terms of reasonable correlations and mechanistic coincidences of general EPD deposition principles. The experimental results are based on potentiometry, in-situ videomicroscopy, high-resolution as well as secondary electron microscopy. A numerical method for the simulation of the electrophoretic deposition process is suggested based on a multiphysical Finite Element approach given by Nernst-Planck, Poisson- and Navier-Stokes equations. The results of the simulations provide adequate agreement with experimental findings.

Sign in / Sign up

Export Citation Format

Share Document