Turbulent combustion modelling of a confined premixed jet flame including heat loss effects using tabulated chemistry

When operating under lean fuel–air conditions, flame flashback is an operational safety issue in stationary gas turbines. In particular, with the increased use of hydrogen, the propagation of the flame through the boundary layers into the mixing section becomes feasible. Typically, these mixing regions are not designed to hold a high-temperature flame and can lead to catastrophic failure of the gas turbine. Flame flashback along the boundary layers is a competition between chemical reactions in a turbulent flow, where fuel and air are incompletely mixed, and heat loss to the wall that promotes flame quenching. The focus of this work is to develop a comprehensive simulation approach to model boundary layer flashback, accounting for fuel–air stratification and wall heat loss. A large eddy simulation (LES) based framework is used, along with a tabulation-based combustion model. Different approaches to tabulation and the effect of wall heat loss are studied. An experimental flashback configuration is used to understand the predictive accuracy of the models. It is shown that diffusion-flame-based tabulation methods are better suited due to the flashback occurring in relatively low-strain and lean fuel–air mixtures. Further, the flashback is promoted by the formation of features such as flame tongues, which induce negative velocity separated boundary layer flow that promotes upstream flame motion. The wall heat loss alters the strength of these separated flows, which in turn affects the flashback propensity. Comparisons with experimental data for both non-reacting cases that quantify fuel–air mixing and reacting flashback cases are used to demonstrate predictive accuracy.

Download Full-text

Subgrid Linear Eddy Mixing and Combustion Modelling of a Turbulent Nonpremixed Piloted Jet Flame

Flow Turbulence and Combustion ◽

10.1007/s10494-011-9371-y ◽

2011 ◽

Vol 89 (2) ◽

pp. 295-309 ◽

Cited By ~ 8

Author(s):

José Salvador Ochoa ◽

Alberto Sánchez-Insa ◽

Norberto Fueyo

Keyword(s):

Jet Flame ◽

Combustion Modelling ◽

Turbulent Nonpremixed

Download Full-text

Simulation of Methanol-Air Two-Phase Flames Using Various Turbulent Combustion Models

Volume 2: Combustion, Fuels and Emissions ◽

10.1115/gt2009-59344 ◽

2009 ◽

Author(s):

F. Wang ◽

Y. Huang ◽

Y. Z. Wu

Keyword(s):

Experimental Data ◽

Turbulent Combustion ◽

Turbulent Jet ◽

Combustion Model ◽

Air Flow Rate ◽

Two Phase ◽

Jet Flame ◽

Combustion Simulation ◽

Turbulent Combustion Model ◽

Turbulent Models

Though fossil fuel is running out, liquid fuels nowadays still provide the most energy used by industrial furnaces, automotive and aero engines. How to predict a two-phase turbulent combustion flame is still a big problem to designers. Generally, the liquid fuel is sprayed and mixed with oxygen, and the flame characteristics depends on the fuel atomization, the fuel droplet spatial distribution, and its interaction with the turbulent oxidizer flow field: turbulent heat, mass and momentum transfer, complicated chemical kinetics, and turbulent-chemistry interaction. Turbulent combustion model is a key point for the two phase combustion simulation. For its short time consuming, Reynolds Averaged Navier Stokes (RANS) method nowadays still is the major tool for gas turbine chamber (GTC) designers, but there is not a universal method in RANS GTC spray combustion simulation at present especially for the two-phase turbulent combustion. The Eddy-Break-Up turbulent combustion model (EBU), Eddy Dissipation Concept turbulent combustion model (EDC), steady Laminar Flame-let turbulent combustion Model (LFM) and the Composition PDF transport turbulent combustion model (CPDF) are all widely used models. In this paper, these four turbulent models are used to simulate a methane-air turbulent jet flame measured by Sandia Lab first, then three methanol-air two-phase turbulent flames, in order to know the ability of these turbulent models. In the gas turbulent jet flame simulation, the result of LFM model and CPDF model are in better agreement with the experimental data than those of the EBU and the EDC models’ results. The reason is that the EBU model and EDC model are overestimated the effect of turbulent. In the three different cases of the two phase combustion simulation, CPDF is the best. The prediction ability of the other three models is different in different cases. The EDC predictions are closer to the experimental data when the air flow rate value is lower, whereas the LFM predictions are better when the air flow rate value is higher.

Download Full-text

Evaluation of different turbulent combustion models based on tabulated chemistry using DNS of heterogeneous mixtures

Combustion Theory and Modelling ◽

10.1080/13647830.2016.1247214 ◽

2016 ◽

Vol 21 (3) ◽

pp. 440-465 ◽

Cited By ~ 3

Author(s):

Stephane Chevillard ◽

Jean-Baptiste Michel ◽

Cecile Pera ◽

Julien Reveillon

Keyword(s):

Turbulent Combustion ◽

Combustion Models ◽

Tabulated Chemistry

Download Full-text

Gradient trajectory analysis in a Jet flow for turbulent combustion modelling

Journal of Turbulence ◽

10.1080/14685248.2012.747688 ◽

2013 ◽

Vol 14 (1) ◽

pp. 147-164 ◽

Cited By ~ 12

Author(s):

M. Gampert ◽

P. Schaefer ◽

V. Narayanaswamy ◽

N. Peters

Keyword(s):

Turbulent Combustion ◽

Trajectory Analysis ◽

Jet Flow ◽

Combustion Modelling

Download Full-text

A simulation with a “cellular automaton” for turbulent combustion modelling

Symposium (International) on Combustion ◽

10.1016/s0082-0784(89)80064-5 ◽

1989 ◽

Vol 22 (1) ◽

pp. 569-577 ◽

Cited By ~ 16

Author(s):

R. Saïd ◽

R. Borghi

Keyword(s):

Cellular Automaton ◽

Turbulent Combustion ◽

Combustion Modelling

Download Full-text

Lean-Blow-Out Simulation of Natural Gas Fueled, Premixed Turbulent Jet Flame Arrays With LES and FGM-Modeling

10.1115/gt2021-58938 ◽

2021 ◽

Author(s):

Alexander Schwagerus ◽

Peter Habisreuther ◽

Nikolaos Zarzalis

Keyword(s):

Turbulence Modeling ◽

Operating Conditions ◽

Jet Flames ◽

General Applicability ◽

Jet Flame ◽

Lean Blowout ◽

Eddy Simulation ◽

Stable Conditions ◽

Tabulated Chemistry ◽

The Matrix

Abstract To ensure compliance with stricter regulations on exhaust gas emissions, new industrial burner concepts are being investigated. One of these concepts is the matrix burner, consisting of an array of premixed, non-swirling jet flames. For the design of such burners, the prediction of fundamental burner properties is mandatory. One of these essential quantities is the lean blowout limit (LBO), which has already been investigated experimentally. This study investigates the possibility of numerical LBO prediction using a tabulated chemistry approach in combination with Large-Eddy-Simulation turbulence modeling. In contrast to conventional swirl burners, the numerical description of blowout events of multi jet flames has not yet been studied in detail. Lean blowout simulations have therefore been conducted for multiple nozzle variants, varying in their diameter and global dump ratio for a variety of operating conditions, showing their general applicability. A procedure to induce LBO is introduced where a stepwise increase in total mass flow is applied. LBO is determined based on the temporal progress of the mean reaction rate. A comparison with measurements shows good agreement and demonstrates that the procedure developed here is an efficient way to predict LBO values. Further investigations focused on the flame behavior when approaching LBO. The flame shape shows a drastic change from single jet flames (stable conditions) to a joint conical flame approaching LBO, which increases in length for increasing inlet velocity, showing the importance of jet interaction at LBO.

Download Full-text

Modelling Turbulent Combustion in a Non-Adiabatic CO/H2 Flame Using Reaction Progress Variables

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations ◽

10.1115/96-gt-184 ◽

1996 ◽

Author(s):

Jim B. W. Kok ◽

Jurgen J. J. Louis

Keyword(s):

Gas Turbine ◽

Heat Loss ◽

Diffusion Flame ◽

Turbulent Combustion ◽

Heat Losses ◽

Intermediate Species ◽

Reaction Progress ◽

Fuel Concentration ◽

Fuel Mixing ◽

Loss Effect

A model is presented for the turbulent combustion of CO/H2-air mixtures at gas turbine conditions. The model takes account of heat losses. The conversion of CO to CO2 and of H2 to H2O, as well as the non-equilibrium intermediate species concentrations are determined by two reaction progress variables and two other scalar variables. The initially available fuel concentration is expressed by a fuel mixing variable. The heat loss effect on the enthalpy is described by a scaled enthalpy variable. The modelled turbulent source terms in the transport equations for the scalar variables are discussed. Three cases of a turbulent CO/H2 diffusion flame with heat loss and chemical super-equilibrium of intermediate species are presented.

Download Full-text