scholarly journals Mathematical Modelling of Turbulent Combustion of Two-Phase Mixtures of Gas and Solid Particles with a Eulerian–Eulerian Approach: The Case of Hydrogen Combustion in the Presence of Graphite Particles

Mathematics ◽  
2021 ◽  
Vol 9 (17) ◽  
pp. 2017
Author(s):  
Francisco Nicolás-Pérez ◽  
F.J.S. Velasco ◽  
Ramón A. Otón-Martínez ◽  
José R. García-Cascales ◽  
Ahmed Bentaib ◽  
...  
Keyword(s):  
Turbulent Combustion ◽  
Stokes Equations ◽  
Hydrogen Combustion ◽  
Solid Particles ◽  
Detailed Chemical Kinetics ◽  
Chemical Kinetic Model ◽  
Combustion Dynamics ◽  
Low Concentration ◽  
Graphite Particles ◽  
Detailed Chemical

The numerical modelling of turbulent combustion of H2–air mixtures with solid graphite particles is a challenging and key issue in many industrial problems including nuclear safety. This study presents a Eulerian–Eulerian model based on the resolution of the Navier–Stokes equations via large eddy simulation (LES) coupled with a system of ordinary differential equations (ODEs) of the detailed chemical kinetics to simulate the combustion of mixtures of gases and particles. The model was applied to predict the transient evolution of turbulent combustion sequences of mixtures of hydrogen, air and graphite particles under low concentration conditions. When applied to simulate lab-scale combustion experiments, the results showed a good agreement between experimental and numerical data using a detailed chemical kinetic model. Moreover, the model was able to predict some key experimental tendencies and revealed that the presence of a low concentration of graphite particles (~96 g/m3) in the scenario influenced the hydrogen combustion dynamics for mixtures of 20% (in volume) of hydrogen in air. Under these conditions, pressure levels reached at the walls of the sphere were increased and the combustion time was shortened. The results also showed the viability of using this kind of a model for obtaining global combustion parameters such as wall pressure evolution with time.

Validation of Methods for Calculating Hydrogen Combustion in a Supersonic Model Air Flow Using the Experimental Data of Beach — Evans — Schexnayder

2019 ◽  
pp. 36-45
Author(s):  
N.V. Kukshinov ◽  
S.N. Batura ◽  
M.S. Frantsuzov
Keyword(s):  
Chemical Kinetics ◽  
Stokes Equations ◽  
Turbulence Models ◽  
Fuel Mixture ◽  
Navier Stokes ◽  
Detailed Chemical Kinetics ◽  
Navier Stokes Equations ◽  
Kinetic Mechanisms ◽  
Relative Errors ◽  
Detailed Chemical

This paper deals with numerical simulation of combustion of a hydrogen-air mixture in a supersonic flow. The simulation is based on solving the complete system of Navier-Stokes equations with closure using the turbulence model and detailed chemical kinetics. The mixing and combustion of a hydrogen-air fuel mixture is considered in the experimental formulation of Beach-Evans-Schexnayder. The effect of various kinetic mechanisms, turbulence models, TCI models, and boundary conditions on the solution is studied qualitatively and quantitatively. The relative errors of mass concentration of water for control sections are determined, and the methods’ boundaries are shown. Conclusions are drawn on the influence of turbulent mixing mechanisms and chemical kinetics on the combustion of hydrogen.

scholarly journals Application of a Micro-/Macro-Mixing Two Reactor Model to a Single-Cup Low-Emissions Combustor

1998 ◽  
Author(s):  
T. J. Held ◽  
H. C. Mongia ◽  
J. H. Tonouchi
Keyword(s):  
Gas Turbine ◽  
Preliminary Design ◽  
Gas Turbine Combustor ◽  
Detailed Chemical Kinetics ◽  
Reactor Model ◽  
Combustion Dynamics ◽  
Design Variables ◽  
Successful Design ◽  
Dynamics Simulations ◽  
Detailed Chemical

During the preliminary design and analysis phase of a gas turbine combustor, trade studies of the effects of design variables on emissions and operability are necessary to ensure a successful design. Due to the considerable resources required for full computational combustion dynamics simulations, simplified design tools are required for rapid analysis of a large number of design variable combinations. In a previous paper, a semi-analytical model of a gas turbine combustor was described (Tonouchi, et al., 1997). The model employs a gas particle Monte Carlo technique to simulate the effects of finite-rate micro- and macro-mixing, including full detailed chemical kinetics (Bowman, et al., 1997). Initial model validation work focused on emissions calculations for conventional rich dome combustors. This work presents NOx and CO emissions calculations for a single-cup natural gas-fired dry low emissions (DUE) combustor, and comparison to experimental data. The effect of parametric variation of the micro- and macro-mixing model constants, assigned volumes of the primary and secondary zones, and inlet unmixedness on the results are also presented.

Numerical CFD evaluation of a flameless burner using detailed chemical kinetics

2017 ◽  
Author(s):  
Marco Antonio Nascimento ◽  
Lucilene Oliveria Rodrigues ◽  
Fagner Luis Goulart Dias
Keyword(s):  
Chemical Kinetics ◽  
Detailed Chemical Kinetics ◽  
Flameless Burner ◽  
Detailed Chemical

PARALLEL SOLVER FOR THE SIMULATIONS OF DETONATION WAVES ON UNSTRUCTURED GRIDS

2020 ◽  
Author(s):  
A. I. Lopato ◽  
◽  
A. G. Eremenko ◽  
Keyword(s):  
Chemical Kinetics ◽  
Numerical Scheme ◽  
Unstructured Grids ◽  
Numerical Study ◽  
Numerical Approach ◽  
Detonation Waves ◽  
Detailed Chemical Kinetics ◽  
Parallel Solver ◽  
Further Development ◽  
Detailed Chemical

Recently, we developed a numerical approach for the simulation of detonation waves on fully unstructured grids and applied it to the numerical study of the mechanisms of detonation initiation in multifocusing systems. Current work is devoted to further development of our numerical approach, namely, parallelization of the numerical scheme and introduction of more comprehensive detailed chemical kinetics scheme.

Impacts of Dilution on Hydrogen Combustion Characteristics and NOx Emissions

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
P. R. Resende ◽  
Alexandre Afonso ◽  
Carlos Pinho ◽  
Mohsen Ayoobi
Keyword(s):  
Flame Stabilization ◽  
Combustion Characteristics ◽  
Operating Conditions ◽  
Nox Emissions ◽  
Detailed Chemical Kinetics ◽  
Portable Power ◽  
Small Scales ◽  
Potential Applications ◽  
Flame Behavior ◽  
Detailed Chemical

Combustion characteristics at small scales have been studied continuously due to the potential applications in portable power devices. It is known that heat release impacts at small scales result in different flame behavior as compared to conventional scales. The impacts of geometry, stoichiometry, flow rates, wall temperatures, etc., are widely studied in the literature. However, dilution impacts still need to be further studied due to its important role on controlling the flame behavior and subsequent pollutants emissions at these scales. In this work, premixed hydrogen/air combustion is simulated at an axis-symmetric microchannel (with diameter D = 0.8 mm and length L = 10 mm), where detailed chemical kinetics are implemented in simulations (32 species and 173 reactions). The heat transfer on the wall is considered by imposing a hyperbolic temperature profile on the wall, where the wall temperature increases from 300 K at the inlet to 1300 K at the outlet. With this setup, a range of equivalence ratios including a typical fuel-lean regime (ϕ = 0.7), stoichiometric regime (ϕ = 1.0), and two cases at an ultra-rich regime (ϕ = 2.0 and ϕ = 3.0) are investigated. For each equivalence ratio, excess dilution (using N2) is introduced to the mixture, and its impact is compared with other cases. With that, the impacts of dilution variations on the combustion characteristics of premixed hydrogen/air are investigated for different equivalence ratios. More specifically, several incidents such as flame dynamics, flame stabilization, extinctions, and NOx emissions are studied for the aforementioned operating conditions.

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