Perfectly stirred reactor model to evaluate extinction of diffusion flame

2015 ◽  
Vol 162 (10) ◽  
pp. 3622-3631 ◽  
Author(s):  
A. Yu. Snegirev
Keyword(s):  
Diffusion Flame ◽  
Reactor Model ◽  
Stirred Reactor

A Multidisciplinary Approach for the Comprehensive Assessment of Integrated Rotorcraft–Powerplant Systems at Mission Level

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Ioannis Goulos ◽  
Fakhre Ali ◽  
Konstantinos Tzanidakis ◽  
Vassilios Pachidis ◽  
Roberto d'Ippolito
Keyword(s):  
Environmental Impact ◽  
Fuel Consumption ◽  
Comprehensive Assessment ◽  
Pollutant Emissions ◽  
Operational Performance ◽  
Civil Aviation ◽  
Accurate Estimation ◽  
Nox Emissions ◽  
Reactor Model ◽  
Stirred Reactor

This paper presents an integrated methodology for the comprehensive assessment of combined rotorcraft–powerplant systems at mission level. Analytical evaluation of existing and conceptual designs is carried out in terms of operational performance and environmental impact. The proposed approach comprises a wide-range of individual modeling theories applicable to rotorcraft flight dynamics and gas turbine engine performance. A novel, physics-based, stirred reactor model is employed for the rapid estimation of nitrogen oxides (NOx) emissions. The individual mathematical models are implemented within an elaborate numerical procedure, solving for total mission fuel consumption and associated pollutant emissions. The combined approach is applied to the comprehensive analysis of a reference twin-engine light (TEL) aircraft modeled after the Eurocopter Bo 105 helicopter, operating on representative mission scenarios. Extensive comparisons with flight test data are carried out and presented in terms of main rotor trim control angles and power requirements, along with general flight performance charts including payload-range diagrams. Predictions of total mission fuel consumption and NOx emissions are compared with estimated values provided by the Swiss Federal Office of Civil Aviation (FOCA). Good agreement is exhibited between predictions made with the physics-based stirred reactor model and experimentally measured values of NOx emission indices. The obtained results suggest that the production rates of NOx pollutant emissions are predominantly influenced by the behavior of total air inlet pressure upstream of the combustion chamber, which is affected by the employed operational procedures and the time-dependent all-up mass (AUM) of the aircraft. It is demonstrated that accurate estimation of on-board fuel supplies ahead of flight is key to improving fuel economy as well as reducing environmental impact. The proposed methodology essentially constitutes an enabling technology for the comprehensive assessment of existing and conceptual rotorcraft–powerplant systems, in terms of operational performance and environmental impact.

Coherent Flame Model to Predict Formation Pollutants in Turbulent Premixed Flame

2010 ◽  
Author(s):  
Abdelhalim Bentebbiche ◽  
Denis Veynante
Keyword(s):  
Kinetic Scheme ◽  
Turbulent Flames ◽  
Premixed Flame ◽  
Reactive Flow ◽  
Reactor Model ◽  
Turbulent Premixed Flame ◽  
No Formation ◽  
Stirred Reactor ◽  
Good Issue ◽  
Turbulent Premixed

The objective of this work is to analyze and to model the turbulent flames in the context of coherent flame model. We present a detailed description of equations and the flamelet regimes in turbulent premixed flame. A surface density models proposed here represents a good issue for numerical simulation. Extension of coherent flame model and homogenous stilled reactor model is proposed to consider the dynamics behavior of flame and pollutants formation. From the results of this work it is concluded that the coherent flame model allows surpassing difficulties of the turbulent reactive flow modeling. Calculations based on a semi-global kinetic scheme and flamelet formulation combined with a well stirred reactor analysis of the burnt gases are used and provided reasonably accurate values of CO and NO formation. Also, we have observed that CO is formed near the reaction zone (front flame) but emission of CO2, H2O and NO are formed in the hot gases.

Micro-Kinetic Study of Reduction of NO on Pt Group Catalysts

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Dinesh B Mantri ◽  
Preeti Aghalayam
Keyword(s):  
Reaction Mechanism ◽  
Surface Coverage ◽  
No Reduction ◽  
Catalytic Reduction ◽  
Effect Of Temperature ◽  
Exponential Potential ◽  
Reactor Model ◽  
Reduction Activity ◽  
Stirred Reactor ◽  
High Durability

Catalytic reduction using CO has significant potential for the control of NOx using Pt group catalysts as CO is already present in the exhausts and Pt group catalysts have high durability in the presence of SO2 and H2O. Different reaction mechanisms are given in the literature for this reaction based on NO dissociation, -NCO formation and so on, but the exact reaction mechanism capable of capturing experimentally observed features is as yet unavailable. To determine the kinetics and reaction mechanism, we propose here an elementary reaction mechanism based on NO dissociation applicable to Pt group catalysts and simulated with CHEMKIN 4.0.2 using single and multiple PSR (Perfectly Stirred Reactor) model. The activation energies of the elementary steps are found from the Unity Bond Index-Quadratic Exponential Potential (UBI-QEP) method. Excellent agreement between literature experiments and our simulation results are observed for the NO-CO reaction on Pt and Rh catalysts and for the NO-CO-O2 reaction on Ir catalyst. The effect of temperature on the NO reduction activity is captured well by the model. Additionally the simulations can also point towards importance of particular reactions, selectivity to N2, effects of surface coverage, effects of residence time and catalytic surface area on NO reduction.

scholarly journals Modeling of kerosene combustion under fuel-rich conditions

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771138 ◽  
Author(s):  
Eunhye Song ◽  
Juhun Song
Keyword(s):  
Flame Temperature ◽  
Chemical Species ◽  
Oxidation Mechanism ◽  
Thermodynamic Characteristics ◽  
Stable Operation ◽  
Gas Temperature ◽  
Gas Generator ◽  
Reactor Model ◽  
Operation Conditions ◽  
Stirred Reactor

The turbo-pump and turbine are driven by liquid fuel fed into a gas generator, where the fuel is oxidized with a liquid oxidizing agent. For stable operation of the turbine, the combustion temperature of the gas generator must be maintained below 1000 K. The thermodynamic characteristics of kerosene oxidation in the gas generator must be understood to optimize the design and operation conditions of the liquid-fueled rocket engine system. Herein, the 3-species surrogate mixture model for kerosene was selected, and the detailed Dagaut’s kerosene oxidation mechanism consisting of 225 chemical species and 1800 reversible chemical reactions was utilized. The exit gas temperature and product gas composition in the gas generator under fuel-rich conditions were simulated by applying the perfectly stirred reactor model. The perfectly stirred reactor model was used in combination with the liquid spray model for evaporation of the droplets and the two-temperature model for evaluation of the flame temperature separately from the locally averaged reactor temperature. The theoretical prediction of the gas species fraction and soot yield could be improved by applying the tar cracking mechanism, where the reaction characteristics under high temperature were taken into account.

scholarly journals Large Eddy simulation of a supersonic lifted hydrogen flame with perfectly stirred reactor model

2021 ◽  
Vol 230 ◽  
pp. 111441
Author(s):  
Majie Zhao ◽  
Zhi X. Chen ◽  
Huangwei Zhang ◽  
Nedunchezhian Swaminathan
Keyword(s):  
Large Eddy Simulation ◽  
Reactor Model ◽  
Eddy Simulation ◽  
Stirred Reactor ◽  
Large Eddy ◽  
Hydrogen Flame

scholarly journals Inference of Reaction Kinetics for Supercritical Water Heavy Oil Upgrading with a Two-phase Stirred Reactor Model

2021 ◽  
Author(s):  
Ashwin Raghavan ◽  
Ping He ◽  
Ahmed Ghoniem
Keyword(s):  
Reaction Kinetics ◽  
Supercritical Water ◽  
Heavy Oil ◽  
Batch Reactor ◽  
Operating Conditions ◽  
Water Phase ◽  
Reactor Model ◽  
Two Phase ◽  
Stirred Reactor ◽  
Heavy Oil Upgrading

We present the development and application of a two-phase stirred reactor model for heavy oil upgrading in the presence of supercritical water (SCW), with coupled phase-specific thermolysis reaction kinetics and multicomponent hydrocarbon water phase equilibrium. We demonstrate the inference of oil and water phase kinetics parameters for a compact lumped reaction kinetics model through the application of this model to two different sets of batch reactor experiments reported in the literature. We infer that, though SCW can suppress the formation of newer polynuclear aromatics (PNA) from distillate range species, it is broadly ineffective in deterring the combination of pre-existing PNA fragments in the oil feed. Quantification of the conversion to distillate liquids before the onset of coke formation helps arrive at a clearer conclusion on whether the use of SCW in the batch reactor leads to better product outcomes for different oil feeds and operating conditions.

scholarly journals Characterization of NOx, N2O, and CO for Lean-Premixed Combustion in a High-Pressure Jet-Stirred Reactor

1996 ◽  
Author(s):  
Robert C. Steele ◽  
Jon H. Tonouchi ◽  
David G. Nicol ◽  
David C. Horning ◽  
Philip C. Malte ◽  
...  
Keyword(s):  
High Pressure ◽  
Computational Models ◽  
Chemical Reactor ◽  
Reactor Model ◽  
N2o Formation ◽  
Nox Formation ◽  
Lean Premixed Combustion ◽  
Stirred Reactor ◽  
Lean Premixed ◽  
In Series

A high-pressure jet-stirred reactor (HP-JSR) has been built and applied to the study of NOx and N2O formation and CO oxidation in lean-premixed (LPM) combustion. The measurements obtained with the HP-JSR provide information on how NOx forms in lean-premixed, high-intensity combustion, and provide comparison to NOx data published recently for practical LPM combustors. The HP-JSR results indicate that the NOx yield is significantly influenced by the rate of relaxation of super-equilibrium concentrations of the O-atom. Also indicated by the HP-JSR results are characteristic NOx formation rates. Two computational models are used to simulate the HP-JSR, and to provide comparison to the measurements. The first is a chemical reactor model (CRM) consisting of two perfectly-stirred reactors (PSRs) placed in series. The second is a stirred reactor model with finite rate macromixing (i.e., recirculation) and micromixing. The micromixing is treated by either coalescence-dispersion (CD) or interaction-by-exchange-with-the-mean (IEM) theory. Additionally, a model based on one-dimensional gas dynamics with chemical reaction is used to assess chemical conversions within the gas sample probe.

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