Analysis of heat-release during TNT/Aluminum afterburning by means of numerical simulations

2017 ◽  
Vol 36 (2) ◽  
pp. 2841-2848 ◽  
Author(s):  
E. Fedina ◽  
C. Fureby
Keyword(s):  
Numerical Simulations ◽  
Heat Release

Numerical Study of Vortex/Flame Interaction in Actively Forced Confined Non-Premixed Jets

1999 ◽  
Vol 122 (2) ◽  
pp. 376-380 ◽  
Author(s):  
K. R. Anderson ◽  
S. Mahalingam
Keyword(s):  
Numerical Simulations ◽  
Heat Release ◽  
Numerical Study ◽  
Fixed Level ◽  
Vorticity Production ◽  
Near Wall

Numerical simulations of coplanar reacting jets subjected to near wall confinement have been performed. The primary conclusion is that for a fixed level of heat release, the mechanism of baroclinic vorticity production increases with more severe wall confinement. [S0022-1481(00)00602-2]

scholarly journals Numerical Simulations of Urban Heat Release into Osaka Bay Considering Meteorological Data

2010 ◽  
Vol 66 (1) ◽  
pp. 1296-1300
Author(s):  
Nobuhito MORI ◽  
Yasuaki SACHI ◽  
Takaaki SHIGEMATSU ◽  
Masaki NAKAO ◽  
Susumu YAMOCHI ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Heat Release ◽  
Meteorological Data ◽  
Osaka Bay ◽  
Urban Heat

Development of Diesel Engine Emissions Control Models Based on Heat Release Rate Analysis of Combustion Processes

2011 ◽  
Author(s):  
Dong Wang ◽  
Chao Zhang
Keyword(s):  
Diesel Engine ◽  
Numerical Simulations ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Control Model ◽  
Premixed Combustion ◽  
Linear Control ◽  
Control Models ◽  
Nox Control

Linear control models to control the Nitrogen Oxides (NOx) and soot emissions from a diesel engine were developed through numerical simulations. A modified KIVA-3V code was used to calculate the NOx and soot formations in a direct injection diesel engine under different operating conditions. The following relationships between the pollutant formations and the heat release rate were observed: 1) NOx formation amount is related to the peak value of the heat release rate and the timing of the premixed combustion; 2) soot formation amount is related to the peak heat release rate and the soot oxidation amount is related to the timing of the premixed combustion. Based on the above observations, linear control models for NOx and soot emissions were constructed. The NOx control model developed through the numerical simulations was implemented into the controller of an EGR valve on a small diesel engine. The experimental results showed that the NOx control model was effective in reducing NOx emissions under high RPM conditions.

scholarly journals Direct Numerical Simulations of the Impact of High Turbulence Intensities and Volume Viscosity on Premixed Methane Flames

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Gordon Fru ◽  
Gábor Janiga ◽  
Dominique Thévenin
Keyword(s):  
Numerical Simulations ◽  
Heat Release ◽  
Turbulent Flame ◽  
Flame Structure ◽  
Turbulent Flames ◽  
Direct Numerical Simulations ◽  
Turbulent Reynolds Number ◽  
Volume Viscosity ◽  
Flame Structures ◽  
The Impact

Parametric direct numerical simulations (DNS) of turbulent premixed flames burning methane in the thin reaction zone regime have been performed relying on complex physicochemical models and taking into account volume viscosity (κ). The combined effect of increasing turbulence intensities (u′) andκon the resulting flame structure is investigated. The turbulent flame structure is marred with numerous perforations and edge flame structures appearing within the burnt gas mixture at various locations, shapes and sizes. Stepping upu′from 3 to 12 m/s leads to an increase in the scaled integrated heat release rate from 2 to 16. This illustrates the interest of combustion in a highly turbulent medium in order to obtain high volumetric heat release rates in compact burners. Flame thickening is observed to be predominant at high turbulent Reynolds number. Via ensemble averaging, it is shown that both laminar and turbulent flame structures are not modified byκ. These findings are in opposition to previous observations for flames burning hydrogen, where significant modifications induced byκwere found for both the local and global properties of turbulent flames. Therefore, to save computational resources, we suggest that the volume viscosity transport term be ignored for turbulent combustion DNS at low Mach numbers when burning hydrocarbon fuels.

The Aerodynamic Response of Fuel Injector Passages to Incident Acoustic Waves

2015 ◽  
Author(s):  
Jialin Su ◽  
Andrew Garmory ◽  
Jon Carrotte
Keyword(s):  
Numerical Simulations ◽  
Heat Release ◽  
Acoustic Waves ◽  
Gas Turbines ◽  
Experimental Measurements ◽  
Similar Data ◽  
Fuel Injector ◽  
Acoustic Characteristics ◽  
Fuel Injectors ◽  
Low Emission

Modern low emission combustion systems are more prone to combustion instabilities due to operation at lean conditions. The response of the airflow passing through the injector to incident acoustic waves is therefore of interest. Airflow fluctuations can initiate, for example, perturbations in stoichiometry and velocity that are subsequently delivered into the heat release region. In the case of liquid fuelled gas turbines the atomisation process will also be affected. Such effects can lead to further unsteady heat release and the generation of acoustic waves, thereby leading to combustion instability. This paper describes experimental measurements and the development of a numerical methodology by which the unsteady airflow response of complex, modern, low emission fuel injectors can be characterised. Single and two passage injector configurations have been investigated which broadly capture many of the features associated with modern fuel injectors. Although targeted at low emission (lean burn) liquid fuelled injector geometries, the methodology developed is thought applicable to a wide range of injector configurations. Initially experimental measurements were used to characterise the overall acoustic impedance of each injector design over a range of frequencies. Such information is also required for the low order thermo-acoustic network models, as typically used in the design process, to predict the stability of the combustion system. In addition to the experimental measurements a methodology was developed using unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations in which acoustic boundary conditions were implemented to reproduce the experimental scenarios. Interrogation of the pressure field enabled similar data analysis techniques to be applied to the numerical data for determining the injector acoustic characteristics. Fidelity of the numerical simulations is confirmed by the excellent agreement between the experimental data and numerical simulations. Furthermore, the unsteady flow field within the passages is difficult to access experimentally, but can be examined in more detail from the simulation results. In this way an improved understanding of the passage flows and their individual responses to the incident acoustic pressure waves can be obtained. The numerical approach is aimed at providing a computationally efficient and economic tool for predicting the acoustic characteristics of the complex geometries typical of modern fuel injector designs. Using this tool injector designs with different acoustic response characteristics can be developed relatively quickly.

Direct numerical simulations of a reacting mixing layer with chemical heat release

AIAA Journal ◽  
1986 ◽  
Vol 24 (6) ◽  
pp. 962-970 ◽  
Author(s):  
P. A. McMurtry ◽  
W.-H. Jou ◽  
J. Riley ◽  
R. W. Metcalfe
Keyword(s):  
Numerical Simulations ◽  
Heat Release ◽  
Mixing Layer ◽  
Direct Numerical Simulations ◽  
Chemical Heat

scholarly journals Research on the maximum fire smoke temperature beneath tunnel ceilings using longitudinal ventilation

2018 ◽  
Vol 251 ◽  
pp. 02020
Author(s):  
Hui Yang ◽  
Bingyan Dong ◽  
Sijian Zhang ◽  
Dahui Sun ◽  
Kirill Lushin
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Experimental Results ◽  
Small Scale ◽  
Longitudinal Ventilation ◽  
Fire Smoke

The maximum fire smoke temperature beneath tunnel ceilings using longitudinal ventilation was studied by both small-scale experiments and numerical simulations for a small heat release rate (HRR) fire. And then, the accuracy of the numerical simulation is verified. A numerical simulation is subsequently employed to modify the Kurioka model for cases in large HRR. Then, the modified Kurioka model is verified by various on-site high HRR fire experimental results conducted by other authors.

scholarly journals The role of surface fluxes in the development of a tropical-like cyclone in southern Italy

2008 ◽  
Vol 2 (1) ◽  
pp. 35-39 ◽  
Author(s):  
M. M. Miglietta ◽  
S. Davolio ◽  
A. Moscatello ◽  
F. Pacifico ◽  
R. Rotunno
Keyword(s):  
Tropical Cyclone ◽  
Numerical Simulations ◽  
Heat Release ◽  
Latent Heat ◽  
Initial Phase ◽  
Southern Italy ◽  
Surface Fluxes ◽  
Mature Stage ◽  
Latent Heat Release

Abstract. Numerical simulations of a tropical-like cyclone in southern Italy have been performed with two different modelling systems (BOLAM-MOLOCH and WRF) with the aim of discussing the role of the surface fluxes in the development of the vortex and evaluating their intensity during the mature stage of the cyclone. Although significant differences emerge in their intensity, both the modelling systems agree in showing that the surface fluxes are more important than the latent heat release associated with convection in the initial phase of the vortex lifecycle, while they are less relevant (although more intense) when the minimum assumes the characteristic of a tropical cyclone.

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