We explore the detailed structure of heat release and the energy budget for a freely-propagating lean, premixed hydrogen flame. At lean conditions, the flame is thermodiffusively unstable and spontaneously develops the cellular burning structures, characteristic of this type of flame. The instabilities in the system saturate quickly, resulting in robust, slowly evolving cellular burning feature...

We study the dynamics and properties of a turbulent flame, formed in the presence of subsonic, high-speed, homogeneous, isotropic Kolmogorov-type turbulence in an unconfined system. Direct numerical simulations are performed with Athena-RFX, a massively parallel, fully compressible, high-order, dimensionally unsplit, reactive-flow code. A simplified reaction-diffusion model represents a stoichi...

A flame shape descriptor based on coordinates of edge of a flame is proposed. Artificial Neural Network is used to predict flame image edges .A flame with constant x-coordinate is used in the present study. Y-coordinates of flame edge are predicted using neural network. Recognition experiments were carried out using flame image sampled from a burning candle. The results show a good recognition ...

To reveal the inner mechanism of gas explosion dynamic behavior affected by gas equivalent concentration, a high speed Schlieren image system and flow field measurement technology was applied to record the gas explosion flame propagation and flame structure transition. The results show that a flame front structure transition occurs, followed by a flame accelerating propagation process. The lami...

The Olympic flame and torch are significant symbols of the Olympic Games and are important in linking the general public with the festival. They are internationally recognized symbols, particularly important at the Opening and Closing Ceremonies. “It is through the opening and closing ceremonies and the torch relay that the Olympiad must distinguish itself from another series of world champions...

O mundo empresarial é repleto de situações complexas e inovadoras. Diante disso, muitos empresários buscam meios para se adequar às diversas normas impostas pela regulamentação civil comercial. Nesse contexto nasceu a necessidade criação uma empresa, que orientasse desse sequência aos objetivos da firma, como forma proteção dos bens conquistados no decorrer décadas. Para tanto, observando as ne...

A retrospective analysis was conducted on air samples that were collected in 2005 under the Global Atmospheric Passive Sampling (GAPS) Network around the time period when the Stockholm Convention on Persistent Organic Pollutants came into force. Results are presented for several new flame retardants, including hexabromocyclododecane (HBCD), which was recently listed under the Convention (2013)....

In previous studies, we examined turbulence-flame interactions in carbonburning thermonuclear flames in Type Ia supernovae. In this study, we consider turbulence-flame interactions in the trailing oxygen flames. The two aims of the paper are to examine the response of the inductive oxygen flame to intense levels of turbulence, and to explore the possibility of transition to detonation in the ox...

A computational study has been conducted to determine the critical conditions for the transition from localized flame ignition and propagation to the establishment of a flame ball. Lean H2/air mixtures are investigated using a time-dependent, spherically symmetric code with detailed chemistry, transport, and radiation submodels. Results show that outwardly propagating spherical flames can be ig...

In this paper we study the behavior of a premixed turbulent methane flame in three dimensions using numerical simulation. The simulations are performed using an adaptive time-dependent low Mach number combustion algorithm based on a second-order projection formulation that conserves both species mass and total enthalpy. The species and enthalpy equations are treated using an operator-split appr...