Inertial-range cascade phenomenology is used to predict Prandtl-number (Pr) dependencies of turbulent flame properties. A unified picture of turbulent flame structure and burning velocity is developed that encompasses all Pr regimes. Implications of the analysis for gaseous flames (Pr near unity), autocatalytic fronts in liquids (high Pr), and astrophysical flames (low Pr) are noted.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1103/PhysRevE.64.066306 | DOI Listing |
ACS Omega
January 2025
College of Resource and Environment Engineering, Jilin Institute of Chemical Technology, Jilin, Jilin 132022, China.
The inhibition of methane-air explosions by air jet-driven NaHCO powders and porous barriers was investigated in this study. Flame images and overpressure data were recorded using high-speed cameras and pressure sensors. The inhibition mechanism of NaHCO powder was further investigated using the reaction mechanism of sodium-containing substances and methane combustion.
View Article and Find Full Text PDFBoundary Layer Meteorol
April 2024
Department of Civil and Environmental Engineering, University of California, Irvine, CA 92697 USA.
Wildland fire-atmosphere interaction generates complex turbulence patterns, organized across multiple scales, which inform fire-spread behaviour, firebrand transport, and smoke dispersion. Here, we utilize wavelet-based techniques to explore the characteristic temporal scales associated with coherent patterns in the measured temperature and the turbulent fluxes during a prescribed wind-driven (heading) surface fire beneath a forest canopy. We use temperature and velocity measurements from tower-mounted sonic anemometers at multiple heights.
View Article and Find Full Text PDFEnergy Fuels
October 2024
College of Physical Sciences and Engineering, Cardiff University, Cardiff, Wales CF24 3AA, U.K.
Climate change and global warming necessitate the shift toward low-emission, carbon-free fuels. Although hydrogen boasts zero carbon content and high performance, its utilization is impeded by the complexities and costs involved in liquefaction, preservation, and transportation. Ammonia has emerged as a viable alternative that offers potential as a renewable energy storage medium and supports the global economy's decarbonization.
View Article and Find Full Text PDFExp Fluids
October 2024
Laboratory of Measurement and Sensor System Technique, Faculty of Electrical and Computer Engineering, Technische Universität Dresden, Helmholtzstrasse 18, 01062 Dresden, Germany.
In aircraft engines, thermoacoustic oscillations in the combustion chamber contribute significantly to noise emissions, which, like all other emissions, must be drastically reduced. Thermoacoustic oscillations are not only a concern, they can also be beneficial in hydrogen combustion. This work demonstrates that thermoacoustic density oscillations with amplitudes at least an order of magnitude smaller than those resulting from density gradients in a turbulent flame can be detected using laser interferometric vibrometry.
View Article and Find Full Text PDFACS Omega
September 2024
Marine Engineering College, Dalian Maritime University, Dalian 116000, China.
Explosion venting is an effective method to reduce the explosion damage; in order to study the mechanism of an explosion venting process in internal and external space, this paper investigates the influence of vent parameters on hydrogen-air explosion in a rectangular duct through numerical simulation. The model including the internal and external space is first constructed, and then the explosion dynamic behaviors of the full flow field are analyzed under different vent pressures and sizes. The study aims to reveal the coupling effect of the flame, pressure, and flow field on hydrogen explosion venting.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!