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The prediction of the turbulent burning velocity plays a crucial role in the modeling of SI engine combustion. The laminar flame speed is one of the most important scaling factors in most of the published correlations for the turbulent flame speed.
Figure A.1.4-1 shows the measured turbulent combustion rates ST of a lean hydrogen-air mixture (f = 0.26) as a function of the turbulent intensity in the pressure range from 1 to 5 bar.
The proposed expression for the turbulent propagation speed highlights the quadratic dependence from turbulence intensity being modulated by two coefficients depending respectively on expansion ratio and on integral scale, and a is a proportionality constant.
Main goal of current work was an experimental evaluation of such fundamental properties of hydrogen-air mixtures as flammability limits and laminar flame speed at sub-atmospheric pressures. A spherical explosion chamber with a volume of 8.2 dm3 was used in the experiments.
Objective 1: Development of comprehensive database on autoignition delays for hydrogen containing fuels, including pure hydrogen and ammonia, hydrogen/natural gas blends, and ammonia/hydrogen blends at realistic gas turbine conditions.
uate to study extinction. Numerical calculations by Warnatz & Peters (1984) incorporating detailed kinetics show that a rich hydrogen-air flame (Le ~ 3) can be extinguished, and the calculations of Rogg(reported by Peters 1986) based on a four-step scheme show that a stoichiometric methane-air flame can also be
cale, the Kolmogorov length scale, and the turbulent intensity. The model identifies the laminar burning of the fuel-air mixture across the microscale as being the critical process for tur- bulent flame stabilization. The correlation is based on a Karlovitz analysis where two characteristics times - a chemical time a
Abstract−To explore the influence mechanism of initial turbulence on propagation speed of wrinkled flames, the tur-bulent combustion behavior of wrinkled stoichiometric hydrogen premixed flames was studied in a spherical fan-stirred closed vessel under standard temperature and pressure.
It is intuitive to attribute such increase on the turbulent flame speed to the enhancement of flame instabilities via the thinner flame at higher pressure (5 atm), since the fine scales that are all over the surface of turbulent spherical flames (column 2) are observed.
Hydrogen has particularly significant influences on the turbulent flame speed. This paper presents new H 2 / CH 4 data of high pressure, high hydrogen turbulent burning velocities. The datasets were designed to address fundamental questions as well as provide engineering/design relevant insights.