Experimental observation of pulsating instability under acoustic field in downward-propagating flames at large Lewis number
نویسندگان
چکیده
منابع مشابه
Lewis Number Effects in Distributed Flames
Recent computational studies have simulated a mode of distributed premixed combustion where turbulent mixing plays a significant role in the transport of mass and heat near the reaction zone. Under these conditions, molecular transport processes play a correspondingly smaller role. A consequence of burning in this regime is that a change in the gas mixture composition can occur within the flame...
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A recent numerical study of turbulence-flame interactions in lean premixed hydrogen, where the Lewis number was approximately 0.36, observed that flames at different equivalence ratios presented significantly different behavior despite having the same Karlovitz and Damköhler numbers. This differing behavior is due to the thermodiffusively-unstable nature of low Lewis number flames. In more than...
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The dynamic behavior of freely propagating premixed flames with large Lewis numbers was computationally simulated using a sixth-order central difference scheme and non-reflective boundary conditions. Results in the linear stage of the instability growth show that the growth rate dramatically decreases with increasing Lewis number and that the large activation energy excites the pulsating instab...
متن کاملEffects of Lewis Number on Temperatures of Spherical Diffusion Flames
Spherical diffusion flames supported on a porous sphere were studied numerically and experimentally. Experiments were performed in 2.2 s and 5.2 s microgravity facilities. Numerical results were obtained from a Chemkin-based program. The program simulates flow from a porous sphere into a quiescent environment, yields both steady-state and transient results, and accounts for optically thick gas-...
متن کاملQuantitative Phase-Field Modelling of Solidification at High Lewis Number
A phase-field model of non-isothermal solidification in dilute binary alloys is used to study the variation of growth velocity, dendrite tip radius and radius selection parameter as a function of Lewis number at fixed undercooling. By the application of advanced numerical techniques we have been able, for the first time, to extend the analysis to Lewis numbers of order 10000, which are realisti...
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ژورنال
عنوان ژورنال: Combustion and Flame
سال: 2018
ISSN: 0010-2180
DOI: 10.1016/j.combustflame.2017.09.026