Ключевые слова: газодинамика горения, устойчивость горения, концентрацион-ные пределы горения, прямое численное моделирование. GAS-DYNAMIC PROCESSES INFLUENCE ON COMBUSTION EVOLUTION CLOSE TO CONCENTRATION FLAMMABILITY LIMITS M.F. Ivanov, A.D. Kiverin, I.S. YakovenkoJoint Institute for High Temperatures, Russian Academy of Sciences, Moscow, Russian Federation e-mail: ivanov_mf@mail.ru; alexeykiverin@gmail.com; yakovenko.ivan@bk.ruThe paper considers numerically the influence of gas-dynamic processes on combustion propagation within the enclosed volumes filled with low active gaseous fuel-air mixtures close to the concentration flammability limit. The authors identify some physical mechanisms determining both the flame propagation instability and the formation of modes with a cellular nature of flammable mixture combustion. Of special interest is a buoyancy of hot combustion products in the gravity field, as well as the convective instability being developed during this process. On the one hand, the convective instability provides both the stratification of unburnt mixtures and

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