“To flame or not to flame... that is the burning question”
Work towards PhD degree under the supervision of Professor Emeritus Yeshayahou Levy (Technion)
Department of Aerospace Engineering
Technion – Israel Institute of Technology
Since the advent of gas turbines (GTs), the only method to achieve complete combustion in GT combustors has involved establishing favorable conditions for the propagation of a stable flame in the primary zone. When a flame is stabilized within the combustor volume, the combustion heat release processes occur in a relatively small volume leading to highly localized, high temperature regions. Pollutant formation, especially nitrogen oxides (NOx), is a major problem at these high temperature levels, but lowering the adiabatic flame temperature through fuel lean combustion can lead to the unstable growth of highly detrimental combustion instabilities. Hence, a combustor design is needed which can achieve complete combustion under low equivalence ratios (and low adiabatic flame temperatures) without flame propagation and is unconditionally stable to combustion instabilities.
The current research aims to achieve such a flameless combustor by developing a clear, precise definition of this technological process. A theoretical criterion to achieve flameless combustion is derived and its ability and limitations to help in the design of this new class of combustors are discussed. The study uses unsteady and steady perfectly stirred reactor models and residence time distribution studies to provide a theoretical framework for designing flameless combustors. A phenomenological model to enable the proper implementation of flameless combustion in practice, and the limitations imposed by mixing processes are discussed. The main conclusions are that internal recirculation of exhaust gases promotes spontaneous reactions while inhibiting flame propagation, and free radicals in the recirculated flow promote transition to an ignition-dominated combustion regime.
The talk will be given in English
Wed, 27-07-2022, 13:30-14:30 (Gathering at 13:30)Classroom 165, ground floor, Library, Aerospace Eng. & https://technion.zoom.us/j/98121356503?pwd=Wjd5K2hkSUcva0d0RVhNemVZblV1dz09
Light refreshments will be served before the lecture at the classroom