چكيده به لاتين
Abstract
One of the most important issues in relation to the combustion process is to identifying effective mechanisms of instabilities. For combustion instabilities, with devastating effects on the performance of combustion systems and combustion conditions may be effects on destroying of combustion systems. Among the factors of generating the combustion instabilities, entropy waves are more important. Entropy waves are Non-uniformities in combustion gas temperature, which have been created due to the unstable combustion and transmitted along with the flow. Acceleration of entropy wave in the nozzle of the combustion chamber results in the production of pressure oscillations which is called entropy noise. Entropy noise in addition, increases the gas turbine noise which may be returned into the combustion chamber and leading to instability in the ignition. One thing about the entropy wave is controversial in the literature, reaching or not reaching the entropy wave to the nozzle of downstream of the combustion chamber. Few studies of this area are incomplete and in some cases contradictory.
The aim of the research is investigation of entropy wave in a very simple state, which is to phenomenology. In fact, this study is looking for an empirical modeling of the entropy wave transmission to have an overview of how the dissipation and dispersion of entropy wave occur. The effect of various parameters, including Reynolds number of flow, turbulence intensity of flow and heat transfer conditions of the channel wall will be investigated.
Keywords: Combustion instability, entropy waves, dissipation and dispersion
