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The airflow in the can combustion generates significant instabilities. This interaction between the airflow and the combustor walls will induce vibration, which might result as strong fluctuations in the wall structure of the combustor. The present work is investigating the flow induced vibration, and four different locations have been selected to measure the velocity distribution, turbulent intensity, and static pressure recovery coefficient under forced vibration at three different frequencies (34, 48, 65 and 80 Hz) in the upper annulus of the Can Combustor. This phenomenon has been studied experimentally and numerically. The Computational Fluid Dynamics analysis was accomplished by utilizing the Shear-Stress Transport (SST) k-omega model to predict the flow velocity at the recirculation zone. The vibration testing equipment was designed and used to apply the excitation forces on the wall combustor. It has been explained that the reversed flow which causes eddies inside the recirculation region can be increased at higher frequencies. In addition to that, exciting the system with higher frequencies would increase the turbulence intensity causing a recirculation region enlargement. The Computational results were compared against the experimental results, and they show a very good agreement. On the other hand, the static pressure distribution has been decreased while increasing the frequency. It has been proved that the frequency values play an essential role to predict the system behavior.
annulus flow, can combustor, CFD Simulation, pitot - static tube, velocity profile, fluid-structure interface, forced vibration and flow-induced vibration
This work was supported by the University of Babylon/ Mechanical Engineering department for the use of their facilities. The authors would also like to show their gratitude to the Gas Generating Station Staff for their assistance in carrying out this work.
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