Document Type : Research Article

Authors

1 Assistant Professor. Aerospace Research Institute, Ministry of Science, Research and Technology, Tehran, Iran.

2 Ph.D. Aerospace Research Institute, Ministry of Science, Research and Technology. Tehran. Iran.

Abstract

Due to environmental requirements in reducing aircraft noise, using acoustic liners at the inlet of turbofan engines is necessary. These liners are designed in different geometries. Understanding the effects of different parameters in the design of these liners is essential. In this paper, one of the common examples, folded cavity liners (L-shaped), is investigated. The advantage of this geometry is reducing the space required to use the liner while maintaining the liner's depth. In the present paper, Comsol Multiphysics to simulate the acoustic of folded cavity liners numerically, and the effect of honeycomb cell height is investigated. The simulation results show that increasing the height of honeycomb cells at low frequencies (f <1700 Hz) increases the sound absorption coefficient, while at frequencies above 1700 Hz, the sound absorption coefficient decreases, and this decrease is very high at frequencies above 3500 Hz. Based on the simulation results for the general geometry considered in the present study, a height of 20 mm is an appropriate value for the height of honeycomb cells. In the present study, the numerical results are compared with experimental and analytical results, indicating the simulation results' good accuracy. This confirms the use of 2D numerical simulation in the initial design phase of acoustic liners and the parametric study of a similar problem.

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Main Subjects

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