Time-domain characterization of the acoustic damping of a perforated liner with bias flow

• Main Authors: Zhong, Zhiyuan, Zhao, Dan
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Article
• Language: English
• Published: 2014
• Subjects: Mechanical and Aerospace Engineering
• Online Access: https://hdl.handle.net/10356/101573; http://hdl.handle.net/10220/18696
• Institution: Nanyang Technological University

Combustioninstabilities are caused by the interaction of unsteady heat releases and acoustic waves. To mitigate combustioninstabilities, perforated liners, typically subjected to a low Mach number bias flow (a cooling flow through perforated holes), are fitted along the bounding walls of a combustor. They dissipate the acoustic waves by generating vorticity at the rims of perforated apertures. To investigate the absorption of plane waves by a perforated liner with bias flow, a time-domain numerical model of a cylindrical lined duct is developed. The liners’ damping mechanism is characterized by using a time-domain “compliance.” The development of such time-domain compliance is based on simplified or unsimplified Rayleigh conductivity. Numerical simulations of two different configurations of lined duct systems are performed by combining a 1D acoustic wavemodel with the compliance model. Comparison is then made between the results from the present models, and those from the experiment and the frequency-domain model of previous investigation [Eldredge and Dowling, J. Fluid Mech. 485, 307–335(2003)]. Good agreement is observed. This confirms that the present model can be used to simulate the propagation and dissipation of acoustic plane waves in a lined duct in real-time.