Seminar - Numerical Simulation of Broadband Noise for Aeroengines by Prof Xin Zhang
日期：2016 年 04 月 18 日 ( 星期一)
Time：11:00 am – 12:00 pm
Aero-engines are a major source of noise in the current generation of commercial aircraft. Tonal noise generated at the blade passing frequency and its harmonics is well understood. Today, the challenge is to also reduce broadband noise through computationally efficient simulations of turbofan and contra-rotating open rotor engine noise. In turbofan engines, the dominant source of broadband noise is related to interactions between fan wakes and the outlet guide vanes (OGVs). Fan wake statistics can be reproduced by a synthetic turbulence method and interactions between the wakes and the OGVs are modelled by computational aeroacoustics (CAA) simulations that solve the linearised Euler equations. Contra-rotating open rotor engines (CRORs) are being considered for next generation aircraft because they can offer improvements in propulsive efficiency when compared with turbofans. Unfortunately, CRORs emit strong tonal and broadband noise, which must be mitigated before their entry into service. Improvements have been made in tonal noise emissions via the use of technologies such as cropped rotors and mismatched blade numbers. However, broadband noise, particularly at high speeds, requires further study for a more complete understanding. The talk will describe CAA methods for high-speed CROR broadband noise simulations to better understand the noise mechanisms.
Xin Zhang is the Swire Professor of Aerospace Engineering at the Hong Kong University of Science and Technology. Xin Zhang holds a Ph.D degree in fluid mechanics from the Cambridge University, UK and B.Eng in aerospace engineering from Beijing University of Aeronautics and Astronautics, China. He is a fellow of the Royal Aeronautical Society. Dr. Zhang lectures in aerodynamics and aeroacoustics, in particular aircraft aerodynamics and noise. He has performed experimental and computational research in the area of unsteady aerodynamics, ground effect aerodynamics, aeroacoustics, and aircraft noise. He now works in the area of aircraft noise including both airframe and propulsive unit noise. His research over a period of 25 years led to the establishment of Airbus Aircraft Noise Technology Centre (ANTC) at Southampton in 2008. The centre is the only Airbus university based technology centre in the world. ANTC works in the areas of airframe noise, engine noise, physics-based aircraft noise models, computational aeroacoustics, aircraft interior noise modelling, sound transmission, and noise control, all with Airbus. Airbus, a company that produces around half of the world’s aircraft and employs more than 60,000 people across the EU, has integrated the outcomes of Zhang’s research into its key design processes. He was the Airbus Professor of Aircraft Engineering and served as the director of ANTC between 2008 and 2014. Xin Zhang is now the director of Aviation Industry Corporation of China Advanced Aircraft Noise Technology Centre at HKUST.