题目：Importance of Fundamental Science in Aircraft Engine

报告人：Wei Chen, Ph.D

时间：2019年4月12日上午10：30

地点：betway必威雅各楼116室

欢迎各位师生踊跃参加！

Abstract text:

 Aircraft engine is probably one of the most advanced manufacturing products in our society.  It embodies many aspects of science and engineering and it is no doubt that the fundamental science and technology is crucial for the development of aircraft engines.  Because of that, the manufacturing of aircraft engines will greatly drive not the engineering and manufacturing but also fundamental sciences.

Here I want to briefly touch some areas that have been of great interests from aviation industry.  Those areas are fluid dynamics, turbulence, multiphase flow, heat transfer and reaction and thermodynamics.

On 27 November 2008, as the A320 came off from XL airway to air New Zealand, the airplane caught up by an exceeding angle of attack during taking off.  The issue later discovered that the two probes were congested with water and frozen at higher altitude.  Airplane lost their accurate information on the angle of attack.  Icing is a very fundamental science subject.  The thermodynamics of crystal icing and natural icing place a challenge for engineers to design aircraft engine, as well deicing.  The structure of ice and how water converts into icing is a multiphase flow and thermodynamics problem.

In a combustion system, liquid fuel is injected into combustion and the spray breaks into small droplets and ligaments, eventually vaporized into gaseous phases.  Sometimes, liquid droplets volatilized quickly and solidified into carbon particles.  The carbon particles can deposit on the wall or emitted into gaseous stream.  The fundamental understanding of liquid breakups and deposition are very much lacking.

Heat transfer and fluid dynamics in turbomachinery directly affects the life of components.  In turbomachinery, gaseous heat transfer on the solid surfaces is dominated by convective or more precise advective heat transfer and the convective heat transfer is determined by the flow field.  In particular the boundary layer along solid surface provides the most the thermal resistance and therefore, the questions are raised on the validity of conventional boundary theory.

One of major issues in turbomachinery is the aeroacoustics or thermal acoustics.  Both of them are associated to the turbulence flow.  Recent development of computational fluid dynamics (CFD) such as LES (Large eddy simulations), DNS (Direct Numerical Simulations) has been used to investigate the long standing the fundamentals of turbulence.  Especially, the fundamentals of fluctuations of turbulence flow may help improve our understanding of the flows and behaviors in turbomachinery. 

Biography:

Dr. Chen is responsible for the development and application of computational fluid dynamics, fundamental physics and combustion models in physics and validation of combustion models, combustor design simulations, predictions of emissions, aero and thermo acoustic predictions, thermal loads and heat transfer coefficients for combustor durability. He is Senior Consulting Engineer of ANSYS Inc.