Degree Type

Dissertation

Date of Award

2018

Degree Name

Doctor of Philosophy

Department

Aerospace Engineering

Major

Aerospace Engineering

First Advisor

Hui Hu

Abstract

Aero-engine icing is widely recognized as a significant hazard to aviation safety in cold weather. During flights, upon the impingement of small, super-cooled, airborne water droplets in clouds, ice accretion would occur on the exposed surfaces of aero-engines, such as inlet lips, spinners, fan rotor blades, and inlet guide vanes. Ice formation on such components can significantly degrade the performance of aero-engines. The ice accretion over the fan blades and spinner surface can also result in an imbalance rotation of the rotor to cause serious mechanical vibrations. Furthermore, the ice shedding from these surfaces may cause damages to the fan rotor and components behind the fan, even be sucked into the core engine resulting in a severe stall, surge, or flameout.

By using the Icing Research Tunnel of Iowa State University (i.e., ISU-IRT), a series of experimental studies were conducted to investigate the dynamic ice accretion process on the surface of an aero-engine spinner-fan model and to explore the feasibility of different anti-/de-icing technologies. At first, the dynamic ice accretion process on three different kinds of aero-engine spinners (i.e., conical, coniptical and elliptical) was examined. The trajectories and impingement characteristics of super-cooled water droplets were characterized by using a digital Particle Image Velocimetry (PIV) system. An infrared (IR) thermal imaging system was also used to quantify the unsteady heat transfer process over the surface of the aero-engine spinner models under different icing conditions. The transient ice accretion process over the rotating fan blades of an aero-engine fan model and the effects of ice accretion on the aerodynamic performance of the fan unit model were investigated. An explorative study was also conducted to use a bio-inspired super-hydrophobic coating for aero-engine icing mitigation. Finally, the anti-/de-icing performance of a hot-air circulating system for an engine inlet guide vane (IGV) was also evaluated under different icing conditions.

The findings derived from the present study will provide a better understanding about aero-engine icing phenomena, which will lead to more effective and robust anti-/de-icing strategies to ensure safer and more efficient operation of an aero-engine in cold weather.

Copyright Owner

Linkai Li

Language

en

File Format

application/pdf

File Size

156 pages

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