Doctoral Defense: Chiluwata Lungu

Mon Jul 02 2018 01:00 PM to 03:00 PM
MK 317
An Experimental Study of Mixing in Compressible Shear Layers

You're invited to hear a

Ph.D. Defense

by

Chiluwata Lungu

(Advisor: Prof. Jagoda)

 “An Experimental Study of Mixing in
Compressible Shear Layers”

1 p.m., Monday, July 2
MK 317

 

Abstract:
Supersonic combustion ramjets (scramjets) are the preferred propulsion systems for atmospheric hypersonic flight because of their simplicity and relatively high efficiency. However, the high speed of the airstream in the scramjet combustor results in short residence times for a combustor of reasonable length. This makes fuel-air mixing and flame-holding challenging. Therefore, an experimental study of fuel‑air mixing in compressible mixing layers behind a backward-facing step was conducted using Schlieren and fine-scale resolution acetone planar laser-induced fluorescence (PLIF) techniques. The primary goal of this work was to characterize the spatial dependence of molecular mixing in supersonic shear flows and to shed more light on the underlying physical mechanisms responsible for mixing in these types of flows. In contrast to previous studies, this research quantified the degree and spatial dependence of molecular mixing in supersonic shear flows behind a backward-facing step, at scales much closer to the Batchelor scale, over a range of transonic convective Mach numbers. This configuration was investigated because it is a more practical and appropriate geometry for a scramjet fuel injector than a splitter plate used in most previous studies. This type of flow field provides better flame-holding and flame stabilization.

Committee:

  • Prof. Jechiel Jagoda, Georgia Institute of Technology, School of Aerospace Engineering (advisor)
  • Prof. Suresh Menon, Georgia Institute of Technology,  School of Aerospace Engineering
  • Prof. Jerry Seitzman, Georgia Institute of Technology, School of Aerospace Engineering
  • Prof. David Scarborough, Auburn University, School of Aerospace Engineering
  • Prof. Ari Glezer, Georgia Institute of Technology, School of Mechanical Engineering

Location

MK 317