Edward Guzman

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Faculty Mentor: Ahmed F. Ghoniem

Direct Supervisor: Santosh Shanbhogue

Home University: California State Polytechnic University, Pomona

Major: Aerospace Engineering

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Biography

I am a senior at California State Polytechnic University, Pomona where I am majoring in Aerospace Engineering with a minor in Mathematics. My research interest include fluid dynamics, heat transfer, and thermodynamics to develop new technologies that will contribute to a better environment, as for example, developing new propulsion systems that will be more environmentally friendly while at the same time more efficient in cost and performance. Thus, upon completion of my undergraduate studies, I want to attend graduate school to pursue a Ph.D. in engineering to further expand my knowledge and eventually to contribute to a better environment, as well as to serve as role model for younger generations, especially Hispanics, so they get inspired and motivated to pursue careers in science and engineering. In my spare time, I like playing sports and being with my family.

Abstract

Vortex Breakdown Characteristics of Reacting Swirling Flows in Oxy-Fuel Combustion

In recent years, the demand for energy has increased due to population growth and increased per capita energy usage worldwide.  Currently, most of this energy is generated by air breathing turbine engines whose emissions are severely affecting the atmosphere.  Oxy-fuel combustion is a feasible alternative for zero combustion emissions.  In this mode of combustion, fuel is burnt in pure oxygen by separating N2 from air prior to combustion, resulting in a pure CO2 exhaust stream that can be easily sequestered.  However, the substitution of air with oxygen affects the stability of the combustion and the flame temperature.  Our goal was to determine the precise mechanism behind the flame vortex breakdown in oxy-fuel combustion.   For this we produced high speed images of the flame taken at different equivalence ratios and Reynolds numbers for Methane-Air mixtures.  This data demonstrated that three different vortex breakdowns exist: (1) an axis-symmetric bubble, (2) a double helix, and (3) a spiral vortex breakdown.  We analyzed our findings and discovered that each vortex breakdown severely affected the flame length, and possibly the stability of the combustor.  Our results indicate that slight change in equivalence ratio could potentially affect the flow field inside the combustor and produce combustion instabilities.  These results provide the platform for future research on the instabilities of oxy-fuel combustion by correlating the flow field and flame geometries with the underlying mechanism behind vortex breakdown.  Future research optimizing the combustion process will further the fight to lower emissions products, and thus contribute to a better and cleaner environment.