Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Aerospace Engineering


Aerospace Engineering

First Advisor

Paul Durbin


Combustion systems in gas turbine engines are subjected to particular scrutiny in regards to the emissions which they produce. Of special interest are the emissions of Oxides of Nitrogen (NOx), which have a direct impact on air quality as well as health aspects. There is a need in the industry for elegant designs for these combustion systems which reduce the formation of NOx. The present study includes an in depth analysis of a state-of-the art prefilming airblast injector which is designed for achieving low NOx. The design has been studied through the use of turbulence resolving simulation to differentiate what is important for the design of this system. The OpenFOAM CFD software, with a Delayed Detached Eddy Simulation (DDES) model recently developed at Iowa State University, is shown to provide a suitable design tool which has been used to accurately predict a variety of parameters important to this combustion system. Of particular interest are the mixing characteristics of the atomizer, which have been studied through a series of CFD simulations including single-phase, multi-species, and multi-phase simulations.

Turbulence simulations are validated by comparison to United Technologies Aerospace Systems (UTAS) data with air only. It is shown how DDES is able to capture the downstream mixing of air streams.

Finally, a novel atomizer has been designed with these methods which is intended to promote thorough mixing. The CFD mixing characteristics are described and compared to the existing injector.


Copyright Owner

Jason Allen Ryon



File Format


File Size

161 pages