Bora Kalpakli

In this project, I was responsible for analyzing interface instabilities between plasma gas and external structures. I used my own in-house Hydrocode solver to investigate the effects of these multi-dimensional interface instabilities on fusion conditions.

In this work, I was responsible for developing a CFD code for full simulation of big solid rocket motors including particle effects. This code is based on the previous studies I had completed, and some extra models are added such as particle coalescence and breakup based on Interfacial Area Transport approach, which is a strong alternative to population balance models. This solver can solve both steady and time-accurate transient problems such as ignition transients. We are also using this solver for acoustic and hydrodynamic instability problems with particle effects. I also developed C++ types from scratch for fast automatic calculation of Jacobians based on operator overloading with some new methods available such as expression templates.

I developed a detailed computational model for boron particle combustion in varying composition environments. The main application area of the model is Computational Fluid Dynamics (CFD) based simulations of solid propellant ramjet combustion chambers and it is aimed to construct a combustion model for boron-containing solid propellants. This model includes physical processes required to define a high fidelity particle combustion simulation. The combustion model consists of surface and gas-phase reactions for ignition and combustion of particles along with phase change processes including melting, evaporation, and boiling. The reaction rate modeling in similar studies are improved and corrected for ramjet combustion chambers and this model provides better predictions for all particle sizes. The reactions in ignition stage are reformulated as competing reactions for consumption of (BO)n polymers. Large discrepancies between experimental and calculated ignition times for small particles in previous models are eliminated. The developed model is added to a multi-dimensional CFD solver and is used along with gas-phase detailed turbulent combustion simulations of ducted rocket combustion chambers. This simulation approach provided a powerful and reliable design tool for side dump combustion chambers of ducted rockets with boron particle fuels. This detailed combustion model is validated with existing experimental results available in the open literature. The model is also compared with the results of similar studies.