In this installment of a 13-part series of articles, The Combustion Institute recognizes the 2019 Distinguished Papers selected from among the scientific papers presented during the 37th International Symposium on Combustion. Congratulations to Alanna Y. Cooney and Simcha L. Singer for winning the DPA in the Spray, Droplet, and Supercritical Combustion colloquium.

Their authoritative paper, A hybrid droplet vaporization-chemical surrogate approach for emulating vaporization, physical properties, and chemical combustion behavior of multicomponent fuels, has substantially improved research in spray combustion and the predictive modeling of multicomponent droplet vaporization. This research employed a hybrid approach, combining droplet vaporization models with surrogate fuel models to address the issue of preferential vaporization.

Typically, surrogates used in CFD simulations of spray combustion contain a limited number of hydrocarbon species that emulate the behavior of the real fuel. These surrogates are formulated to match the combustion properties of the full fuel if it existed in the gas-phase in the same proportions as in the original liquid. However, because species vaporize at different rates (preferential vaporization) the gas-phase composition is not identical to that of the full liquid fuel and may vary spatially. Therefore, CFD simulations using these surrogates may not accurately predict the combustion properties of the gas-phase.

Their hybrid approach employs a computationally efficient “continuous thermodynamic” droplet vaporization model that can be used to generate a time-varying surrogate flux that matches the combustion properties in the flux from a vaporizing droplet comprised of the full fuel. The impact of their hybrid approach is increased accuracy and predictive capabilities for CFD codes for spray combustion and a better representation of the effects of preferential vaporization. The goal of improving the accuracy of CFD codes is ultimately to lead to more efficient, stable and powerful engines.

The team began their efforts to combine continuous thermodynamic methods for droplet vaporization with surrogate generation in late summer of 2017. They performed their research and supporting work at Marquette University. The team continues to improve upon the flexibility and efficiency of their hybrid approach.

Over 1,600 papers were submitted to the 37th Symposium in 13 combustion science colloquia. Those papers were categorized by teams of colloquium coordinators and co-chairs, and then distributed to approximately 1,000 scientific reviewers. One paper in each discipline was awarded the recognition of Distinguished Paper.

The 13 Distinguished Papers undergo committee review for consideration to receive the Silver Combustion Medal that will be awarded during the 38th International Symposium in Adelaide, Australia. A paper selected for this honor exemplifies quality, achievement, and significance to advance a field of combustion science. Distinguished papers are selected biennially from among the scientific papers presented during the International Symposium on Combustion and accepted for publication in the Proceedings of The Combustion Institute.