Experimental study of bluff-body stabilized highly turbulent premixed flames using pre-vaporized liquid fuels

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This project is an experimental investigation of highly turbulent premixed flames for propulsion applications. High level of flow turbulence is a common feature of many propulsion systems to generate high power in a small space. Scientific knowledge of flame interactions with high turbulence is still lacking. This study will contribute to better understanding of flame-turbulence interactions using key jet fuels. The team will conduct this research to provide high quality experimental data for public use. Technical potential benefits of this research will be better design of combustion systems for stable operation and pollutant reduction. High-efficiency and low-pollution combustion systems will benefit both environment and health. This project also contributes to the development of highly-skilled workforce by training advanced doctoral degree students.The goal of this work is to improve the fundamental understanding of flame stabilization and lean blowoff characteristics in bluff-body-anchored premixed flames in highly turbulent flow (with turbulence intensities up to 40% in the approaching flow and turbulence Reynolds numbers up to 8,100). An inverted conical flame configuration with a disk-shaped flame stabilizer will be employed. State-of-the-art laser diagnostics (particle image velocimetry and simultaneous planar laser induced fluorescence of hydroxyl and formaldehyde) will be utilized to measure the flame structure/flowfield interactions, enabling the understanding of high-turbulence combustion regimes that have not been fully explored before. The resulting experimental data will also be utilized for validation of high fidelity numerical simulations using large eddy simulation (LES) methodology. New experimental data for pre-vaporized liquid fuels are used to document and develop a comprehensive understanding of lean blowoff phenomena in premixed combustion as it relates to highly turbulent flow, bluff-body recirculation zone flow dynamics, and flame-flow interactions. These data will also include the flame properties in the higher turbulence regimes of corrugated flamelets and reaction sheets without the need for piloted flames.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.