Experiments on Turbulence-Chemistry Interaction in Highly Turbulent Counterflow Flames

Yale University, New Haven CT

Investigators

Abstract

Proposal: 1403433 PI: Gomez, Alessandro Title: Experiments on Turbulence-Chemistry Interaction in Highly Turbulent Counterflow Flames The proposal focuses on understanding how energy transfers occur in flames that are seen in practical burners such as power plants and jet engines. A model flame, established by using the so-called counterflow burner, serves the purpose for investigation in a university laboratory, aiming to translate the knowledge gained into practical burner systems. Advanced laser-based tools will be used in conjunction with a high-speed camera to visualize phenomena that are not seen by regular cameras and human eyes and that are of significance for understanding these flames. The proposed research is leveraged with collaborations with Sandia National Laboratory and Cornell University, where computer modeling of these flames will be pursued. The proposed study will focus on the assessment of the energy transfer across scales in highly turbulent counter-flow flames. Turbulent kinetic energy is generated at large scales, transferred down in a cascade over a broad range of scales and eventually dissipated at the smallest scale. Highly turbulent counter-flow flames will be used as a benchmark configuration for this type of systematic experimentation. They offer significant advantages, such as: flame stabilization without a pilot at high Reynolds numbers; compactness, with significant advantages for highly resolved computations; and versatility, with the ability to access a broad range of combustion regimes, especially those of industrial relevance. The objective is to quantify this energy transfer and contrast it in the non-reacting case with the reacting counterparts, under both non-premixed and premixed conditions. A filter-space technique will be applied to a three-dimensional set of velocity measurements. After initial tests at Yale to identify the most interesting flames, the bulk of the measurements will be performed at Sandia National Laboratories by relying on a newly acquired facility for high-speed imaging that will provide simultaneous tomographic PIV and planar laser-induced fluorescence measurements at high repetition rates. The proposed research is leveraged with collaborations with Sandia and Cornell University, where modeling of these flames will be pursued. The proposed activity also has a computational component developed at Cornell that is validated using these experimental data. The high quality database, including well-characterized boundary conditions, will be made available on the web to the combustion community for further modeling within the framework of ongoing international collaborations.