Cool Flames Investigation with Gases (CFI-G)
Cool diffusion flames were discovered during droplet combustion experiments aboard the International Space Station (ISS) in 2012, and this initiated a rapidly growing field of combustion research. Droplet experiments necessarily involve unsteady burning rates, so cool diffusion flames have never been observed as steady spherical flames. A natural progression toward understanding cool diffusion flames is to observe quasi-steady spherical flames on porous burners, and this is the topic of this research. The flames to be studied are rich in the physics and chemistry of combustion and thermal transport processes.
- Principal Investigator (PI): Peter B. Sunderland (U. of Maryland, College Park, MD, USA)
- Co-Investigator (Co-I): Richard L. Axelbaum (Washington U. in St. Louis, MO, USA)
- Co-Investigator (Co-I): Forman A. Williams (U. of California San Diego, CA, USA)
ISS TESTING TIMELINE
- 2009-2017: Droplet combustion experiments in which cool diffusion flames were discovered and which culminated in the Cool Flames Investigation (CFI) with droplets of liquid fuel
- 2021 March–Spring: Round 1 featuring normal flames where gaseous fuel will flow out of a porous spherical burner
- 2021 Summer: Round 2 featuring inverse flames where the combustion chamber will be filled with a mixture of gaseous fuel and nitrogen and an oxygen/nitrogen mixture will flow out of a porous spherical burner
- RELEVANCE: Most internal combustion engines are designed using computer models that neglect cool flame chemistry, but ignition and flame propagation in engines depend on cool flame chemistry. Cool flame chemistry also has a significant impact on fuel octane and cetane numbers, whose understanding has large economic consequences.
- MICROGRAVITY: The flame system to be studied will allow steady spherical cool diffusion flames to be observed for the first time. The tests, performed with gaseous fuel and a porous spherical burner, cannot be performed in normal gravity or in ground-based microgravity facilities.
- MODELING: Observing cool flames burning as steady spherical diffusion flames will yield valuable insight into cool flame chemical kinetics. An advanced Computational Fluid Dynamics (CFD) model will simulate the flames and will aid the testing and development of cool flame kinetics models.
- SHARING OF RESULTS: The research will be disseminated widely to the combustion research community and to industry. It should advance the state-of-the-art in cool flame kinetics mechanisms, which in turn could lead to cleaner, more efficient internal combustion engines.