g-Jitter effects on spherical diffusion flames

• Published in: Microgravity science and technology Vol. 15; no. 4; pp. 12 - 30
• Main Authors: Mell, William E., McGrattan, Kevin B., Baum, Howard R.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Nature B.V 01.12.2004
• Subjects: Computer simulation; Experimental design; Studies
• ISSN: 0938-0108; 1875-0494
• DOI: 10.1007/BF02870965

Acceleration disturbances or g-jitter exist in all reduced gravity experimental platforms. These disturbances often have a fully three-dimensional orientation and are transient. An important element in experimental design, therefore, is a determination of how sensitive the physical processes under investigation may be to the expected g-jitter. Very few experimental studies exist that are focused on quantifying acceptable levels of g-jitter due to their expense and the wide range of relevant parameters. A three-dimensional fully transient computer simulation approach was developed, validated, and used to assess the potential that a given acceleration disturbance will have an unacceptable influence on spherical diffusion flames. An emphasis was put on computational efficiency resulting in the use of a simple, mixture fraction based, combustion model. Given the limitations of this model the simulation provided accurate predictions of flame behaviour in experiments conducted in NASAs drop tower and aircraft reduced gravity platforms. Spherical diffusion flames in acceleration environments characteristic of the International Space Station were also simulated. The results implied that a passive isolation system combined with appropriate scheduling of crew activity would provide a sufficiently disturbance free environment for spherical diffusion flame experiments.[PUBLICATION ABSTRACT]