Unsteady Multidimensional Simulations of the Structure and Dynamics of Flames

The primary objective of our research is to develop an understanding of the differences in the structure, stability, dynamics and extinction of flames in earth gravity and in microgravity environments. Numerical simulations, in which the various physical and chemical processes can be independently controlled, can significantly advance our understanding of these differences. Therefore, our approach is to use detailed time-dependent, multidimensional, multispecies numerical models to perform carefully designed computational experiments. Some of these computational experiments are also complementary to physical experiments performed under the Microgravity Combustion Science Program. In this report, we provide a brief summary of our research since the last microgravity combustion workshop. The two major projects we have been working on are: (1) the development and application of a three-dimensional, time-dependent flame model, and (2) a study of the effects of gravity on flame-vortex interactions. A state-of-the-art parallel flame code, FLAME3D, has been developed and used to simulate the three-dimensional cellular structure of lean hydrogen flames. The results from the simulations have been compared to our previous two-dimensional simulations to understand the role of three-dimensionality. This is discussed below in some detail after a brief discussion of the flame code. The second project deals with flame-vortex interactions under different gravitational environments such as zero, upward and downward Earth gravity. These numerical experiments are complementary to the physical experiments of Driscoll et al reported elsewhere in these proceedings.