Even in the presence of these obstacles, innovations in combustion science are impacting combustion engineering. Combustion, Flame, and Fire. Quite specific meanings are associated with the terms combustion, flame, and fire in the research community. Flame refers to the energy-releasing reaction between a fuel and oxidant which produces light, heat, and gaseous products. The fuel is typically a hydrocarbon while the oxidizer is generally air.
Fires are large uncontrolled flames.
We further classify flames in many ways. Depending on the fluid mechanics of the system, a flame may be classified as being either laminar or turbulent. In laminar flows, molecular diffusion drives the mixing between different points in the flow stream. Laminar flows mix rather poorly relative to turbulent flows where mixing is generated by the flow itself. In order to promote cleaner and more efficient flames, a significant amount of combustion research focuses on characterizing the effects of turbulence on flames as well as the effects of the flame on turbulence.