Lets say there is a fire on a zero-g space station (no efforts have been made to give gravity to the structure and it's far enough away from any planet/sun that gravity is negligible). It is contained and does not breach any of the structure itself (so ignore the vacuum elements here). For simplicity, lets assume it's a candle sitting in the middle of a contained room (no air is entering and air circulation is minimal). Assume 'air' has the standard earth like composition.
2 part question:
Heat rises on Earth as the hot air is significantly less dense than cool air. A flickering flame flickers upwards for the same reason. However in a zero-g environemnt, there really is no up. So what does a zero-g flame visually look like?
Heat rising also fuels the fire by dragging in more oxygen as the hot air rises giving room for new oxygen rich air to move in behind it. Without this cycle, to fuel itself and without some other mechanism to cycle the air, how long would a fire feasibly burn for? Would it consume all the oxygen in a room before burning out, or would it simply consume the oxygen in the immediate area around the flame and burn itself out before the oxygen in the room is fully consumed?
And an extention to #2 - would it be possible that the fire would sit in a state where it's ready to ignite the second enough oxygen was present (or very slowly burn as the remaining oxygen in the room diffuses)?