Why are Automist nozzles mounted on the wall instead of on the ceiling?
Sprinkler system nozzles are typically located on the ceiling. As a result, the large water droplets must drop with gravity and momentum against the upward buoyancy-driven flow created by the fire. Automist, through its sidewall delivery, utilises the turbulence created by the fire. Its lower position means the smaller droplet can be entrained into the fire plume instead of being lost in the hot layer above.
Archimedes' principle states that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces and acts in the upward direction at the centre of mass of the displaced fluid.
A water droplet should ideally evaporate inside the fire plume to be most effective in cooling and inerting the flames. If a droplet flows upwards together with the gases inside the plume, it will be in contact with the hottest part, evaporating fastest. If the droplet loses its upwards momentum inside the fire plume, it will fall back, driven by gravity. It is then possible to utilise the unevaporated droplet twice.