Air pressure - snowmaking

From FIS Freestyle wiki

Air Pressure

Air/water snow nozzles atomize the flow of water by introducing a high velocity differential between the water and compressed air phases. This velocity differential induces surface perturbations in the water jet, which provides energy to overcome surface tension and effectively shatters the fluid. By increasing or decreasing the flow of compressed air, the velocity differential between air and water can be adjusted, creating a method by which droplet sizes can be altered.

Most ski resorts supply their snowmaking equipment with a compressed air pressure of 80 to 100 psi (550 to 700 kPa). In recent years, a few resorts have elevated this compressed air pressure to 150 psi (1000 kPa).

Because droplet size in a snowmaking type of atomizer is inversely proportional to air pressure, this creates a spray with a smaller mean droplet size. However, the energy cost of compressing air to 150 psi is increased by 40%. There is disagreement within the ski industry whether this added expense pays off (Barthold, 1986)