Atomization

Atomization is the step that turns liquid fuel into a cloud of droplets. Combustion can only take place at the surface of a droplet, so the smaller the droplets, the faster the fuel evaporates and the shorter the flame. Poor atomization shows up as soot, high CO and unburned hydrocarbons.

Four mechanisms are used in oil burners. Pressure (simplex) atomization forces the fuel through a swirl chamber and lets the pressure energy break the film. Spill-back atomization uses the same chamber but modulates the returned quantity. Disc or plate atomization distributes the flow over several stacked orifices for very large outputs. Air and steam atomization adds a second fluid whose shear supplies most of the break-up energy.

Which mechanism is right depends on the required turn-down, the available atomizing medium and the fuel. Fluid Control Instruments Ltd covers all four, from 0.5 kg/h residential nozzles to 5000 kg/h industrial atomizers.