A cylindrical rotor is rotatably mounted within the bore of a housing. A plurality of passages arranged in concentric annular rows extend through the rotor. Each passage is generally rectangular in cross section and is inclined with respect to the axis of the rotor. The rotor is forced to rotate in response to a gaseous stream moving through the bore and the passages. Liquid particles entrained within the gaseous stream are atomized in response to the movement of the rotor.