Abstract: With water as atomizing medium，a experimental system is built based on the laser particle analyzer，and a series of experiments were conducted for two orifice diameter 0. 46 mm and 1. 44 mm under five different pressure respectively. Sauter Mean Diameter D ( 3, 2 ) ，Median Diameter D₅₀ and Volume Mean Diameter D ( 4, 3 ) ，which characterize atomization characteristic of the nozzle，are analyzed. Experimental data shows that the atomized droplets D ( 3, 2 ) ，D₅₀ ，D ( 4, 3 ) are reduced with increase of flux of water and pressure，standard deviation σ of the distribution of droplets becomes larger；At pressure 0. 28 MPa and flow 8. 5 L/h，the nozzle 0. 46 mm diameter obtains D₅₀ = 73. 24 μm of atomized droplets while 1. 44 mm diameter obtains D₅₀ = 84. 94 μm；The atomization effect of nozzle 0. 46 mm diameter is better than the 1. 44 mm diameter under the 0. 28 MPa pressure.

Key words: atomization characteristic, particle size distribution, atomization pressure, nozzle