Experimental investigation of geometric scaling on atomization in a two-phase gas/liquid spray

In this study the atomization performance of a full-scale industrial air-liquid nozzle is compared to a one-quarter model. The objective is to establish a global Sauter mean diameter D_32(gb) correlation as a function of nozzle size (D) in a two-phase gas/liquid (TPGL) spray atomization. This information is to be used in the design and development of nozzles for heavy oil upgrading industry. Compressed air was used as the gas phase; the liquids were water, canola oil, and glycerine solutions all at room temperature. The liquid flow rates were varied from 0.095 to 0.195 L/s, and the gas-to-liquid-ratio (β), by mass, was fixed at 1%, similar to commercial fluid coker nozzles. Fluid mixing pressures in the test were between 516 and 1000 kPa. The D₃₂within the spray was measured using a Dantec 2-D phase-Doppler particle anemometer (PDPA) with measurements performed at axial distances of 100, 202, and 405 mm from the nozzle exit and within spray widths of +50 to -50 mm in the horizontal plane. Experimental results show that if the D is increased from 3.1 to 4.1 mm (1.3 times), D does not show a change on D32 and equates to the power of 0.1 (glycerine solution sprays at μL = 67 mPa s) to 0.9 (water sprays at μL = 1 mPa s). Finally, the D _32(gb)correlation as a function of geometric scaling estimated drop size within a 17% maximum deviation between the experimental and curve fit data.