FLUID SHEET THICKNESS AND VELOCITY AT THE TIP OF A BLACK LIQUOR SPLASHPLATE NOZZLE

The fluid sheet thickness and velocity at the tip of a spray nozzle have previously been identified as being important to the ultimate droplet size distribution. In this investigation both the fluid sheet thickness and the velocity of the top surface just beyond the rim of a splashplate nozzle have been measured as functions of nozzle exit velocity and fluid viscosity. Measurements were made on two Babcock & Wilcox Co. splashplate nozzles, a 12-49 and a 15-52, specifically designed for black liquor, a by-product of wood pulping. Comparisons of the ratio of the sheet velocity to the nozzle velocity are shown to be very similar to previous data for the ratio of droplet velocity to nozzle velocity. Likewise, the dependence of the sheet thickness on nozzle exit velocity closely matches the previously measured dependence of the ultimate median droplet size on nozzle exit velocity. Both of these results are consistent with current theories of droplet formation mechanisms. Analysis of continuity and viscous drag on the splashplate are used to develop correlation equations for the data