EFFECT OF IMPINGEMENT ANGLE ON DROP-SIZE DISTRIBUTION AND SPRAY PATTERN OF TWO IMPINGING WATER JETS

摘要

The spray formed by two 0-089-inch-diameter water jets was investigated for impingement angles of 10° to 90° and jet velocities of 30 to 74 feet per second. Photographs of the overall spray pattern formed in quiescent air show greater dispersion and reduced liquid sheet length for larger impingement angles. Jet-velocity effects were less pronounced.nDrop-size distributions were obtained with the spray formed in a 100-foot-per-second airstream. Drop counts were made from shadowgraph photographs using an electronic, particle analyzer. All distributions showed bimodal characteristics with number-median diameters of about 200 and 600 microns for the two modes. The most significant effect of impingement angle and jet velocity on the distributions was a change in the relative number of drops in each mode and the geometric mean deviation of the larger drop-size mode. An increase in impingement angle produced an increase in the number of small drops and a decrease in the deviation of the larger drop-size mode. This effect was most pronounced at low jet velocities. Mass-median diameters and relative mass in the two modes were determined from the basic number-size distributions, and the effect of angle and velocity was evaluated. At all test conditions the larger drop-size mode contained the majority of the mass.nOverall volume-number mean and mass-median drop diameters were obtained for each condition. Both parameters increased with a decrease in impingement angle, the largest increase occurring at low jet velocities.