RT Journal Article ID 187ace9b56b717ce A1 Lee, Chang Sik A1 Reitz, Rolf D. T1 EFFECT OF LIQUID PROPERTIES ON THE BREAKUP MECHANISM OF HIGH-SPEED LIQUID DROPS JF Atomization and Sprays JO AAS YR 2001 FD 2001-02-01 VO 11 IS 1 SP 1 OP 19 AB The breakup mechanisms of liquid drops in high-velocity air flows were studied. Ultra high-magnification, short-exposure photography was used to analyze drop breakup in three drop breakup regimes previously referred to as the bag breakup regime, the "shear" or "boundary-layer stripping" breakup regime, and the "catastrophic" breakup regime. Diesel fuel and water were used as the spray liquids, and the air gas pressure was varied from atmospheric up to 0.6 MPa at room temperature to avoid liquid vaporization. In the experiments the drop Weber number was varied between 78 and 476, and the drop Reynolds number was changed from 1046 to 9327. The results show that the breakup process is primarily influenced by the value of the Weber number in all three breakup regimes. Consistent with an earlier study of Liu and Reitz [1], the present results further question the validity of the widely used "shear" or "boundary-layer stripping" drop breakup theories, which ascribe the breakup mechanism of high-speed drops to viscous stresses at the gas-liquid interface. Instead, the present results indicate that high-speed drop breakup is due to distortion of the drops and the formation of thin liquid sheets at the edge of the flattened drops. The liquid sheets are stretched and bent by the air flow and form ligaments that ultimately break up into droplets. The shape and length of the ligaments depend strongly on the liquid surface tension coefficient. The breakup mechanisms of drops with the different liquids were found to be similar at atmospheric and elevated ambient pressure conditions provided that the Weber number was the same. However, under "catastrophic" breakup conditions the secondary breakup of the filaments or ligaments was accelerated at high gas density. PB Begell House LK https://www.dl.begellhouse.com/journals/6a7c7e10642258cc,009f021e439250d7,187ace9b56b717ce.html