Breakup of turbulent liquid jets in still gases

Abstract

An investigation of the breakup lengths of. turbulentliquid jets in still -gases is described. Different ~breakup modes were visualized and mean and fluctuating breakup lengths were measured for round turbulent free jets of water and ethanol in still air at standard temperature and pressure. Jet exit conditions were limited to non-cavitating flows with long length/diameter ratio constant area injector passages and jet exit Reynolds numbers of 6,000140,000, Two turb.ulent liquid column breakup modes were observed: a turbulent primary breakup ,, mode observed at small Weber numbers and a bag/shear breakup mode observed at large Weber numbers. The turbulent primary breakup-mode was successfully associated with existing theories of this process as the condition where drop sizes resulting from turbulent primary breakup are comparable to the diameter of the liquid column itself. ,The bag/shear breakup mode was observed when liquid turbulence caused large deformations of the liquid column, placing portions of the column in cross flow; this caused bag or shear breakup of the liquid column as a whole which was successfully associated with existing theories of bag and shear breakup of nonturbulent round liquid jets in cross flowing gases.