Effect of flow rate on the spray characteristics of impinging water jets

Abstract

An experimental study of the spray characteristics of impinging, turbulent water jets is conducted using a phase Doppler particle analyzer (PDFA). Both two and four impinging jet injectors are examined. The Reynolds number of the jets is varied in the range 3000 < Re < 7500. Detailed distribution of diameter, velocity, number density, and volume flux for each case is reported. For the injector with two jets impinging on each other at a 90 deg angle, mean drop size reduces, and mean velocity and number density increase as the jet velocities increase. The volume flux may increase or decrease, depending on the location on the cross section of the spray. The four impinging jet injector is made up of two parallel jets at the center and two other side jets, at the same plane, impinging on them at a 45 deg angle. For this injector, as the flow rate of two parallel jets increases, a critical flow rate is obtained, below which the mean drop size and velocity increase and above which they decrease.