Effect of pressure and temperature on oil mist sprays used for blade excitation in high cycle fatigue testing

Abstract

The flow patterns of two oil mist nozzles used in rotor blade excitation experiments were characterized using a Laser Doppler Velocimeter (LDV). Both nozzles were operated in a vacuum test chamber and velocity measurements were taken at three axial distances from the nozzle exit, at three or four different pressures, at three different temperatures. The 4 gallon per hour "mini-mist" nozzle produced a "referenced velocity" consistent with a hollow cone at each axial location, pressure, and temperature. The temperature of the oil flowing through the 4 gallon per hour nozzle did not affect the nozzle's performance. The 6 gallon per hour "standard" nozzle produced a "solid" cone structure at each axial location, pressure, and temperature. The temperature of the oil flowing through the 6 gallon per hour nozzle did affect the nozzle's performance. The spray pattern quantification can be used to design blade excitation experiments in high cycle fatigue (HCF) vacuum spin tests.