Nozzle structure's influence on fuel flow oscillation in unsteady conditions

Assuming that fuel flow is continuous under small oscillation conditions, a correlation model about fuel flow oscillation and the nozzle structure was derived with flow number as an intermediate variable. Under this model, conclusion are made as follows: fuel flow oscillation is proportional to the flow number, and inversely proportional to the 0.5th power of average fuel pressure drop when the external excitation is given. Methods of decreasing fuel flow oscillation by decreasing flow number are obtained by nozzle calibration: increasing the throttling stage, decreasing throttling area. This method is validated through oscillation experiment. A general design procedure is suggested for nozzle designers in face of the instability problem. ©, 2015, BUAA Press. All right reserved.