Numerical And Experimental Research Of Dynamic Characteristics Of Nozzle Spray

In the traditional sense, during the design of the nozzle of gas turbine,liquid rocket engines, boilers and other power equipment, nozzles areconsidered working under stable pressure. In fact, acoustic oscillations in thecombustion chamber and fuel injection devices often generate pressurepulsations, which would cause a change of nozzle performance, and thischange is called dynamic characteristics of the nozzle. Dynamic characteristicsof the nozzle has a great influence on the combustion performance, and adetailed understanding of the dynamic characteristics contribute to thedevelopment of the technique that use nozzles as control device to control thecombustion process. Therefore, it is necessary to understand the dynamiccharacteristics of the nozzle. In detail, it is the study of the nozzle flow, sprayangle, the gas-liquid distribution characteristics under fluctuating pressure.the mass flow was analyzed under the pulsating pressure condition. The resultsshow the spray angle and mass flow fluctuate at the same frequency with thepulsating pressure. The average mass flow approximates the designed massflow. The amplitude of the mass flow first increases and then decrease with theincrease of the frequency, and reach the maximum value at400Hz.The phasedifference between outlet mass flow and inlet pressure increases linearly withthe pressure frequency, and the fluctuating pressure amplitude has little effecton the phase difference.Characteristics of the study in the downstream nozzle spray field underfluctuating pressure gas-liquid two-phase distribution, planar laser inducedexciplex fluorescence technique can be used to measure gas-liquid two-phasedistribution of fuel oil. Fluorescence characteristic experiment of TMPD/Np exciplex was conducted, and the effect of concentration of the tracer andtemperature on the PLIEF was analyzed. The results show the concentration offluorescencing tracer influences the fluorescence intensity of moner andexciplex, and relative high concentration of Np should be used. Temperaturealso has an effect on the PLIEF, and temperature of measuring space should bebig enough or the measured liquid phase distribution would be bigger than thereal situation.In order to measure the gas and liquid phase fuel distribution underpulsating pressure in the hot state, the design calculation and CAD part andassembly drawings of the model combustor were done.