Experimental Study On The Atomization Characteristic Of Pressure Swirl Nozzle With Backpressure

Spray nozzle is utilizing in many fields,especially in combustion equipment.It has been an indispensable part of many kinds of combustion equipment.In many combustor chambers of power plant,fuel atomization directly affect the quality of mixture gas and is a significant factor of the economic performance,dynamic performance and emission levels of the power plant.The working environment of combustion nozzle has very high backpressure.It can affect the nozzle’s atomization significantly,so the research on the effect of high backpressure to atomization is very important.In this paper,a test facility is specially designed for the backpressure of the nozzle’s atomization.This test facility can provide a stable backpressure for the spray nozzle,and automatically realize the date collection and measurement system.Some experiments are done to investigate the atomization of spray nozzle in some certain backpressure,in order to show how the backpressure and pressure-difference affect the mass flow,atomization angle and the average diameter of atomization particle.In this paper,method of Active Contour Model is used in the processes of boundary extraction and spray angle calculation.A Graphical User Interface program is made for users to calculate the spray angles expediently.This paper designs a pulse laser measuring instrument,and does a series of experimental researches on the reliability of the instrument.Finally,the atomized particle size is measured with this device.In this paper,the spray nozzle runs in the atmospheric environment and runs with backpressure in the cylinder designed separately.Comparing the experimental results,it shows: the backpressure does not affect the mass flow much;the atomization angle will decrease when the backpressure increase,and then becomes some stable value,while the pressure difference does not affect it much.With the backpressure,the distant that the nozzle atomization becomes stable is reduced sharply and the average diameter will increase notably.When analyzing the experimental results with backpressure,it shows that near the nozzle the diameter of particle is decreasing with the backpressure increasing in the same pressure difference.When far from the nozzle,the diameter is increasing with the backpressure increasing.With low backpressure,in different pressure difference there are obvious difference in the particle’s diameter with the same distance from the nozzle.However,when the backpressure increases to some certain value,the pressure difference does not affect the average diameter of atomization particle.