An Experimental Study On The Spray Characteristics Of The Air-blast Atomizer

Nozzle as a common device in various of fields are widely used in industrial, agricultural and some other fields which need to change the liquid into droplet to achieve the purpose of atomization. It carries a variety of tasks, such as humidification, spraying, burning, etc. Air-blast atomizer is a kind of nozzle and has been widely applied in aviation. With the help of high-speed air it makes the aviation kerosene film fracture into droplet and achieve good atomization. A good atomization can make the aviation kerosene mix with air better, increase the combustion efficiency and reduce emissions.In order to investigate the influence of different mixing modes and pressure variations on the spray characteristics of air-blast atomizer, in terms of two air-blast atomizers with different mixing modes, a series of experiments was conducted by using of the laser induced fluorescence (LIF) and particle image velocimetry (PIV) system. The effects of liquid pressure and air pressure on the spray angle and particles velocity are studied and analysed.The mainly research has been shown as follows:(1) Design and built spray visualization system. Select and buy air compressor, high pressure oil pump, flowmeter, pressure gage and other equipments. Buy uv fused silica glass and then make spray dark room.(2) Select the single pulse and double pulse laser and sheet optics as the light souce of the measurement system. Using the PTU, Long pass filter, CCD camera and some other equipments to collect the image. Design the experimental scheme.(3) Carried out the experiments according to the scheduled program and collect the data. To reduce error it needs to do denoising processing for many times. Calculate the spray angle and velocity by using the software. Using the software Tecplot to sort data and plot.(4) The results indicate that for both atomizers, the spray angle and particles velocity are not sensitive to the liquid pressure, but they are significantly affected by the air pressure. Specifically, with the increase of the air pressure, the spray angle of A atomizer increases firstly, and then it decreases. As for B atomizer, at first, the spray angle increases then it maintains as a constant. Under the same liquid pressure, the velocity of the particles of A atomizer increase obviously with air pressure, but no eddy has been formed. As for B atomizer, as air pressure increases, the particles velocity increase, and lots of eddies are formed, which demonstrates that under the same condition, the mixing mode of B atomizer can make the mixture of air and liquid more uniformly with better spray characteristics.