Experimental Study Of The Characteristics Of Effervescent Atomization

As a important technology in industry application and scientific research, atomizationtechnology has been widely used in fuel combustion, food processing, chemical industry,agriculture and other fields. Traditional atomization methods, such as mechanicalatomization, the energy consumption is high and the atomization effect is limited,especially for the liquid that has high viscosity. Effervescent atomization is effected onliquid surface tension that will have good applicability and high atomizatiion quality for theliquid with high viscosity. Effervescent atomization tiny oil gun is a typical exampleof successful applications of effervescent atomizing in energy industry. It has been widelyused in the ignition of coal-fired power plant. For diesel oil and other high viscosityliquid, effervescent atomization tiny oil gun can obtain ideal aerosol particle size anduniform distribution under the low pressure and low gas-liquid ratio conditions. Highcompleteness of Ignition burning, high heat utilization ratio and more efficiency.Therefore, this new type atomization—effervescent atomization has become themainstream direction of application and research.The effervescent atomization is related to gas-liquid two phase flow, so the flow fieldis complicated. The process and mechanism of effervescent atomization is temporarylacking. This paper has designed a new test bench for the character research of effervescentatomization. The test bench analyzed the key factors that influence cracking process andatomization quality of effervescent atomization by high-speed camera and laser particle sizeanalyzer. Adjusting the atomization pressure, gas-liquid ratio(GLR) and liquid mediumwhich are important parameters for atomization, to explain its influenceon effervescent atomization.The results showed that the unstable fluctuation of liquid which is caused by theinjected gas is the generation reason of effervescent atomization. The atomization processof effervescent atomization are following: After the gas mdium is injected into spray gun,the gas rings are formed from the nozzle outlet center to spray torch end. The gas rings areproducing, expanding and eventually broken, the rupture of gas rings make droplets cracked and atomized. Increase the atomization pressure can raise the jetvelocity and expand the atomization zone, also decrease the atomized particle droplet sizeand the particle-size distribution is more concentrated. The gas-liquid ratio(GLR) is themost important parameter that affecting the effervescent atomization. When GLR is high,the formation and cleavage of gas rings are more rapid, the atomization quality is betterthan low GLR conditions. When GLR is decreased, the average particle size increasedquickly and the particle distribution range would be enlarged, distribution uniformity ofparticle size is decreased. As the consequence, the atomization quality will be decreasedrapidly; The character of liquid medium has certain influence on cracking process ofeffervescent atomization. The liquid medium that has higher surface tension lead to largeraverage atomization particle size, and the distribution is not uniform; The atomizationangle is mainly affected by GLR. The character of atomized liquid medium has littleinfluence on the atomization angle.It had no significant changes when used liquid mediumswith different viscosity, density and surface tension under certain pressure and GLRconditions.