Experimental Research Of Droplet Impacting Onto High Temperature Steel Plate Surface

Droplet impact phenomenon widely exists in industrial fields such as metallurgy,chemical industry and the spray coating, belonging to the typical free surface flowphenomenon. Impact phenomenons is different according to the different properties ofdroplet and the impact surface state. Because of the complexity of the process of dropletimpact in reality it is difficult to conduct a comprehensive and detailed description, soresearch of single droplet impact is important method to reveal heat and mass transferand fluid flow characteristics of liquid on the solid surface. With the development ofscience and technology, high speed imaging technology is widely used in droplet impactphenomena. Research of droplet impact phenomenon is positive to explain the realphenomenon and improve production technology.The single droplet impact is researched onto the high temperature steel platesurface with high-speed imaging and image processing software. Piezoelectric resonantcavity droplet generator produce different diameter and different speed droplets withruili theory,and the droplet size is measured using the oil film method and measuredthe droplet velocity under different pressure for different aperture nozzle.The droplets isthe deionized water.The impact surface(2520stainless steel) temperature is23-900℃. Images is measured by IPP software to obtain experimental data and analyse thephenomenon. Droplet velocity, droplet diameter and the steel plate temperature isMainly explored for influence on droplet impact and to get empirical equation.The experimental results show that droplet begin rebound when impacting onto300℃steel plate surface and occur leidenfrost phenomenon. Largest spreading factorincreases with the increase of weber number. droplet impact happens brokenphenomenon when weber number We=39.3on400℃surface, as a critical statebetween rebound of shrinking and the fast splash. Weber number has a weak influenceon the time of droplet spreading,but it has a strong influence on shrinkage and rebound. The influence of droplet velocity on the spreading factor is greater than the droplet sizeas the same We.When the temperature is higher than leidenfrost temperature, it appearsmall droplet splash phenomenon. Superheat of steel has a weak influence on dropletspreading factor,due to the formation of gas film between the solid surface and liquid.