The Droplet Size Change In SLD Water Droplet Collision

In the development of aircraft and engine,ice security verification is one of the important and difficult thing.The freezing experiment in icing wind tunnel is the most important research technique.The particle size distribution is an important parameter in the experiment of the simulation of SLD cloud.In 2014,FAR department launched appendix O and put forward the requirements of supercooled large droplets airworthiness(SLD)environment which provided the cloud size distribution of freezing environment.The particle size distribution of cloud droplets is mainly affected by the collision process and different collision result will change droplet number,size and speed.Nowadays the research of particle size evolution in the icing wind tunnel in the world are still based on the results of room temperature water droplets collision which has a greater difference with cold temperature.The icing wind tunnel do not implement the appendix O environment experiment ability.So the study of SLD water droplet collision phenomenon is of great value to study the particle size distribution of SLD environment.The experiment of the SLD water droplet collision is designed for studying the process of SLD collision and the results are compared with the results of room temperature water droplets collision.The research process is that the supercooled water droplets collision is studied under different temperatures water droplets including the conditions of collision outcome and the state of the water droplets change after the collision,and the collision results of room temperature is compared.From the perspective of the supercooled water properties,the influence of the temperature on collision results are discussed,combing the theory of surface tension and viscosity of SLD droplets.The experiment also studied different diameter droplets collision results and the water droplets change after the collision.The innovation points of this article are that the SLD water droplets collision is studied through experiment and was compared with the result under the condition of room temperature;the influence of the temperature and particle size on SLD water droplet collision are discussed in this paper,the particle size change after SLD droplets collide is put forward which has significant meaning for guiding the simulation of SLD cloud environment.