Experimental Research On Bubble Formation And Its Size Distribution In Vibrating Liquid

The phenomenon of bubble production in vibrating liquid is closely related to many fields in nature and industry.With the development of science and technology,studies of bubble phenomena in vibrating liquids are also reaching new stages.So far,the study of bubble dynamics and vibrating liquid surface waves in vibrating liquids has been a hot topic in this field.Most of the researches are confined to the phenomena of bubbles produced by droplets impacting on quiet liquid surface and the phenomena of waves on vibrating liquid surface.However,there are few studies on the process of bubble formation and the bubble size distribution in vibrating liquids.Using high-speed camera technology,this study designed the experiments on spontaneous production of bubbles in vibrating liquid.The process of bubble formation and the size distribution of bubbles in the vibrating liquids are recorded.The path and mechanisms of the bubble formation in the experiment are analyzed and the relationship and difference between the droplet impact in the condition of the quiet liquid surface are also studied.This study also summarized the characteristics of the size distribution of bubbles in vibrating liquids and the affecting factors,which is helpful for further exploration of gas-liquid phenomena in vibrating liquids.The main contents of the thesis are as follows:Chapter 1 introduces the research status of droplet impact and the phenomena related to liquid surface waves and internal bubbles.The achievements and progress of domestic and foreign scholars in these fields are discussed.This chapter also summarizes the characteristics and mechanism of these phenomena from the studies at home and abroad.And on this basis,the significance and content of this thesis are expounded.Chapter 2 proposes the scheme for experimental studying on the bubble formation and distribution in vibrating liquid.Based on the actual experimental conditions,we design and build the experimental setup system for completing the research.We choose and determine the experimental method and technology,design the detailed experimental process and setup,and obtain the expected experimental results.Chapter 3 analyzes the data obtained by the experiments.In this chapter,we study the critical threshold of bubble formation in vibrating water and find the effects of the vibrational factors on the bubble formation.We also analyze the characteristics of the bubble size distribution curves and the change of the Sauter-mean diameter with time in vibrating liquid.The influences of the vibrational elements and viscosity of liquids on the bubbles size distribution are studied.The bubble size distribution curves are fitted and the law of its distribution in vibrating water is found in this chapter.Chapter 4 studies the phenomena of bubble formation on the vibrating liquid surface.According to the captured images of dynamic bubble formation process on the surface of vibrating liquids,the sources of bubble formation are classified and summarized.We analyze the dynamic process and mechanism of various bubble producing types.Comparing with the drop impact on the quiet liquid surface,the different phenomena of bubble formation on the vibrating liquid surface are discovered.This chapter analyzes the bubble size characteristics of different producing mechanisms and the law of the bubbles size distribution is explained.Chapter 5 summarizes the main content and achievement of this thesis,and the follow-up work and direction of this topic are prospected.