Study On Melting Characteristics Of An Icicle In Low-temperature Water Flow

Water,as an important solid-liquid phase energy storage material,has attracted extensive attention due to its coupling of latent heat and phase interface movement during phase transformation.It is particularly important to study the melting rate and shape evolution of water during phase transformation to improve the efficiency of melting ice and study the evolution process of icebergs.In this dissertation,the melting of icicle under uniform low temperature is studied by using computational fluid dynamics,and the melting characteristics,shape evolution and influencing factors of two-dimensional icicle melting are discussed.The main research contents and achievements are as follows.(1)The characteristics of melting law and shape evolution of two dimensional circular icicle melting have been studied.By studying the melting law of round icicle,the relative size of the circular icicle decreases with time in an upward concave conic curve.With the increase of Peckelet number,there are three different terminal shapes of circular icicle: ellipse with arc-shaped shape on both sides of left and right,circular shape on the left,semicircle on the right,convex structure with circular shape on the left and concave middle arc on the upper and lower ends on the right.(2)The influence of different incoming flow velocity,incoming flow temperature and initial icicle temperature on melting of circular icicle has been studied.An analysis of the factors that influence the melting of icicles,with the increase of Peckler number or Stephen number,the melting rate of the circular icicle increases obviously,but the trend of melting rate decreases under the condition that the physical properties of the ice-water two phases are not changed.Changing the ratio of temperature difference between solid and liquid phases has little influence on the melting rate of circular icicle.The shape evolution of the circular icicle shows three different terminal shapes with the increase of Peckler number before the end of melting.However,the stephan number and the ratio of temperature difference between solid and liquid have little influence on the terminal shape of the cylinder.(3)The shape changes of icicle with square and rhombus shapes during melting have been studied.The research shows that the terminal shapes of icles with different initial shapes have the same self-similarity,and the shape is only related to the size of Peckelet number,but the boundary of peckelet number corresponding to the three terminal shapes formed by the melting of icles with different initial shapes is different.