Experimental Study Of Bubble Growth And Motion Characteristics In Down Round Heated Wall

Since the boiling heat transfer involving many engineering fields. Such as:boiling heat transfer in quenching process of materials processing and the evaporator steam generation process,therefore it’s mechanism has been studied extensively for nearly a century.Nevertheless, there are also many scientific problems that have not been resolved completely. For the phenomenon of bubble’s generation,growing,jumping off and rising on the upward horizontal and vertical surfaces that have been studied far more and detailly,compared with that less report on the bubble’s dynamical behavior and caloric-transference below the curved surfaces.In this paper,through the technology of high-speed photography that coordinate with digital image which has the function as disposition and analysis, we study the nucleate boiling bubble’s characteristics of growth and motion on the curved wall,and achieve their regular pattern preliminarily,such as deformation, slip and speed change.The mainly research has been shown as follows:(1) To design and build a visual bench. Through comparing a variety of materials of metal pipes,we choose stainless steel as the material of immersion tube;Through comparing a variety of light sources, iodine nickel filament lamp be chosen as the background light for shooting;Consider about the higher temperature of the liquid in the experiment,we select the tempered glass to make the tank.(2) We program compiler various of methods for image disposition with Matlab.By comparing with the other results, the method of imadjust be chosed to deal with these pictures. Finally, using Image Pro Plus software to analyse the relevant parameters of the bubble in the images.(3) Using Tecplot to plot intuitive curve with the resulting data above and identify various of bubbles’regular pattern of relevant parameters which in different conditions(4) The experimental results show that:The process of bubble’s campaign along the arc surface that has not always been closed to the wall, instead,move away from the wall after the moment of movement; Bubble growth in the bottom of the curved wall be influenced by the heat flux, as a result,the more the heat flux the greater equivalent diameter before bubble begin to exercise; As the same,the growth of the bubble in the bottom of the curved wall, the more heat flux the greater motion angle when it move away from the wall;When we deal with bubble close to the wall by Matlab software,the imadjust could receive better results;...