Experimental Study On Gas Entrainment By Vortex In Stratified Flow Of Horizontal Tube

Free surface vortex is a common phenomenon in daily life and production.There is a swirl can lead to a reduction in pump output.In addition,strong Free-surface vortices can suck floating material,garbage and air into the suction pipe,causing damage to the rotating parts of the hydraulic unit.Because of its importance,in the past 50 years scholars have conducted in-depth research on the gas carrying problem.In this paper,the phenomenon of gas being inhaled by the vortex in the stratified flow of horizontal pipe gas and liquid is studied by experimental method,and the gas carrying process and optimization method are studied in depth.The main research contents and conclusions of the research obtained are as follows:By constructing a visualized test bench for vortex suction gas in horizontal tube gas-liquid stratified flow,the gas carrying experiments under different working conditions were carried out.A high-speed camera was used to collect the image of the vortex shape and its development on the Free liquid surface in the horizontal tube.Visual observation shows that there are three stages in the form of vortex when gas carrying occurs:the stage of liquid level stabilization,the stage of vortex core emergence,and the stage of vortex core development.In the development stage of the vortex core,the lower end of the vortex core may have lost its stability and dissipated before reaching the suction pipe mouth,or the lower end of the vortex core may reach the suction pipe mouth,resulting in gas carrying.These two phenomena happen at random.Under the condition of fixed liquid level,the flow rate is gradually increased,and there is a certain flow rate,so that the generated vortex can carry air into the suction pipe.The study shows that the factors such as suction pipe flow rate,system operating temperature and operating pressure have been proved to have important effects on the process of vortex gas inhalation in gas-liquid stratified flow.On this basis,Fr is selected as the independent variable and the dimensionless critical level Hc/d as the dependent variable,and a new experimental correlation formula for critical level is proposed.(2)On the basis of experiments with main pipe diameter of 285 mm,branch pipe diameter of 80mm,and main branch pipe included angles along the direction of flow and circumference of 90°,gas carrying experiments were conducted under three conditions,namely,different pipe diameter ratio,included angles along the direction of flow of different main branch pipes,and included angles along the circumference of different main branch pipes.The difference of diameter ratio between suction pipe and main pipe and the Angle between main pipe and branch pipe along the flow direction have no obvious influence on the vortex shape and critical liquid level.The circumferential Angle between the suction pipe and the main tube has obvious influence on the vortex morphology.Due to the influence of the wall surface and the height of the Free liquid surface,the vortex has a greater probability of approaching the inner wall surface and then dissipating,and the duration is also significantly shortened.In this sense,the circumferential arrangement of the suction pipe can make the development of the vortex difficult,which is conducive to avoiding the occurrence of gas carrying.However,From the distance From the critical level to the bottom of the main pipe,there is no obvious advantage in the circumgyrate inclined arrangement.