Natural Circulation System Vapor Lock Formation Mechanism With The Smallest Inclination

Natural circulation system is widely used in many industrial fields, especially for nuclearpower utilization, boiler circulation, and solar energy usage. Two phases gas-liquid flowingis common in the natural circulation system. However, when the gas couldn't get throughthe system smoothly,bubbles resistances are created. It is necessary to offer both some rulesabout how the bubbles resistances appear and some proper solutions to guaranteenormal&safe applications for the natural circulation system.In the common open natural circulation system, because of the influence of theself-volume,liquid and pipe-wall when outside-air go into the system it will grow, gatherand move, etc. theoretically and experimentally, This paper researches on how thesingle-bubble moving and why the bubbles resistances in the circulation pipes of thecollector forming by the example of the solar power water heaters, this study achieves theequation of the critical inclined angles which could avoid bubbles resistances.By the experimental observing, this paper gets the shape of the single-bubble in theinclined pipe with small angle. By the theoretical reasoning, this paper gets the growingcharacteristics of the bubbles before and after breaking away in the inclined pipe with smallangle. This paper also makes brief studies of the terminating moving velocity of the bubblesand the gathering of the bubbles. At last this paper makes a judge of the flowing shape ofthe fully developed flow in the pipe.This paper makes a mechanical analysis of the deformed bubbles in the inclined circinalpipe with small angle (ICPSA), establishes a linking mechanical model. Based on themechanical model, this paper confirms the critical condition in which bubbles resistanceshappen and gets the critical angle equation of the waiting-to-solve parameters,whichcould avoids the bubbles resistances. By studying the bubbles in the liquid as water, ethanoland glycol which goes up in the ICPSA, this paper gets the motion figure of the up time t ofthe bubbles which changes with the inclined angle ,volume of the bubbles Vg, diameters ofthe pipe. This paper confirms the uncertain parameters,by calculating, and gets thecritical inclined angle's equation which could avoid the bubbles resistances. By comparing with formers' half-experience curves and using different liquids for theexperiments the outcome confirms and modifys this study theoretically andexperimentally.It is not only proved the theories, experimental studies and equations of thispaper are all right but also provided some calculation examples. This paper establishes thebasic theories for the bubbles motion in the ICPSA which could solve the issues aboutbubbles resistances in the natural circulation systems, especially about the development ofthe combination of the solar energy and the architecture. The study of this paper has greatmeaning and application values for engineering.