Study Of Critical Characteristic Of Hump Air Resisitor In Submarine Water Supply Pipeline

In the submarine water supply project, submarine water supply pipe is valued with the rapid development of marine economy. Submarine pipeline which is constructed for water delivery plays a decisive role in solving the water supply problem, thus the design and safety operation of submarine pipeline need to be paid much attention. Because the exhaust valves cannot be applied, air exclusion in submarine pipeline is harder than that in pipeline on land. The hump air lock in submarine is an inevitable problem, which is very necessary to be researched.In this paper the relationship between the air lock and bubble motion is studied, and a summary on the bubble shape, motion equations, basic principle of coalescence and dissipation is made, the hump air lock is defined as the bubble which can cause stable resistance in the pipeline. The balancing characteristics of hump air lock are studied by both theory and experimental investigation. The balancing model is established and verified. The result shows that the relationship between the equilibrium angle and water flow velocity is parabolic. Air lock balancing ability will increase with bubble equatorial radius. Likewise, the theoretical model of resistance characteristics is verified by experiment. And the result shows that it can cause more resistance with the increasing polar area in water supply system.The principle is theoretically analyzed and critical data of air bubble dissipation has been gathered in the dissipation experiment. It turns out that the dissipation dip angle of bubbles will decrease with increase their volume, while dissipation flow velocity can remain the same. Hammer interaction model of the air lock and water flow is established and numerical simulation of water hammer with the characteristic method is made at last.