Research On Current Rush To Interception Air-Mass With Delivery Pipeline System And Water Hammer With Gas

Research on current rush to interception air-mass in delivery pipeline system and water hammer with gas is a branch of concurrent gas-liquid flow. For it refers to many fields, such as fluid mechanics, transient flow, concurrent gas-liquid flow and thermodynamics, the problem is very complicate, and there are still some issues to be deeply studied actually.Combining physical experiments and theoretical analysis, this literature has performed thorough research on gas properties of delivery pipeline system, pressure current rush to interception air-mass in pressure pipeline, water hammer with gas that happens with gas releasing and liquid column separating. Some new ideas and main content showed in the article are as the follows. 1st. Research on gas properties in pipeline systemAccording to document references, by far there is no systematic research on gas thermal insulation coefficient in delivery pipeline with gas. Gas thermal insulation coefficient under different transient flow in pressure pipeline system has been studied through physical experiments and theoretical analysis on thermodynamics. The physical experiments and theories on thermodynamics prove that gas thermal insulation coefficient changes apparently when hydraulic transition process happens. So four appropriate processes weregiven-sub-process 1 of compressing, sub-process 2 of inflating, sub-process 3of inflating, sub-process 4 of compressing. In the sub-process 2 of inflating and sub-process 4 of compressing, gas thermal insulation coefficient was 1.4-1.6; whereas it was 1.15 in the other two processes.2nd. Research on pressure current rush to interception air-mass in pipelineBased on the study of gas properties in pipeline system, the research whichwas performed through physical experiments and mathematical modelingcalculation, current rush to interception air-mass contents in different pipeline, theinfluences of different stop gate closing-velocities to pressure current rush tointerception air-mass in pipeline and some other factors, were given much consideration on the influence of current rush to interception air-mass in pressure pipeline. The physical experiments and theoretical analysis indicate that rush pressure caused by current rush to interception air-mass in delivery pipeline system has much to do with the content of air-mass. The maximum rush pressure occurs not under the condition -much lower or much higher content of air-mass, but when the initiate volume of interception air-mass makes up 1~2% of total pipeline volume, maximum current rush to interception air-mass pressure happens. Numerical calculation has been given in the research, and it turned out that experimental results tally with theoretical calculation results after comparison. Meanwhile, deeply research has been done on the analytic root of current rush to interception air-mass with delivery system.3rd. Research on water hammer with gas in pressure conduit system Through physical experiments, researches on pressure conduit system with gas releasing and liquid column separating, which consist of observing flow patterns, testing the conditions under which liquid column separation brings into existence and the water hammer in water interception collision, and studying effects resulting from gas content and different water velocities in pipeline, was done. Based on physical experiments, establishing mathematical model, carrying on theoretical calculations, and contrasting experimental results with theoretical ones, it turned out that under the same initiate flow rate, the quicker the closing of the ball valve, the longer the stable time when the liquid gets to vaporizing pressure, and the bigger the water hammer in water interception collision; under the same closing velocities of the ball valve, the larger the initiate flow rate, the longer the stable time when the liquid gets to vaporizing preesure, and the bigger the water hammer in water interception collision. To one pipeline, under the same length of upper reaches of t...