The Study Of Analysis The Cut-out Cavity And Gas-water Two-phase Flow And Impact On Hydraulic Transition Process

In order to meet the requirement of China’s rapid economic development and to solve thecontradictions of uneven distribution of water resources, many new long-distance water supply projects hasbeen set up in China in recent years, the long distance water supply pipeline projects is always ups anddowns, high lift, large quantity of flow, and its layout is complex. Water supply pipeline hydraulictransition process contains all the water hydraulic transition process which include pumping stations andgravity flow pipe water, The definition of water supply pipeline hydraulic transition process is processhappened unsteady flow pattern that transition from one steady state to another steady state status.Although the duration of water hydraulic transition phenomenon is very short, it can cause seriousengineering accidents, especially in water hammer of cavities collapsing, the damage caused by waterhydraulic transition phenomenon is diverse, When the water hydraulic transition phenomenon appears notonly can cause damage to the pumping equipment and water supply pipeline system, but also can lead tothe operator casualties and interruption of water supply, which seriously affecting industrial, agriculturaldevelopment and people’s normal life. It is necessary to study of water hydraulic transition process, andwhen the water hydraulic transient changes that must be accompanied by the pipeline pressure shocks andgas-water two-phase flow pattern changes.This paper expoudd the causes of cut-out cavity gas-water two-phase flow pattern which includingsource of gas and conditions of gas preserve in the pipeline gas-water two-phase flow pattern, the cut-outcavity gas-water two-phase flow classification, The process that gas-water two-phase flow pattern in thehydraulic transition process transforms into another. In addition, on the basis of analysis of the cut-outcavity gas-water two-phase flow theory, this paper research the impact on the hydraulics principle ofhydraulic transition process when take measure of exhaust and injection gas and single water injection towater supply pipeline. And on the study of relevant theory, this paper expound the method of build ofhydraulic transition process mathematical calculations model and deduce the boundary conditions equationof the exhaust and injection gas, estabilished corresponding mathematical calculation model of cut-outcavity gas-water two-phase flow and when injection-exhaust gas and one-way water injection. Analysischange the closing valve time of gravity flow water supply pipeline and quantity of flow and closing valvetime of the gas-water two-phase flow pattern pipeline and hydraulic transition process, and research the gas-water two-phase flow pattern and hydraulic transition process of gravity flow and pressure flow watersupply pipeline when take measure of injection-exhaust gas and one-way water injection. Provide areference for similar hydraulic transition process optimization.