Study On Leakage Rule And Ventilation Scheme Of Natural Gas Pipeline In Yanying Mountain Tunnel

The length of Sino-Burma Oil&Gas Pipeline is more than2000km. There are60mountain tunnels built along with the pipeline, and55of them are oil and gas common pipeline tunnels. During the period of operation, there are many factors would cause gas pipeline leakage. Once the pipeline leakage happened in the tunnel, it may make an accident such as fire, explosion, even destroy the tunnel because the tunnel is airtight space. It is more difficult to repair the damaged gas pipeline in the tunnel than normal place. In addition, it would cause a lot of time and economical loss and impact the operation of the gas pipeline. Once the gas pipeline leaked in the tunnel, in order to reduce the accident risk, it is required that repair and maintenance should be operated under the scientific and efficient guidance. It is necessary to grasp the diffusion rule of natural gas leakage to make the repair scheme.This article uses the classical theory of fluid mechanics and method of CFD to study the typical tunnel of Sino-Burma Oil&Gas Pipeline, Yangyingshan tunnel. Analysis the leakage modes and reasons of the gas pipeline in Yanyingshan tunnel, find the relationship among the gas component, pipeline pressure, leaking size, leaking velocity and rate from the leakage source calculation. The time model of gas pipeline leakage in the tunnel is proposed after analyzing the simulation results by Fluent and the leakage source calculation results. Then, the model is verified and modified by simulating the different boundary conditions leakage. The new time model shows the relationship between the time of the tunnel be filled with natural gas and the leakage position, leakage pressure, pipe section area et al, and it can be used in other tunnels.According the arrangement of valve chamber on both ends of Yanyingshan tunnel, the total leakage in different leakage pressure and the duration of jet leakage are worked out by CFD. Furthermore, advises are proposed to improve the valve chamber layout.At last, the efficiency of different ventilation schemes after the gas pipeline leakage in Yanyingshan tunnel are calculated by CFD. the ventilation optimization scheme contains the best air supply way, the best horizontal position and height, the best layout spacing. The suggestions about the selection of fan type and tunnel portal design are proposed through the results.