输气管道完全堵塞对压力与流量影响的数值模拟

The numerical simulation on the influence of complete blockage on pressure and flow rate in gas pipelines

输气管道因压力或温度骤变、脱水不达标、清管不及时等因素很可能造成管道完全堵塞,严重影响其正常运行与平稳供气。针对管道堵塞定位问题,现有方法尚处在理论分析与实验阶段,还无法满足现场实际需求。以某输气管道为例,采用SPS仿真软件,模拟分析输气管道堵塞对沿线特别是近端点500 m处的压力与流量的影响,验证现有压力或差压变送器对瞬变参数监测的可行性。结果表明:当输气管道起点与终点压力保持恒定时,一旦某处发生完全堵塞,该处上游的压力因气体压缩而迅速升高,反之,下游的压力因气体膨胀而迅速降低;突变压力波将分别在堵塞点上、下游管段内来回传播,波峰将逐渐衰减,直至两管段沿线各点压力分别达到起、终点压力时,两管段内无气体流动;距堵塞点越近,压力与流量波动越明显,且达到稳态的时间越短。研究结果为基于压力与流量监测的输气管道堵塞定位方法的深入研究奠定了理论基础。

Because of the pressure or temperature sudden change, substandard dehydration and untimely pigging and other factors, a gas pipeline is likely to be blocked completely, and consequently its normal operation and smooth gas supply is impacted seriously. The existing blockage locating methods are still in the stage of theoretical analysis and experimental study, and cannot meet the actual needs of the site. In this paper, a certain gas pipeline was taken as an example. The effects of complete blockage on the pressures and flow rate along the gas pipeline, especially 500 m away from both ends, were simulated and analyzed by the simulation software SPS. And the feasibility of the existing pressure or differential pressure transmitters on transient parameters monitoring was verified. It is shown that when the pressures at both ends of the gas pipeline are constant, the pressure in the upstream of the complete blockage increases rapidly due to gas compression while that in the downstream decreases rapidly due to gas expansion. And the pressure waves propagate back and forth along upstream and downstream pipeline sections and the wave crest attenuates gradually. There are no gas flows through the two pipeline sections when the pressure along the both pipeline sections is equal to that at the initial point or the terminal point respectively. The closer it is to the blockage, the more obvious the pressure and flow fluctuation are and the shorter time it takes to reach a steady state. The research results lay a theoretical foundation for the further study of gas pipeline blockage location method based on pressure and flow monitoring. （9 Figures, 1 Table, 20 References）