地下综合管廊天然气管道泄漏扩散模拟研究

为了研究管道异常泄漏时天然气的扩散情况，采用Fluent软件模拟研究不同压力条件下气体在管舱内的浓度分布特性，核算保护半径为7.5 m时的报警探测器在灾变时的响应时间，以达到指导报警探测器设计的目的。结果表明:当泄漏压力为103.3 kPa，200.0 kPa时，对应的报警响应时间分别为2.15 s，0.45 s，报警响应时间随着泄漏压力的增大而减小，在常规中压输出压力下，响应时间最大值为2.15 s；同一泄漏压力下，管舱内气体扩散距离与泄漏持续时间成正相关；报警探测器的响应浓度以爆炸下限的20%为推荐值。

Study on simulation of leakage and diffusion for natural gas pipeline in underground utility tunnel

To study the diffusion of natural gas during the abnormal leakage of pipeline, the distribution characteristics of gas concentration in the pipe compartment under different pressures were simulated by using the Fluent software. The response time of the alarm detector with the protection radius of 7.5 m in the accident was calculated so as to guide the design of alarm detector. The results showed that when the leakage pressure was 103.3 KPa and 200.0 KPa, the corresponding alarm response time was 2.15 s and 0.45 s respectively, the alarm response time decreased with the increase of leakage pressure, and the maximum response time was 2.15 s under the conventional medium output pressure. Under the same leakage pressure, the diffusion distance of nature gas in the pipe compartment presented a positive correlation with the duration time of leakage. The response concentration of alarm detector was recommended to be 20% of the lower explosive limit.