输气干线放空系统水力特性

高压输气干线放空管路内的介质属于非稳定流动,其水力计算不能采用一般站场管路适用的达西公式。为此,以Fano方程为基础,运用流体力学及输气管路流动基础理论进行程序编写,计算程序可实现对各时刻放空所对应的瞬时放空量、累计放空时间、截面压力及温度、储气量的求解。将程序计算结果与图解法计算结果进行对比,误差在2%以内,同时,程序计算法弥补了图解法仅能求得瞬时放空量而无法求得其他参数的缺陷。基于放空系统算例模型,对放空管路长度、管径、内壁粗糙度以及干线气体温度、压力等影响放空管路水力特性的主要因素进行分析,结果表明：放空管路长度和管径对放空系统影响较大,其他因素影响较小。以上研究可为输气干线放空管路系统设计提供参考依据。（图12,表2,参10）

Hydraulic characteristics of the blow-down system of gas trunk lines

Medium in the blow-down pipeline of high-pressure gas trunk lines is non-steady flow, its hydraulic calculation should not adopt Darcy formula which is applicable to normal pipelines of pump station. For this reason, based on Fano equation, a program has been made according to fluid mechanics and basic flow theory of gas pipeline, which can calculate blow-down volume, cumulative blow-down time, pressure and temperature of section and gas storage volume at any moment. Comparison of the program results and graphical result shows the error is less than 2%, besides, the program calculation method makes up the defect of graphical method that only instant blow-down volume can be calculated. Based on blow-down system calculation cases, major factors affecting hydraulic characteristics of blow-down pipeline, such as pipeline length, diameter, wall roughness and gas temperature, pressure have been analyzed. The results show that the length and diameter of blow-down pipe affect blow-down system stronger than other factors. The study can provide a reference to the design of blow-down pipeline of gas trunk lines.