面向对象法燃气管网水力计算

Hydraulic Calculation of Gas Pipeline Network Based on Object-oriented Method

城镇燃气管网在不断扩大与改建,多源、多环、多级和多变是其典型特点,目前常用传统算法工作量很大,一旦管网结构或运行工况发生变化,需要重新编号形成新的矩阵方程求解。基于“面向对象”的思想,使用Visual Basic软件编制了燃气管网水力计算程序,结合算例在软件操作和数据结果方面与传统算法(节点法、环差法)进行了对比。软件操作方面,管网结构改变时,面向对象法直接增删相应元件或修改个别元件属性即可直接计算。节点法和环差法则需要重新编号,还要重输元件属性,再生成新的系数矩阵后求解方程组。环差法需按连续性方程重新分配流量初值,而且每次管网结构改变时传统算法都要重复以上步骤,故面向对象法操作更加简便快速。数据结果方面,3种算法在3种工况(原始工况、添加元件工况、删除元件工况)下的环闭合差都满足要求,且面向对象法最小。在节点压力的计算结果上,面向对象法与节点法偏差更小,而管段流量结果面向对象法与环差法偏差更小。根据计算原理,在迭代过程中,节点法更新的是节点压力,故得到的压力较精确,环差法则是计算校正流量更新流量,其流量较精确,所以面向对象法的节点压力、管段流量计算结果都更贴近较精确的值。

The urban gas pipeline network is expanding and reconstructing,and its typical characteristics are multi-source,multi-ring,multi-level and changeable.At present,the traditional algorithm has a lot of workload.Once the pipeline network structure or operating conditions change,it needs to be renumbered to form a new matrix equation.Based on the"object-oriented"idea,by using Visual Basic software,the hydraulic calculation program of gas pipe network is compiled,and the software operation and data results are compared with the traditional algorithms(node method,ring difference method)in combination with examples.In terms of software operation,when the pipeline network structure changes,the object-oriented method can directly calculate by adding or deleting the corresponding components or modifying the attributes of individual components.The node method and ring difference method need to be renumbered,and the component attributes should be re-inputted to form a new coefficient matrix to solve the equations.The ring difference method needs to redistribute the initial value of flow according to the continuity equation,and the traditional algorithm should repeat the above steps every time the pipe network structure changes,so the object-oriented method is more simple and fast.In terms of data results,the loop closure errors of the three algorithms under three working conditions(original condition,adding component condition and deleting component condition)all meet the requirements,and the object-oriented method is the smallest.In the calculation results of node pressure,the deviation between object-oriented method and node method is smaller,while the deviation between object-oriented method and ring difference method is smaller in pipeline flow rate results.According to the calculation principle,in the iteration process,the node method updates the node pressure,so the obtained pressure is more accurate.The ring difference method is to calculate correct and update the flow rate,and its flow rate is more accurate.Therefore,the calculation results of the node pressure and pipeline flow rate of the object-oriented method are closer to the more accurate values.