Research On Dynamic Modeling And Simulation System Of Gas Pipe Network

With the transformation and upgrading of China’s industrial industry,fluid pipe network systems have generally existed in urban construction and industrial production.In this paper,the mathematical model of the fluid network is deeply studied,and the calculation model of the gas pipeline network is established based on the continuity equation,the momentum equation and the energy equation.The iterative calculation methods for steady-state and unsteady-state are deduced respectively.In addition,based on the flow field calculation and combined with the gas convection diffusion equation,the expression of gas mixture concentration is derived for the simulation calculation of the replacement process of gas pipe network.The simulation model of gas pipe network is composed of pressure nodes and various flow resistance elements.The calculation accuracy of pipe network is mainly affected by the resistance coefficient of these flow resistance elements.In the calculation of resistance coefficient,firstly,the flow resistance components contained in the gas pipe network are defined,classified and modeled.By consulting the practical fluid resistance manual,the resistance coefficients in various cases are coupled into the calculation program.For the resistance coefficient of tee pipe which is difficult to calculate,it is solved by two-dimensional linear interpolation and verified by simulation.In system architecture is a classic three-tier architecture of the Io T,and the communication technology of Lo Ra-MQTT is used for data transmission.The back-end algorithm of the computing software is written in C# language,and the front-end page is designed in WPF framework.According to the main requirements in production,several functional interfaces are designed.The continuously uploaded data from sensors is mapped into the virtual model,and the software gives feedback to the real pipe network through calculation.As a result,the Digital Twin is realized.Finally,the calculation software is applied to the actual industrial production,and the calculation results are compared with the measured data.The calculation results show that the on-line calculation function is very accurate for the calculation of pipe network flow field parameters,and the off-line simulation function is also close to the reality.For the steady state calculation of the software,the average relative error of pressure and temperature are 0.87% and 7.03%.For the calculation of unsteady replacement process,the average relative error of arrival time and completion time are 10.8% and 11.6%,which meets the accuracy requirements in engineering and has good application value.