The Research On Theoretical Analysis And Application Of Gas Pipework Calculation

To solve the problems in present hydraulic calculations of gas pipe networksuch as numerous data-inputting, unprecise output and a lack of hydraulic calculationmethods to keep consistent with steady flow and non-steady flow in real workingconditions of gas pipe network, in the paper the author has set up a mathematicalmodel of heat transfer process of gas in pipes on the basis of thermodynamic basictheories and obtained more accurate calculation methods of gas storage quantity inlong conveying pipes and urban pipe network of high pressure. This research achievement has been applied to real pipe network. Maincontents and results of the study are generalized as following:1. A computerized method of associated matrix A and loop matrix B in topologicalstructure of gas pipe network is fully analyzed, furthermore, the optimal combinationmethod of associated matrix A and loop matrix B is proposed. All these help to solvethe problem of numerous and fallible data inputting and the like efficiently.2. The calculation method of physical property parameter state equations of manyreal gases has been studied for its application in some typical substances. Thetheoretical results are compared with experimental data to reach a conclusion thatSHBWR equations can get higher precision in physical property calculations ofhydrocarbon compound and meet the needs of thermodynamic state calculations ofnatural gas of high pressure. The method in this paper has been applied in pipenetwork calculations of Beijing outer hoop. The results indicate that the calculatedprecision of characteristic number in pipe pressure drop has been increased by about10%.3. With graph theory and mathematical analysis used, a mathematical model ofsteady flow hydraulic calculation of gas pipe network is set up and the solution that aninterpolation method is used in the divergence problem of gas pipe networkcalculation is put forward. More open loop energy equations help to avoid virtualbalance phenomena in polygenetic gas pipe network of certain pressure. In calculation,performance curves of working pressure and flux in the compressor has beenconsidered. This approach has been put into practice in dispatching of Beijing coalgas pipe network4. On the basis of thermodynamic theory, variation of natural gas temperaturecaused by Joule-Tomson effect following the pressure drop in conveying pipelines hasbeen explored to find out an approximate calculation method of Joule-Tomsoncoefficient. Heat transfer between natural gas in pipes and soil has been fully analyzedwith derivation of concerning calculation models.5. A mathematical model of non-steady flow of natural gas is set up and solved withthe help of Flourier integral transformation and finite difference. The dynamicnon-steady flow calculation model of gas storage quantity which tallies with the gassupply load function has been found out and settled with analysis and numericalmethods respectively. The theoretical calculation results of Beijing outer hoop areconsistent with its real performance.