Flow modelling in gas transmission networks. Part I – Mathematical model

The mathematical problem, corresponding to the physical problem of the gas flow in transmission networks, is formulated in the first part. The nonstationary flow of viscous, compressible gas is modelled. All elements of the transmission networks which influence the flow, functions describing delivery and consumption of gas and control of the network are taken into account. The method of solution and algorithms are presented in the second part of the paper.