Gas networks simulation

Simulation allows to predict the behaviour of gas network systems under different conditions.

Such predictions can be effectively used to guide decisions regarding the design and operation of the real system.

Depending on the gas flow characteristics in the system there are two states that can be matter of simulation: In the gas networks simulation and analysis, matrices turned out to be the natural way of expressing the problem.

This may consist in supplying domestic or commercial consumers, filling gas storage holders, or even accounting for leakage in the network.

These requirements are met by the graph theory which permits representation of the network structure by means of the incidence properties of the network components and, in consequence, makes such a representation explicit.

The calculation of the pressure drop along the individual pipes of a gas network requires use of the flow equations.

Instead, each formula is applicable to a limited range of flow and pipe surface conditions.

The networks equations are nonlinear and are generally solved by some of Newton iteration; rather than use the full set of variables it is possible to eliminate some of them.

The method is based on the set of the nodal equations which are simply mathematical representation of Kirchhoff's first law which states that the inlet and outlet flow at each node should be equal.

Basically the fundamental set of loops can be found by constructing spanning tree for the network.

The standard methods for producing spanning tree is based on a breadth-first search or on a depth-first search which are not so efficient for large networks, because the computing time of these methods is proportional to n2, where n is the number of pipes in the network.

The importance of the mathematical methods' efficiency arises from the large scale of simulated network.