NON-STEADY FLOW OF GASES IN PIPES

Here the problem of a correct prediction of transient pressures and pulsations in reciprocating compressors is considered, with a particular approach to connecting pipes. The possibility of employing the method of characteristics for gas flow is well known for ideal flows. I am using for real flows a numerical solution method which, in comparison with other mesh methods, decreases the mathematical errors of smearing because the influence of linear interpolations is much less than these mesh methods. I suggest dividing pipes in three sections: - the sections at the right and left ends have to be very short (only one cell) and mesh methods are used to apply the boundary conditions; - the intermediate section is the longest part (more cells) and uses a modified inverse method which makes linear interpolations to determine Dl, Db and DAA along characteristic lines. Linear interpolations are not used to determine l, b and AA at initial points of characteristic lines.