Abstract

For reduction of pressure oscillations during transient processes in pipelines, air chambers built in downstream of the pump are often used. The movement of the liquid level in the air chamber can only be traced by solving the mathematical model made for the particular elastic system. Since in this case a model of distributed parameter system may be used, this leads to a quasi linear hyperbolic boundary value problem. To solve this only numerical methods can be suggested for which, however, special computer programs are needed. On the basis of the mathematical model it is expedient to look for such invariants which are characteristic for the dimensionless system. With the adequate choice of the set of values of the invariants the solutions of cases expected in the design practice can be Produced, lf the number of invariants wefe large their bandling would again make the Procedure complicated. Therefore it is advisable to strive after production of possibly fewest, i.e, optimally chosen invariants. One method of achieving this is simplification of the model to such an extent which is still allowable.