Three-dimensional simulation of cavitating flows in piping systems

The following research study refers to turbulent pipe flows, which are of great importance in hydraulic structures for hydro power schemes. This research study is aimed at the verification and the adaptation of a three-dimensional numerical program for general use in hydraulics. Computation fluid dynamics codes are seen as a future way of predicting hydraulic system performance, but codes capable of handling single phase and cavitating flow together are still under development. This program is based upon the differential equations by Navier-Stokes and works with the so-called k-epsilon turbulence model. The finite-volume method is used for discretisation of the flow field. The first step was the adaptation of the existing program for one-phase flow on the basis of hydraulic models. The second step is the extension of the program for cavitating flows, also by means of hydraulic models. After having adapted the numerical model for the one-phase flow the numerical results corresponded well with the results of the model tests. For cavitation studies we used results of the studies at the cavitation test stand. Proceeding from those results a numerical model was developed for the localisation of the cavitating zone. The described program is an efficient tool to avoid cavitation damages in water conduit systems.