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Numerical investigation of cavitating flow in variable area venturi on the basis of experimental data

Gümüşel, Hasan Tolg
Variable area cavitating Venturi is a throttling device that can regulate the flow rate used in liquid and hybrid rocket motors. It has a pintle mechanism which adjusts the flow area by moving back and forth in the direction parallel to the outflow from the Venturi. The flow rate is independent of the downstream pressure due to cavitation. This makes the variable area cavitating Venturi a very critical component for liquid propellant rocket engine because it can create an isolation between the inlet and the outlet in addition to controlling the mass flow rate. In this thesis, the cavitating flow through the variable area Venturi is investigated both experimentally and numerically. In order to solve the multi-phase flow, the open-source OpenFOAM software has been utilized. Schnerr-Sauer mass transport method is used to model the cavitation together with k-omega SST turbulence model. The model and the solver have tried to be verified and validated by experimental studies conducted on a simple version of the cavitating Venturi. The pintle positions, the upstream and downstream pressures, and the divergence angle of the Venturi has been examined in terms of their effect on the Venturi performance.