6. Overall pump performance

6.1 Qualitative evolution of pump performance under two-phase conditions

Whatever the type of pump, it can be observed that, for a fixed operating point (which depends on the circuit in which the pump is flowing), its performance decreases as the initial gas rate increases. The degree to which performance drops depends on a number of geometric, thermodynamic and kinematic factors.

The changes in performance observed experimentally lie on a characteristic curve that obeys a quadratic evolution of pressure differences with flow rate, as shown, by way of example, by the experimental results presented in figure