Etude de l'ecoulement cavitationnel dans un injecteur diesel simple trou.

摘要

The objective of this study is to determine the effects of the properties of the diesel as well as the injection conditions on the internal flow of a single-hole injector. To achieve this, a reliable numerical model has been developed and simulations have been performed on a single-hole diesel injector under cavitating conditions. Cavitation has been calculated using an Eulerian single-fluid model based on the Rayleigh-Plesset equation for bubble growth. The model has been validated by calculating several coefficients which are: the discharge, the area-contraction and the velocity coefficients. These coefficients have been determined under different Reynolds and cavitation numbers to determine the impact of each dimensionless number on the flow. Both the Reynolds and the cavitation numbers have an effect on the flow. The augmentation of the Reynolds number tends to increase the discharge coefficient by reducing the cavitation. However, decreasing the cavitation number leads to more cavitation, hence to a reduced discharge coefficient. It has also been determined that simulation at high pressures can be reproduced with a lower injection pressure as long as the Reynolds and cavitation numbers stay the same. This amounts to affirm that the only dimensionless numbers that govern the flow are the Reynolds and the cavitation numbers. Ultimately, a reliable numerical model has been set up for future studies.