PhD defense - M. Sanjosé

of combustion chamber operated with liquid fuel

Delivered by INP Toulouse
Speciality: Fluid dynamics

December 14, 2009 - CERFACS

Aeronautical gas turbines are facing growing demands on emission reductions. Indeed, the quality of the air-fuel mixture directly triggers the formation of pollutants degrading the environment. Large Eddy Simulation is an accurate numerical method to predict turbulent mixing in combustors. Adding the liquid phase of the fuel in these simulations also becomes necessary to properly predict the injection process and the vaporization of the fuel in the combustion chamber.

The purpose of this dissertation is to evaluate the accuracy and reliability of Euler-Euler LES in a complex combustor configuration. The injection and vaporization processes of the fuel liquid phase are both modeled in the present LES as they drive the formation of the fuel gas phase. Moreover, the numerical methods that solve the continuous equations of the disperse phase must be accurate and robust in realistic combustor configurations.

The simulations shown in the present study reproduce the non-reactive two-phase flow of the ONERA Mercato test bench. The experimental set-up is equipped with an air-swirler injection system typical of actual turboengine combustors. Comparisons between experimental and LES results help validating the Euler-Euler approach, and the injection and vaporization models. The unsteady flow simulations also provide detailed information on the dispersion and mixing processes in the Mercato set-up. The accuracy of the Euler-Euler method on this configuration is also compared with that of the Euler-Lagrange method more often used for this type of two-phase flow. The statistics of several Euler-Euler simulations are also compared with the experimental ones to assess the influence of the various numerical strategies used to solve the equations for the disperse phase.