A major challenge for the aircraft industry is to improve engine efficiency and to reduce pollutant emissions for economic, technical and environmental reasons.
Aeronautical gas turbines have enjoyed a constant improvement for more than 60 years. This technology seems to have reached such efficiency levels that a technological breakthrough is necessary. Constant Volume Combustion (CVC) offers significant gain in consumption and could replace classical constant pressure combustion technologies, currently used in aeronautical engines. Mechanisms involved in isovolume combustion are not accurately controlled in the context of aeronautical chambers. Experimental, theoretical and numerical studies should provide a better understanding of CVC devices.
The objective of this thesis is to develop simulation tools to study the thermoreacteur concept. First, a zero-dimensional (0D) simulation tool is developed to describe the evolution of a CVC cycle. Models based on experimental correlations are used to build the 0D tool. Parameters have to be determined from numerical simulations.
Today, the 3D simulation of a CVC system is possible thanks to the recent progress of the LES (Large Eddy Simulation) methods developed at CERFACS. Simulations of the thermoreacteur concept have been carried out, and compared to experimental results obtained at the Pprime laboratory. Three operating points have been calculated.
The main conclusion is the existence of significant cyclic variations which are observed in the experiment and analyzed in the LES: the local flow velocity at spark timing and the level of residuals gases are the major factors leading to cyclic variations.
Constant Volume Combustion, Large Eddy Simulations, Turbulent Flames
Thierry POINSOT (CERFACS) : Advisor
Antoine DAUPTAIN (CERFACS) : Co advisor
Philippe GUIBERT (Université Pierre et Marie CURIE – Paris) : referee
Stephane JAY (IFP Energies Nouvelles – Rueil-Malmaison) : referee
Marc BELLENOUE (ENSMA – Poitiers) : member
Pascal BRUEL (Université de PAU) : member
Ludovic DAUDOIS (COMAT Aerospace – Flourens) : industrial member
Luc HERRERO (COMAT Aerospace – Flourens) : industrial member
Stephane RICHARD (TURBOMECA – Bordes) : industrial member