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LES study of heat transfer in rocket engines with trans / subcritical injection transition.

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Required Education : Master ou Ecole d'ingénieur
Start date : 2 October 2017
Mission duration : 3 ans
Salary : Bourse CNES

The control of heat transfers in the combustion chambers of rocket engines remains an important issue for the lifetime of the solid walls of the chamber, in particular for engines operating with O2 and CH4 propellants. Moreover, at reduced thrust, the thermodynamical state of oxygen can change from transcritical at injection to subcritical in the chamber.

In continuation of the research undertaken by CERFACS on the development of Large Eddy Simulation methods for wall heat transfer with solid thermal coupling, this study aims to improve physical and numerical models in near-wall regions. In this framework, a detailed analysis will be carried out using low-Reynolds approaches, high-Reynolds approaches with wall law and hybrid approaches of the two-layers type. The development of the AVBP code will be validated by comparing computational results on various test cases representative of real conditions: a GOx / GCH4 multi-injectors case [1], and a LOx / GCH4 technology demonstrator chamber case.

During the thrust reduction phase, the change of oxygen at injection goes from transcritical to subcritical. This raises the important difficulty of modeling this transient physical phenomenon. New methods based on diffuse interfaces (second gradient method) and generalized thermodynamics have been developed [2]. These methods make it possible to treat continuously the primary atomization in subcritical regime on one hand, and the mixture of dense gas / light gas in transcritical regime on the other hand. The aim of the present study is to continue these methodological developments in collaboration with EM2C, and to validate them on elementary cases (mono-injector) and then on representative cases including wall transfers with and without coupling with the solid heat conduction.

This project is part of the long-term collaboration of CERFACS with CNES and ASL, which has notably allowed the development of codes for the computation of liquid rocket propulsion.

[1] CELANO , M., SILVESTRI , S., SCHLIEBEN , G., KIRCHBERGER , C. , KNAB , O. and HAIDN , O. Transregio SFB-TR40 Test Case 1. Single Element Combustion Chamber GCH4/GOX. Technical report

[2] Project ANR SUb&SUPER JET, coordinated by EM2C (Thomas Schmitt)



B. Cuenot – cuenot@cerfacs.fr

T. Schmitt – thomas.schmitt@ecp.fr