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Despite being used for decades, the complex phenomena occurring in Liquid Rocket Engine (LRE) combustion chambers are still to be completely understood. In fact, space propulsion is probably one of the most extreme applications of energy conversion by means of combustion, indeed all the components of a liquid rocket engine combustion chamber assembly have to withstand extreme temperatures and heat fluxes while operating at high pressure. These conditions are extremely challenging from the experimental standpoint, in fact state of the art experimental set-ups still do not provide extensive data for the investigation of the injectors near- field region of LRE combustion chambers. In this context, computational fluid dynamics (CFD) simulations are a key tool to provide the required data in order to develop predicting capabilities for the heat loads in the first part of the combustion chamber. In fact, CFD can provide a complete set of information which are hindered to experiments due to the extreme operating conditions of LRE. To this scope, numerical simulations need to include many phenomena occurring in the injectors near-field region which are, among others, turbulent mixing and combustion as well as flame - wall and flame - flame interactions. The objective of the present contribution is to investigate the injectors near-field region in LRE combustion chambers using both multi and single-injector combustor simulations. The baseline injection parameters and conditions are taken from a well known experiment of a single injector oxygen-methane combustor [4]. A recently developed dataset [1, 2] is used for the single- injector cases since it features a number of simulations in which the confinement length of the reference single injector is parametrically varied along with the boundary conditions of the lateral wall. Using the same reference injector geometry and parameters a 37-injector combustion chamber numerical configuration is developed, as shown in Figure 1 (see the attached pdf for both the figure and the caption). A detailed comparison between the single and multi - injectors configuration is carried out in terms of both the reacting flow- fields and the ensuing heat flux insisting on the walls in the injection region. All the simulations employed for the present study are consistently carried out by means of a validated unsteady Reynolds averaged Navier Stokes (uRANS) non-adiabatic flamelet based numerical framework recently developed by Indelicato et al. [3]. References [1] M. P. Celano, S. Silvestri, G. Schlieben, C. Kirchberger, O. J. Haidn, O. Knab, Injector characterization for a gaseous oxygen-methane single element combustion chamber, Progress in Propulsion Physics 8 (2016) 145-164. [2] A. Remiddi, G. Indelicato, P. E. Lapenna and F. Creta Thermal characterization in liquid rocket engines: a parametric analysis on injector arrangement AIAA Propulsion and Energy 2021 Forum, Paper number 2021 3567. [3] A. Remiddi, G. Indelicato, P. E. Lapenna and F. Creta \"Effects of injector lateral confinement on liquid rocket engines wall heat flux characterization: numerical investigation towards data-driven modeling\" AIAA Scitech 2021 Forum, Paper number 2021 0416. [4] G. Indelicato, P. E. Lapenna, A. Remiddi and F. Creta \"An efficient modeling framework for wall heat flux prediction in rocket combustion chambers using non adiabatic flamelets and wall functions\" International Journal of Heat and Mass Transfer 169 (2021) |
