8 TH EUROPEAN CONFERENCE FOR AERONAUTICS AND SPACE SCIENCES (EUCASS) Copyright (R) 2019 by CIRA s.c.p.a.. Published by the EUCASS association with permission. CFD KINETIC SCHEME VALIDATION FOR LIQUID ROCKET ENGINE FUELLED BY OXYGEN/METHANE Pasquale Natale*, Guido Saccone** and Francesco Battista*** * Centro Italiano Ricerche Aerospaziali Via Maiorise, 81043 Capua (CE), Italy, p.natale@cira.it **Centro Italiano Ricerche Aerospaziali Via Maiorise, 81043 Capua (CE), Italy,g.saccone@cira.it ***Centro Italiano Ricerche Aerospaziali Via Maiorise, 81043 Capua (CE), Italy,f.battista@cira.it Abstract In recent years, greater attention has been paid to green propellants, among those liquid methane is one of the most promising choice. This has also been encouraged by the abolition of hydrazine for its intrinsic human-rating concerns. On the other hand, the adoption of methane as a fuel introduces some issues about modelling. Detailed kinetic schemes are required to properly reconstruct combustion process. This is especially true for rocket propulsion problems, in which the combustion is characterized by high pressure and not stoichiometric mixture ratio. Moreover, detailed scheme may not be feasible for CFD applications, due to high computational cost. For this reason, adoption of reduced schemes is encouraged, even if detailed mechanism description is required. In the present work, a reduced kinetic scheme (HPRB, by CIRA) will be presented for a specific LRE application. Some experimental firing-tests (i.e. FSBB test-campaign) will then be compared with model results, in order to validate the proposed model. 1. Introduction Traditionally, high performance rocket engines have used LOX and hydrogen or LOX and kerosene, while, as such, methane has not yet been used in a commercial launch vehicle. Nevertheless, several LOX/methane engines have been built and or under development. Methane exhibits peculiar thermodynamic properties in typical operative range: it has a high specific heat, useful for cooling purposes; it has a high critical temperature, which leads to higher storage temperature (thus, lighter thermal insulation systems); it has a relatively high density, which allows the use of smaller tanks (thus, lighter structures). Hereinafter, a short, not exhaustive, list of projects in which methane has been selected as fuel:  MIRA (Avio KBKhA Khrunichev Progres Kuznetsov) cryogenic LOX/liquid methane upperstage replacing both Zefiro 9 and AVUM.  XCOR along with Alliant Techsystems Inc. (ARK) built a 33kN LOX/methane regenerative cooled engine as part of NASA’s Exploration Technology Development Program (XR5M15 in Figure 1).  A Purdue University student team has designed, built, and tested a liquid LOX/Methane thrust chamber as part of NASA’s Project Morpheus. In this case, the thrust chamber has the ability to “throttle”. It is designed and tested for automated landing systems.  Aerojet developed a LOX/Methane reaction engine based on their previous LOX/Ethanol engines, and a 24.5 kN main engine for lunar lander assents (Figure 2).  RAPTOR is a staged combustion, methane-fuelled rocket engine under development by SpaceX. The engines are powered by cryogenic liquid methane and liquid oxygen (LOX), rather than the RP-1 kerosene and LOX used in all previous SpaceX Falcon rockets which use or used Merlin 1A, 1C, & 1D and Kestrel engines. The Raptor DOI: 10.13009/EUCASS2019-680