A computational fluid dynamics approach incorporating the Lagrangian framework is employed to model the impingement, mixing, and subsequent combustion in a liquid rocket engine with liquid oxygen and liquid methane propellants. Due to its high performance, non-toxicity and the fact that it might be manufactured on Mars, methane is being considered for a variety of future exploration missions by NASA and others. The objective of this investigation is to assess the capabilities of current state-of-the-art CFD methodology based on a Lagrangian framework to model the associated multi-phase, multi-component, reacting flow field of the “green” propellant mixture based propulsion system. The related formulations and corresponding CFD results of specific flow configuration are presented herewith. The difference in impingement and following spatial droplet distribution formulated using one-way and two-way coupling interaction modes are compared. The subsequent droplet evaporation and combustion processes are modeled using quasi-steady droplet evaporation and turbulent-mixing based standard Eddy Break-Up (EBU) combustion models with employed two-way coupling mode. The current analysis reflects that the Lagrangian approach is limited to model all major flow mechanisms concurrently as increase in surface area associated with the fundamental assumption of replacing liquid stream into a droplet series results in vaporization prior to impingement. However, by imposing an artificial heat transfer distribution, the droplet’s early evaporation can be delayed and the combustion of post-impinged droplets could be modeled.