Large eddy simulations of high pressure rocket propellant #3 aviation kerosene spay in pressurized quiescent environments

In a diesel-like condition, kerosene behaves differently from that in the aircraft engine. In order to understand the process, large eddy simulations are conducted to predict the high injection pressure kerosene spray at the ambient pressure ranging from 2.0 to 5.6 MPa with Eulerian-Lagrangian method. Three kinds of sub-grid models, like KEqn, dynamicKEqn and Smagorinsky, are validated with experimental data. It is found that KEqn model could produce the good predictions, dynamic KEqn model always underestimates the spray penetration while Smagorinsky model overestimates the spray penetration at the ambient pressure of 2.0 and 3.0 MPa and underestimates the spray penetration at the ambient pressure of 4.0 and 5.6 MPa. Around the nozzle exit, where the exchange of kinetic energy from the parcels to the gas occurs intensively, the maximum parcel diameter drops sharply by 73~74% as the ambient pressure reaches 5.6 MPa. It is found that as the ambient pressure rises, the parcel velocity drops more sharply. At the ambient pressure of 2.0 and 3.0MPa, the zone which contains only low velocity parcel (≤50m/s) firstly appear around 0.0045 m long Z axis, while the zone appear firstly around 0.0032 and 0.003 m at the pressure of 4.0 and 5.6MPa respectively. It is also unveiled that the pressure ratio (pinj/pamb) of 17.9, 22.5, 26.7, 35 has no obvious influence on the total parcel surface which increase almost linearly along with time while it affects the average parcel surface obviously. Finally it is found that the pressure ratio may affect the Sauter Mean Diameter during the early time, then it becomes relatively steady, around 7e-6 m.Abbreviations: AMR, Adaptive Mesh Refinement; ARL, Army Research Laboratory; JP-8, Jet Propellant #8 aviation kerosene; LES, Large Eddy Simulation; NATO, North Atlantic Treaty Organization; pamb, ambient pressure; pinj, injection pressure; RANS, Reynolds Average Navier-Stokes; RP-3, Rocket Propellant #3 aviation kerosene; SFC, single fuel concept; SMD, Sauter Mean Diameter; SOI, Start of Injection