Effects of LOX Particle Diameter on Combustion Characteristics of a Gas-Liquid Pintle Rocket Engine

Abstract

LOX/GCH4 pintle injector is suitable for variable-thrust liquid rocket engines. In order to provide a reference for the later design and experiments, three-dimensional numerical simulations with the Euler-Lagrange method were performed to study the effect of the initial particle diameter on the combustion characteristics of a LOX/GCH4 pintle rocket engine. Numerical results show that, as the momentum ratio between the radial LOX jet and the axial gas jet is 0.033, the angle between the LOX particle trace and the combustor axial is very small. Due to the large recirculation zones, premixed combustion mainly occurs in the injector wake region. As the initial LOX particle diameter increases, the LOX evaporation rate and the combustion efficiency decrease until the combustion terminates with the initial LOX particle diameter greater than 110 μm. The oscillation amplitude of the combustor pressure increases significantly along with the increase of the initial LOX particle diameter, and the low-frequency unstable combustion occurs when the initial LOX particle diameter exceeds 60 μm. The combustor pressure oscillation at about 40 Hz couples with the swinging process of spray and flame, while the unsteady LOX evaporation amplifies the combustor pressure oscillations at 80 Hz and its harmonic frequency.

Effect of Local Momentum Ratio on Spray Windward Distribution of a Gas–Liquid Pintle Injector Element

“…Therefore, the pintle engine has a uniform combustion flow field, which differs from conventional engines with dense injector units on the injection faceplate. Previous studies [10][11][12] suggest that the spray angle of gas-liquid pintle injectors always remain unchanged, which contributes to stable recirculation flow patterns and the mixing ratio distribution inside the combustor. The flame structure, combustion efficiency and stability of the pintle engine are all highly dependent on the spray characteristics.…”

Numerical Study on Combustion and Atomization Characteristics of Coaxial Injectors for LOX/Methane Engine

“…As a propellant for rocket engine, methane has many advantages such as low carbon deposition, low cost, high specific impulse, and environmental protection [4][5][6][7]. Because of the importance in liquid rocket engine, many experimental and numerical researches have been done on injectors in recent years [8][9][10]. The shear coaxial injector combines simple structure with high reliability, while the swirl coaxial injector has better droplet mixing and atomization ability, and they are suitable for gas-liquid injector and liquid-liquid injector in rocket engine [2,11].…”