Numerical investigation of flame appearance and heat flux and in a deep-throttling variable thrust rocket engine

Much attention has been drawn to liquid-propellant rocket engine with thrust that can be varied on demand in recent years. A GO ₂ /kerosene deep-throttling variable thrust rocket engine using the newly proposed gas-liquid pintle injector is presented. Three-dimensional numerical simulations are conducted to investigate the flame appearance and heat flux distribution of the engine. The SST k-omega model is used for modeling turbulence and single-step finite-rate kinetics are used for modeling combustion. A grid sensitivity study is performed to examine the validity of the simulation results. The effects of total mass flow-rate, kerosene droplet injection velocity and kerosene droplet size distribution on flame appearance and heat flux distribution of the combustor are studied in detail. Three entirely different flame appearances are observed and it correspondingly causes different heat flux distributions. Details of the flow field structure and mass fraction contour inside the combustor are discussed to explore the cause of heat flux distribution. The work will provide a reference for the design of thermal protection system of the variable-thrust rocket engine operating with a wide range of space.