Bipropellant combustion in a liquid rocket combustion chamber

Abstract

A comprehensive computer simulation code is developed for the combustion-flow analysis of a bipropellant liquid rocket engine combustor. A bipropellant group combustion model is built in the computer code to facilitate the determination of various combustion modes, including the combustion of oxidizer droplets, fuel droplets and gas mixture. Several physical submodels are also adopted to account for the interaction between bipropellant droplets and the gas-phase flow. An axisymmetric cylindrical liquid rocket engine combustion chamber installed with two annular-ring injectors is selected to demonstrate the capabilities of the present computer simulation code. Two types of injection processes are analyzed. One is characterized by a non-premixed spray process and the other is a premixed spray process. Selected numerical computations show that the premixed spray results in a better utilization of combustion chamber space and gives a higher combustion efficiency in general. But finer-droplet sprays do not necessarily lead to a higher combustion efficiency as traditionally speculated. Nomenclature A = Arrhenius law constant B = transfer number C D = drag coefficient C f = correction factor for the droplet vaporization due to the convective effect C p = specific heat at constant pressure C s = stoichiometric fuel/oxidizer ratio D = energy dissipation due to drag force D k = turbulent kinetic energy shared by droplets E = activation energy F = aerodynamic drag force G = viscous tensor stress G c = spray group combustion number H = heat transfer between gas and droplet phases h = total enthalpy, fC p dT + q°Y f /w f K = turbulent kinetic energy L = latent heat m = droplet evaporation/combustion rate N t -mean droplet number density n = droplet number density n = droplet number density decaying sink caused by droplet evaporation/combustion P -pressure q° = heat of combustion R = universal gas constant R f = fuel consumption rate R 0 = characteristic length r f = volume-mean droplet size T = temperature u = velocity in x direction V = velocity vector v = velocity in r direction w = molecular weight Y = species concentration as mass fraction e = turbulent dissipation rate 0 = droplet void-deducted volume ratio A = heat conductivity

Modeling and simulation of a two combustion chambers liquid propellant engine

“…a pump or a controller, or a phenomenon such as combustion instability. For example, general relations for simulations of the combustion chambers are given by Liang and Mason (1986), Habiballah et al (1991), Jiang and Chiu (1992), Wang (1993), Khosravi and Mazaheri (2000) and Ivancic and Mayer (2002). Analysis of LPRE turbomachinery is covered by McDaniel and Snellgrove (1992) and Chen (1995).…”

Application of a simulation algorithm to a specific liquid propellant engine with experimental verification

“…Static models for all engine components are presented by Tishin and Gurova (1989). Simulation of combustion chamber related studies are pursued by Habiballah et al (1991), Ivancic and Mayer (2002), Jiang and Chiu (1992), Osherov et al (1996) and Wang (1993). There are also literature on analysis of LPE turbo-machinery (McDaniel and Snellgrove, 1992;Chen et al, 1995).…”