Approaches to Combustion Simulation

Abstract

Combustion processes (that is, conversion of chemical energy of propellant components into thermal energy of combustion products) are typical for various engineering systems. Working volumes wherein these processes can occur may be represented by combustion chambers of liquid-propellant rocket engines (LPRE), solid-propellant rocket engines (SPRE), air-breathing engines (ABE) steam-gas generators, magnetohydrodynamic generators (MHD generators), boiler furnaces of thermal electric power stations, and cylinders of internal combustion engines (ICEs) [1]. Besides, further conversion of combustion products with chemical conversions can proceed also in aircraft and rocket engine nozzles, ICE exhaust systems, LPRE gas ducts, etc.Working volumes of these propulsion and power generation systems feature the availability of a multiphase working medium, a wide range of temperature variation (from hundreds to some thousands of degrees) and pressure (from several tenths of MPa to tens of MPa), chemical conversions not only in gas phase but in condensed phase as well, changes of parameters of state of working medium against the background of intraphase and interphase heat-and-mass transfer and multidimensional flow of working medium, a high degree of turbulence, and nonuniformity of parameters over the working volume. The history of these processes defines, in the end, the energetic and ecological characteristics of a particular propulsion and power generation system. One of the ways of simulating the latter consists in the development of mathematical models of combustion processes along with subsequent computational experiments [2].Models of processes that occur in propulsion and power generation systems are usually based on mathematical models of some standard combustion modes for propellant components (oxidizer and fuel) in the working volumes. In the following paragraphs, some of these modes are considered in brief.Combustion in homogeneous zones (Figures 1.1, 1.2, and 1.3). This is the simplest mode of combustion that can be considered as a process of conversion of ideally mixed reactants (propellant components) into combustion products in a sample reactor. Working medium composition and state parameters are uniform at any two points of a reactor but can vary in time [3, 4]. Heat exchange (Qheat flow) of a reactor and an environment is also possible. Two patterns are most frequently used for simulation of combustion in homogeneous zones: 3 https://www.cambridge.org/core/terms.