Numerical simulation of the unsteady combustion of solid rocket propellants at a harmonic pressure change

This study focuses on a numerical investigation of the unsteady burning rate o

A mathematical model of metallized solid propellant combustion under the changing pressure

This paper presents the mathematical model describing a non-stationary combustion of metallized solid propellant. The model takes into account the heat transfer, the oxidizer decomposition and gasification of the solid propellant, two-phase, dual-velocity, two-temperature reactant flow over the propellant surface. The conditions on the surface perform the conservation of energy and mass fluxes. The model is based on the research works [1, 2]. Our research provides data of the non-stationary burning rate depending on the Al powder dispersion and the pressure drop value

Mathematical modelling of sparkplug ignition of a coal-dust monodisperse suspension in a methane-air mixture

The paper provides the numerical simulation of a coal-dust monodisperse suspension sparkplug ignition in a methane-air mixture. The methane-air mixture is not stoichiometric. The aim of the research is a design-theoretical determination of the minimum ignition energy of coal-dust-methane-air mixture (CDMAM) depending on the methane volume fraction. Simulation has shown that the increase of the methane volume fraction leads to the decrease of the CDMAM minimum ignition energy, and with the expansion of coal particles the minimum ignition energy rises

Investigation of the combustion stability of methane-air mixture in recuperative burners of different geometries

The results of numerical investigations of 5.5% methane-air combustion stability in heat recuperative burners (counter flow burner, U-shape burner and Swiss-roll burner) are presented in this paper. The investigation is carried out with the use of commercial CFD package Ansys-Fluent. The boundaries of combustion stability of 5.5% methane-air mixture depending on the gas flow rate at the inlet of the burners are determined

Thermal interaction of biological tissue with nanoparticles heated by laser radiation

We explore the problem of thermal interaction of nanoparticles heated by laser radiation with a biological tissue after particle flow entering the cell. The solution of the model equations is obtained numerically under the following assumptions: a single particle is located in a neighborhood exceeding the particle size; the environment surrounding the particle is water with the conventional thermal characteristics. The model equations are deduced from the particle and the environment energy conditions taking into account the heat transfer in the particle and in its environment by conduction. We also assume that at the boundary between the particle and the surrounding water the perfect thermal contact takes place

Numerical investigation on burning stability of the coal-dust methane-air mixture in a recuperative burner

The paper is devoted to numerical investigation on combustion singularities of the bi-dispersed coal-dust methane-air mixture in a slot recuperative burner. The aim of the research is to determine the stable combustion conditions of the methane-air mixture depending on the fuel flow rate at the inlet of the burner and on the parameters of the mixture (the particle size and the mass concentration of the coal particles, the percentage composition of inert particles and the methane volume content). The problem was solved by finite difference method. The regimes of stable combustion for the coal-dust methane-air mixture depending on the fuel content and the fuel flow rate at the inlet of the burner the have been defined

A mathematical model of metallized solid propellant combustion under the changing pressure

This paper presents the mathematical model describing a non-stationary combustion of metallized solid propellant. The model takes into account the heat transfer, the oxidizer decomposition and gasification of the solid propellant, two-phase, dual-velocity, two-temperature reactant flow over the propellant surface. The conditions on the surface perform the conservation of energy and mass fluxes. The model is based on the research works [1, 2]. Our research provides data of the non-stationary burning rate depending on the Al powder dispersion and the pressure drop value

Mathematical modelling on extinction of metallized composite solid propellant under a sudden drop in pressure

This paper presents a physico-mathematical combustion model of the metallized composite solid propellant (MCSP), which takes into account the chemical reactions in the condensed and gas phases. The model describes convection and diffusion of the propellant components in the two-phase flow over the fuel surface and combustion of the aluminium particles emitted from the fuel. The constructed model provides the opportunity to calculate the fuel combustion rate under the constant and variable pressure. The obtained calculation results of the MCSP combustion rate using the model are in good agreement with the known experimental data. The manuscript also provides data on the modelling of the MCSP extinction under the sudden pressure change. According to the conducted numerical simulations, the value of the pressure drop, leading to the fuel extinction, depends on the mass fraction of the aluminium powder in the fuel composition and its dispersion. With an increase in the mass fraction of the aluminium powder and/or a decrease in the size of the aluminium particles emitting from the fuel surface, the extinction process occurs at a greater value and under a higher rate of the pressure drop. The numerical simulation has also shown that the addition of the aluminium powder to the composition of the propellant increases the combustion stability under the sudden drop in pressure over the combustion surface

Combustion of aluminum powder-air suspension in a swirl flow

The article is devoted to the numerical solution of the problem of the combustion of powder metal fuel in a combustion chamber with swirling flow. A physico-mathematical model of the flow of an air suspension of aluminum powder in a swirling flow in a cylindrical combustion chamber with a sudden expansion is presented. The physical and mathematical formulation of the problem is based on the approaches of the mechanics of two-phase reacting media. The solution was carried out using the arbitrary discontinuity decay method. The results of a numerical parametric study of the features of the combustion of an air suspension of aluminum powder depending on its composition, the axial flow rate of the mixture at the entrance to the combustion chamber, and the value of the swirl speed are show

Study of critical conditions of spark ignition and burning rate of a boron powder suspension in a propane–air mixture

A physical and mathematical model of spark ignition and combustion of boron powder suspension in a propane-air mixture is presented. Dependences of the critical energy of spark ignition on the radius and mass concentration of particles and propane content in the boron gas suspension are obtained. Dependences between the steady flame propagation velocity in a boron powder suspension in a propane-air mixture on particle radius and particle mass concentration are obtained, and the propane content in a boron gas suspension is determined. Quantitative correspondence of the computational and theoretical values of the flame propagation velocity in a boron powder suspension in a propane-air mixture with known experimental data has been obtained