EXPERIMENTAL STUDY OF REACTION OF ETHANOL WITH OXYGEN BEHIND SHOCK WAVES USING ATOMIC RESONANCE ABSORPTION SPECTROSCOPY METHOD

The kinetics of reaction of C2H5OH with N2O behind shock waves is studied. The quantitative measurements of the time profiles of concentration of O atoms were carried out by the method of atomic resonance absorption spectroscopy (ARAS) using resonance vacuum-ultraviolet line of O-atom at 130.5 nm. For the calibration of absorption intensity of oxygen atoms depending on its concentration, the special series of experiments in the mixture containing different amounts of N2O in Ar was carried out at T = 2100 ± 50 K when molecule of N2O is completely dissociated. An experimental study of the appearance and consumption of oxygen atoms during the reaction of ethanol with oxygen in mixture 10 ppm N2O + (10 ... 0.1) ppm C2H5OH + Ar at temperatures of 16002300 K and pressures of 200-300 kPa have been carried out. A kinetic analysis of obtained data was performed using the Chemkin package.

DEFLAGRATION-TO-DETONATION TRANSITION IN A STRATIFIED SYSTEM “GASEOUS OXYGEN-LIQUID FILM OF N-DECANE”

Deflagration-to-detonation transition (DDT) in the system “gaseous oxygen- liquid film of n-decane” ' with a weak ignition source was obtained experimentally. In a series of experiments with ignition by an exploding wire that generates a weak primary shock wave (SW) with a Mach number ranging from 1.03 to 1.4, the DDT with the detonation run-up distances 1 to 4 m from the ignition source and run-up time 3 ms to 1.7 s after ignition was observed in a straight smooth channel of rectangular 54 x 24-millimeter cross section, 3 and 6 m in length with one open end. The DDT is obtained for relatively thick films with a thickness of 0. 3-0.5 mm, which corresponds to very high values of the overall fuel-to-oxygen equivalence ratios of 20-40. The registered velocity of the detonation wave (DW) was 1400-1700 m/s. In a number of experiments, a high-velocity quasi-stationary detonation-like combustion front was recorded running at an average velocity of 700-1100 m/s. Its structure includes the leading SW followed by the reaction zone with a time delay of 90 to 190 s. The obtained results are important for the organization of the operation process in advanced continuous-detonation and pulsed-detonation combustors of rocket and air-breathing engines with the supply of liquid fuel in the form of a wall film.

THE ROLE OF BUBBLE PULSATIONS IN PROCESSES OF GENERATION OF THRUST PULSES FOR WATER MOVERS

The results of experiments on measurements of pulses of thrust force and bubble pulsations generated on a flat thrust wall due to combustion of a stoichiometric propane-oxygen mixture are presented.

THERMAL BEHAVIOR AND IGNITION OF HIGH-ENERGY MATERIALS CONTAINING B, ALB2, AND TIB2

The paper presents the results of ignition and thermal behavior for samples of high-energy materials (HEM) based on ammonium perchlorate (AP) and ammonium nitrate (AN), active binder and powders of Al, B, AlB2, and TiB2. A CO2 laser with a heat flux density range of 90-200 W/cm2 was used for studies of ignition. The activation energy and characteristics of ignition for the HEM samples were determined. Also, the ignition delay time and the surface temperature of the reaction layer during the heating and ignition for the HEM samples were determined. It was found that the complete replacement of micron-sized aluminum powder by amorphous boron in a HEM sample leads to a considerable decrease in the ignition delay time by a factor of 2.2-2.8 at the same heat flux density due to high chemical activity and the difference in the oxidation mechanisms of boron particles. The use of aluminum diboride in a HEM sample allows one to reduce the ignition delay time of a HEM sample by a factor of 1.7-2.2. The quasi-stationary ignition temperature is the same for the AlB2-based and AlB12-based HEM samples.

ON THE MECHANISMS OF POROUS SILICON COMBUSTION IN OXYGEN AND AIR ATMOSPHERE WHEN SODIUM PERCHLORATE IS INCORPORATED IN PORES

The processes of pSi ignition and combustion in oxygen are described. When spark ignition in the porous layer releases the Joule heat, it leads to a significant heating-up of the breakdown region.

NUMERICAL SIMULATION OF THE EFFECT OF INITIAL NONUNIFORMITY AND FLUCTUATIONS OF FUEL CONCENTRATION ON COMBUSTION STABILITY AND NOX AND CO EMISSION IN A LEAN PREMIXED METHANE/AIR COMBUSTOR

The effect of initial nonuniformity and fluctuations of fuel concentration on the combustion stability and NOx and CO emission in the model combustion chamber was analyzed with the use of previously developed simple and computationally inexpensive Large Eddy Simulation (LES) methodology for simulation of three-dimensional unsteady turbulent flows with premixed combustion of methane-air mixture in low-emission combustion chamber which geometry is represented by channel with the backward facing step. Typical sizes of the combustion chamber, flow parameters, turbulence level, and method of flame front stabilization are close to those of full-sized industrial combustors.

NUMERICAL INVESTIGATION OF THE INFLUENCE OF WATER DROPS ON THE STRUCTURE OF A DETONATION WAVE IN THE METHANE-AIR MIXTURE

The results of numerical studies of the effect of water injection on the parameters of detonation waves in gas combustible mixtures are presented.

SIMULATION OF THE AIR-METHANE COAL DUST MIXTURE COMBUSTION IN THE SWISS-ROLL BURNER

One of the ways to utilize coalmine methane containing coal particles is to use it as a fuel for recuperative type burners that allow sustaining combustion of a lean methane-air mixture. The aim of the work is to study the steady combustion modes of a methane-air mixture containing coal particles in a Swiss-roll burner depending on the feed rate of the mixture and the parameters of the supplied coal-methane-air mixture. The paper considers numerical simulation of the combustion process of the methane-air mixture containing coal dust in a Swiss-roll burner of the recuperative type.

COMBUSTION OF A FROZEN MIXTURE OF BI-DISPERSED ALUMINUM-WATER POWDER

The paper presents a model of combustion of a frozen mixture of nano- and micronsized aluminum powders with water.

SIMULATION OF SUPERSONIC MIXING IN BURROWS-KURKOV COMBUSTOR BY USING SPALART-ALLMARAS REYNOLDS-AVERAGED NAVIER-STOKES METHOD

A numerical model of the turbulent mixing process between two parallel supersonic flows is considered. Model problem of hydrogen injection into the inert gas flow with Mach number M = 2.44 in the Burrows-Kurkov combustor is simulated in two and three dimensions for validating the Spalart-Allmaras (SA) turbulence model and diffusion model computational algorithms for multicomponent gas mixture. The system of averaged Navier-Stokes equations, closed with the turbulence model equation, is solved with the hybrid explicit-implicit LU-SGS-GMRES algorithm. Obtained results are compared with experimental and computational data.