Combustion gaseous

M. L. Bernard et al, CRAcadSci, Ser C, 272 (26), 2112-15 (1972) CA.75, 101675 (1971) A generalization of the previously described (Bernard et al, 1971) ablation theory (for AP) combustion to include AP-based solid propints provides satisfactory fits to the exptl data of M. Summerfield et al (1960), with reproduction of the two distinct pressure regimes observed in the combustion of AP-based powders between 0 and 100 bars. The solid binding agent is assumed to be easily pyrolyzable, with each mol producing several combustible gaseous mols, as in the case of pyrolytically degrading polymers... 

The burning of fuels involves a combination of thermal decomposition (dominant when combusting solid fuels) and hydroxylation (dominant when combusting gaseous fuels), as part of the overall process. 

Semenov first considered the progress of the reaction of a combustible gaseous mixture at an initial temperature T0 in a vessel whose walls were maintained at the same temperature. The amount of heat released due to chemical reaction per unit time (qr ) then can be represented in simplified overall form as... 

Fig. 12.11 shows the structure of a rocket plume generated downstream of a rocket nozzle. The plume consists of a primary flame and a secondary flame.Fil The primary flame is generated by the exhaust combustion gas from the rocket motor without any effect of the ambient atmosphere. The primary flame is composed of oblique shock waves and expansion waves as a result of interaction with the ambient pressure. The structure is dependent on the expansion ratio of the nozzle, as described in Appendix C. Therefore, no diffusional mixing with ambient air occurs in the primary flame. The secondary flame is generated by mixing of the exhaust gas from the nozzle with the ambient air. The dimensions of the secondary flame are dependent not only on the combustion gas expelled from the exhaust nozzle, but also on the expansion ratio of the nozzle. A nitropolymer propellant composed of nc(0-466), ng(0-369), dep(0104), ec(0 029), and pbst(0.032) is used as a reference propellant to determine the effect of plume suppression. The burning rate characteristics of the propellants are shown in Fig. 6-31. Since the nitropolymer propellant is fuel-rich, the exhaust gas forms a combustible gaseous mixture with the ambient air. This gaseous mixture is ignited and afterburning occurs somewhat downstream of the nozzle exit. The major combustion products in the combustion chamber are CO, Hj, CO2, N2, and HjO. The fuel components are CO and H2, the mole fractions of which at the nozzle throat are co(0.47) and iH2(0.24).

Intermittent Detonator Device. An analytical experimental investigation was conducted to determine the operating characteristics of an intermittent-combustion device employing gaseous detonative combustion. Gaseous propane air... 

A combustion aerosol differs from a premixed, combustible gaseous system in that it is not uniform in composition. The fuel is present in the form of discrete particles, which may have a range of sizes and may move in different directions with different velocities than the main stream of gas. This lack of uniformity in the unburned mixture results in irregularities in the propagation of the flame through the spray and, thus, the combustion zone is geometrically poorly defined. 

In an overwhelming majority of cases, heated polymers decompose into combustible gaseous products. The latter diffuse into the oxidative environment, mix and react with oxygen. Therefore, the self-enhancing exothermal reaction responsible for the heat generation and initiation of polymer combustion is in most cases a homogeneous gas phase reaction In order to stress this particular feature of the reactions between... 

Two thermal devices co-exist one consists of a burner fed by a combustible gaseous mixture, the other is a type of small tubular electric oven. In the first assembly, used for the majority of elements, an aqueous solution of the sample is nebulized and then introduced into the flame at a constant rate. In the second, the sample is deposited in a small graphite hollow rod open at both ends, where it is volatized. This more expensive assembly has a greater sensitivity toward refractory elements (V, Mo, Zr). In both methods the optical path source/detector pass through the region containing a tiny cloud of atoms gas in the free state. 

Dilution or suppression of flaming decomposition products. Flame-retardants producing non-combustible gaseous decomposition products at the ignition temperature cause a dilution of the combustibles, i.e. they raise the lower limit concentration of ignition. 

The main chains of conventional polymers consist of carbon atoms, interrupted possibly by oxygen or nitrogen atoms. These macromolecules are thermoplastics and decompose at relatively low temperatures into combustible gaseous products. 

B.E. Gelfand, S.V. Khomik, A.M. Bartenev, H. Gronig, H. Olivier, Detonation and deflagration initiation at the focusing of shock waves in combustible gaseous mixture. Shock Waves 10(3), 197-204 (2000)... 

Let us consider ways of determining the detonation concentration limits in binary combustible gaseous fuel + air mixtures. Calculation of the detonation limits in HCO mixtures can be performed using the one-dimensional Zeldovich model that takes into account energy losses caused by friction and heat-exchange with the duct walls [27]. 

The use of industrial microwave systems avoids combustible gaseous by products thus, ehminating the need for any environmental permits and improving working conditions. 

Plasma arc-jet and oxyacetylene torch ablation tests are much more convenient for operations and with much lower cost, which therefore are often used for primary evaluations of materials about their thermal shock resistance and ablation resistance properties . The difference between these two methods is their gaseous composition and flow speed. A plasma of air may exhibit ultra high temperatures above 5000°C and high velocities of 2 Mach but with ionized air atmosphere. On the other hand, the generally used oxyacetylene torch is of combustion gaseous products of carbon mono/dioxide, water vapor, OH and active hydrocarbon species with gas velocity less than 1 Mach and temperatures above 3000°C. A HVOF torch exhibits... 

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