Combustion and detonation characteristics of hydrazine and its methyl derivatives

Results of experiments on detonation propagation in a rectangular horizontal channel with high ribs on the lower wall are presented. The experiments were performed with acetylene-oxygen mixtures. An interval of initial pressures is found, in which low-velocity detonation with a steady velocity of 0.38-0.55 of the Chapman-Jouguet velocity without losses exists. This detonation wave is a system consisting of a shock wave and a flame. Owing to gas outflow to the layer occupied by the ribs, the flame is maintained at a constant distance from the shock wave, which is approximately equal to the free transverse size of the channel. This distance weakly decreases with increasing initial pressure and is almost independent of the burning rate of the gas at standard temperature.

Section: Test Resultsmentioning

confidence: 99%

Gas detonation in a channel with transverse ribs

Manzhalei

2007

“…Such calculations were performed with the use of the "BEZOPASNOST" ("SAFETY") program [16]. We give only one example of such calculations for a stoichiometric hydrogenair mixture (initial parameters in the settling chamber: p 0 = 21 atm and T 0 = 280 K; the equivalence ratio equals unity) in the cross section X = 0.15 m from the nozzle exit.…”

Section: Calculated Parameters Of the Detonation Wavementioning

confidence: 99%

Detonation waves in a reactive supersonic flow

Васильев

Звегинцев

Nalivaichenko

2006

Self Cite

A supersonic hydrogen-air flow is studied in detail, in particular, the fields of gasdynamic parameters and chemical homogeneity of the mixture in various cross sections of the duct. The processes of excitation and propagation of a detonation wave in the downstream and upstream directions are considered. The detonation-wave velocity with respect to the mixture flow is found to differ from the nominal Chapman-Jouguet velocity for a quiescent mixture: the detonation-wave velocity is higher if the wave moves upstream and lower if the wave moves downstream. Some hypotheses on the reasons for these deviations of the experimentally measured velocity from the nominal value are given.

“…It was with the use of acetylene that carbon condensates in the form of nanoparticles, fullerenes, nanotubes, etc., were obtained. The parameters of combustion and detonation of C 2 H 2 -O 2 and C 2 H 2 -air mixtures in a wide range of acetylene concentrations in the initial mixture were calculated by the Bezopasnost (Safety) computer code [2] with allowance for possible condensation of carbon in the products. For comparison, calculations were also performed with no allowance for carbon condensation, i.e., for all substances considered in the gas phase only.…”

Section: Calculated Parameters Of Combustion and Detonationmentioning

confidence: 99%

Formation of carbon clusters in deflagration and detonation waves in gas mixtures

Васильев

Pinaev

2008

Self Cite

Numerical and experimental results of studying the formation of carbon clusters due to propagation of deflagration and detonation waves in enriched acetylene-oxygen and acetylene-air mixtures are described. Experiments are performed in tubes of different diameters (including tubes filled by a porous medium) with wide-range variations of the initial pressure and the fuel-to-oxidizer ratio. A large variety of carbon clusters formed in different regimes of burning of the mixture is found. A typical size of condensed carbon particles is 15-100 nm. In the case of detonation in a porous medium, the size of carbon particles is 15-45 nm; in some tests, large individual fullerene-type particles 150, 400, and 950 nm in size are formed. The fraction of condensed carbon in the total amount of carbon in the initial mixture is found to depend on the wave type; detonation is characterized by the minimum "yield" of condensed carbon. The amount of condensed carbon increases with increasing acetylene concentration in the mixture and initial pressure. The size of carbon particles in the case of deflagration is greater than that in the case of detonation. Cooling of reaction products decelerates condensation and interrupts the growth of carbon particles.