SCHLIEREN METHOD OF OPTICAL REGISTRATION OF COMBUSTION TO DETONATION TRANSITION IN GASEOUS MIXTURES

1994 ◽  
Vol 3 (1-6) ◽  
pp. 465-475
Author(s):  
Michael V. Tyurnikov ◽  
Nickolay N. Smirnov
Keyword(s):  
Schlieren Method ◽  
Gaseous Mixtures ◽  
Detonation Transition

Estimation of critical conditions for deflagration-to-detonation transition in obstructed channels filled with gaseous mixtures

2018 ◽  
Vol 13 (6) ◽  
pp. 54 ◽  
Author(s):  
Alexey D. Kiverin ◽  
Ivan S. Yakovenko
Keyword(s):  
Complex Analysis ◽  
Complex Geometry ◽  
Critical Conditions ◽  
Gaseous Mixtures ◽  
Flame Acceleration ◽  
Deflagration To Detonation Transition ◽  
Detonation Transition ◽  
The Stability ◽  
The Given ◽  
Good Agreement

The paper considers the peculiarities of deflagration-to-detonation transition (DDT) in obstructed channels filled with gaseous mixtures. The necessary stage in flame evolution prior to DDT is the stage of flame propagation in so-called “chocked flame” regime. The structure of the chocked flame is studied numerically in details that allows formulating the criterion of its stability. In turn, the stability of chocked flame determines the possibility of further flame acceleration and subsequent DDT. Such a criterion is of purely chemical nature and can be estimated using the parametric study involving simple one-dimensional calculations. It should be however noted that to get the prediction of DDT in real complex geometry one should additionally estimate the particular conditions of chocked flame formation in the given geometry. Moreover, the particular mechanisms of detonation onset should be analyzed. Such a complex analysis involving both chemical criterion and analysis of geometrical conditions is applied to the estimation of DDT possibility in obstructed channels. The obtained results are in a good agreement with available experimental data.

RANKING OF FUEL-AIR MIXTURES IN TERMS OF THEIR PROPENSITYTO DEFLAGRATION-TO-DETONATION TRANSITION

2020 ◽  
Author(s):  
S. M. FROLOV ◽  
◽  
V. I. ZVEGINTSEV ◽  
V. S. AKSENOV ◽  
I. V. BILERA ◽  
...  
Keyword(s):  
Detonation Wave ◽  
The Other ◽  
Practical Application ◽  
Deflagration To Detonation Transition ◽  
Other Hand ◽  
Pressure Gain Combustion ◽  
Reactive Mixture ◽  
Detonation Transition ◽  
The One ◽  
Energy Converting

The term "detonability" with respect to fuel-air mixtures (FAMs) implies the ability of a reactive mixture of a given composition to support the propagation of a stationary detonation wave in various thermodynamic and gasdynamic conditions. The detonability of FAMs, on the one hand, determines their explosion hazards during storage, transportation, and use in various sectors of the economy and, on the other hand, the possibility of their practical application in advanced energy-converting devices operating on detonative pressure gain combustion.

DETONABILITY OF FUEL-AIR MIXTURES IN TERMS OF DEFLAGRATION-TO-DETONATION TRANSITION

2020 ◽  
Author(s):  
S. M. FROLOV ◽  
◽  
V. I. ZVEGINTSEV ◽  
I. O. SHAMSHIN ◽  
M. V. KAZACHENKO ◽  
...  
Keyword(s):  
Natural Gas ◽  
Experimental Method ◽  
Pyrolysis Products ◽  
Ethylene Propylene ◽  
Pulse Detonation ◽  
Detonation Tube ◽  
Standard Pulse ◽  
Detonation Transition ◽  
Run Up ◽  
Propane Butane

A new experimental method for evaluating the detonability of fuel-air mixtures (FAMs) based on measuring the deflagration-to-detonation (DDT) run-up distance and/or time in a standard pulse detonation tube is used to rank gaseous premixed and nonpremixed FAMs by their detonability under substantially identical thermodynamic and gasdynamic conditions. In the experiments, FAMs based on hydrogen, acetylene, ethylene, propylene, propane-butane, n-pentane, and natural gas of various compositions, as well as FAMs based on the gaseous pyrolysis products of polyethylene (PE) and polypropylene (PP) are used: from extremely fuel-lean to extremely fuel-rich at normal temperatures and pressures.

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

2020 ◽  
Author(s):  
S. M. FROLOV ◽  
◽  
V. S. AKSENOV ◽  
I. O. SHAMSHIN ◽  
◽  
...  
Keyword(s):  
Liquid Film ◽  
Ignition Source ◽  
Gaseous Oxygen ◽  
Deflagration To Detonation Transition ◽  
Operation Process ◽  
Continuous Detonation ◽  
Smooth Channel ◽  
Detonation Transition ◽  
Run Up ◽  
X 24

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.

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