Shock to detonation transition of pentaerythritol tetranitrate (PETN) initially pressed to 1.65 g/cm3

2021 ◽  
Vol 130 (2) ◽  
pp. 025901
Author(s):  
Tariq D. Aslam ◽  
Cynthia A. Bolme ◽  
Kyle J. Ramos ◽  
Marc J. Cawkwell ◽  
Christopher Ticknor ◽  
...  

The deflagration-to-detonation transition (DDT) has been studied in prepared columns of granular secondary explosive. The secondary explosives 2- (5-cyanotetrazolato) pentammine cobalt (III) perchlorate (CP) and pentaerythritol tetranitrate (PETN) were chosen for the study due to their known propensity to undergo DDT within a few millimetres of ignition. Confinement of CP columns within polycarbonate and PETN within metallic confinement fitted with slit windows allowed direct high-speed streak photography of the events. Deflagration and detonation velocities and the run-to-detonation lengths were measured as a function of charge pressed density. Ignition of the explosive column was attained thermally through a copper barrier with a gasless pyrotechnic. Deflagration and detonation velocities were seen to depend strongly upon pressed density with both explosives. There appeared to be a maximum density conducive to DDT with both explosives but no minimum with CP. Studies of DDT continue to have interest for the safe storage and use of reactive materials, and for the development of a detonator based on a secondary explosive.


2019 ◽  
Author(s):  
Peter Andreas Schulze ◽  
Gary Robert Jr. Parker ◽  
Ian Daniel Lopez-Pulliam ◽  
Trevor Alexander Feagin ◽  
Eric Mann Heatwole

Author(s):  
S. M. FROLOV ◽  
◽  
V. I. ZVEGINTSEV ◽  
V. S. AKSENOV ◽  
I. V. BILERA ◽  
...  

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.


Author(s):  
S. M. FROLOV ◽  
◽  
V. I. ZVEGINTSEV ◽  
I. O. SHAMSHIN ◽  
M. V. KAZACHENKO ◽  
...  

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.


Author(s):  
S. M. FROLOV ◽  
◽  
V. S. AKSENOV ◽  
I. O. SHAMSHIN ◽  
◽  
...  

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.


2019 ◽  
Vol 489 (5) ◽  
pp. 461-464
Author(s):  
A. D. Kiverin ◽  
I. S. Yakovenko ◽  
V. E. Fortov

The problem of the detonation formation as a result of unconfined flame propagation is solved numerically. The mechanism of detonation formation is distinguished. It is related to the local formation of shock waves du- ring the linear stage of development of flame front perturbations formed on the surface of the expanding flame front. General criteria of the establishment of the conditions for the detonation transition via the proposed mechanism are formulated.


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