V. S. Aksenov

Detonation initiation by shock wave interaction with the prechamber jet ignition zone

255 Detonation initiation in a stoichiometric propane–air mixture by controlled shock wave (SW) interaction with the cloud of hot combustible gas forming upon the discharge of a combustion product jet from the prechamber has been experimentally observed for the first time. It has been shown that detonation initiation requires the careful synchronization of the SW arrival at the cloud with the moment of spontaneous ignition in it.

Deflagration-to-detonation transition in a kerosene-air mixture

The low detonability of jet kerosene–air mixtures is the major obstacle to the development of an air-breathing pulse detonation engine (PDE) [1]. Currently, work is underway to considerably decrease the detonation initiation energy of hydrocarbon fuels, as well as to reduce the predetonation distance and time [2]. On the one hand, to achieve this aim, it is suggested to use active chemical additives to fuels, fuel blends, emulsified fuels, barbotage of fuel with an active gas, preliminary thermal and radiation treatment of fuel, fuel prevaporization, and premixing of fuel with oxygen or air. Notwithstanding the fact that some of these solutions are believed to be promising, their use in PDEs for flying vehicles is limited by severe safety requirements for their operation, weight restrictions, etc. On the other hand, physical methods aimed at reducing the DDT distance and time are currently being studied. It is suggested to use prechamber jet [3] and plasma jet [4] ignition, traveling igniters [5], regular obstacles [6, 7], tubes of near-limiting diameter [7], regular shaped reflectors of shock waves [8], or tube U bends [9] or tube coils [7, 10], as well as different combinations thereof [7, 10, 11].

Detonation Initiation in a Natural Gas-Air Mixture in a Tube with a Focusing Nozzle

It was shown experimentally for the first time that, when an axisymmetric nozzle of special shape is placed in a tube, the shocktodetonation transition in a stoichiometric natural gas-air mixture occurs under normal conditions at a shock wave (SW) velocity at the nozzle inlet exceeding 1150 ± 30 m/s, which corre� sponds approximately to a Mach number of 3.3. This finding is important for the development of newgen� eration burners using pulsed detonative (PD) combus� tion of natural gas, as well as for a better understanding of the dynamics of accidental gas explosions in mine

Wind Tunnel Testing of a Detonation Ramjet Model at Approach Air Stream Mach Number 5.7 and a Stagnation Temperature of 1500 K

The mode of continuous detonation combustion of hydrogen in the annular combustor of a model of a detonation air-breathing ramjet at the approach air stream Mach number 5.7 and a stagnation temperature of 1500 K was experimentally detected for the first time in a pulsed wind tunnel. The thrust and fuelbased specific impulse of the ramjet model were 1550 N and 3300 s, respectively.