Detonation Initiation by a Gradient Mechanism in Propane-Oxygen and Propane-Air Mixtures

Abstract

An experimental study of detonation initiation by high-voltage nanosecond gas discharge has been performed in smooth detonation tubes. A gradient mechanism was used to initiate detonations in stoichiometric propane-oxygen mixtures with different nitrogen dilution and in propane-air mixtures. Initial pressures from 0.2 to 1 bar have been tested. Detonation was formed within 4 transverse tube sizes at initial pressures higher than 0.2 bar for the propane-oxygen mixture and higher than 0.8 bar for the diluted mixture with 40% of nitrogen. The discharge energy inputs were 0.2-0.3 J. Combined with the focussing effect of the converging reducer, the gradient mechanism of detonation formation similar to the one suggested by Zeldovich has been shown to be the governing process. For the mixture with air, a detonation tube with an annular discharge chamber has been designed and tested. The results of the tests will follow shortly.

On the possibility of burning acceleration in the combustion chambers of advanced jet engines by deeply subcritical microwave discharge

“…Панацеей при решении всех этих задач может служить применение камер сгорания с детонационным горением, исследования которых ведутся во всем мире [7]. Активно изучаются различ-ные способы интенсификации горения, в том числе и перехода медленного горения в детонацию [8], а также инициирования детонации при помощи СВЧ-разряда [9]. Пока детонационные технологии не соз-даны, актуальна разработка экономичных методов интенсификации обычного медленного горения.…”

Plasma-assisted ignition and deflagration-to-detonation transition

“…An experimental demonstration of a longitudinal, high-voltage, nanosecond, gas-discharge application for initiation of detonation was proposed by Starikovskii [37] and performed by Starikovskiy and co-workers [21,[54][55][56][57][58][59][60][61].…”

“…However, the DDT time was significantly longer and amounted to 150 ms. At the same time, ICCD imaging showed that the ignition did not occur simultaneously over the channel. Instead, a flame was seen originating in the region closest to the high-voltage electrode after a delay of over 50 ms An experimental study of detonation initiation by high-voltage, nanosecond gas discharge has been performed in a smooth detonation tube with a four-channel discharge chamber designed to enable a gradient initiation mechanism [59,60]. Stoichiometric propane-oxygen mixtures diluted by nitrogen were used at initial pressures from 0.2 to 1 bar.…”