Enhancement and Control of Deflagration to Detonation Transition ( DDT ) in binary fuels C 3 H 8 − H 2 / air Mixtures : Application to Propulsion

The Deflagration to Detonation Transition (DDT) that follows the flame acceleration has been investigated for different purposes, namely for safety concerns and for rapid transition in detonation-assisted propulsion systems. Beside its use in rocket propulsion, hydrogen is more and more regarded as an appropriate candidate for propulsive systems. Yet it is highly sensitive to detonation, which is a major concern in terms of safety, especially for its storage. This aspect can be controlled by the addition of a few amount of alkane. The present paper provides experimental data on the DDT of binary fuels C3H8−H2/air mixtures at ambient conditions. This study is aimed at extending the use of H2 in propulsive systems, together with allowing an easier storage of this fuel in terms of safety. The experimental study is based on the measurements of the run-up distance to DDT in a stainless steel cylindrical tube, using a Schelkin spiral. The effects of the spiral length, material, as well as the inner diameter of the tube, are investigated in terms of DDT enhancement. The corresponding criteria λ ≤ d â and L > 7λ are also examined.