Transition from Deflagration to Detonation and Effect of Heat and Mass Addition on the Parameters of a Subsonic Flow through a Duct.

摘要

The mechanism of the transition from deflagration to detonation was investigated by searching for a correlation between the detonation induction distance and various properties of the unburned mixture such as density, temperature, speed of sound, and the energy transfer to the gas behind the wave front. The magnitudes of theoretically calculated energy transfer in steady waves were compared with experimentally determined induction distances for various hydrogen-oxygen-inert gas mixtures at 1 atm and initial temperatures ranging from 140 to 300 K. The energy transfer was also calculated for pressures ranging from 0.1 to 5 atm. It was found that the induction distances decrease somewhat when the initial pressure is increased but decrease greatly when the initial temperature is decreased. However, more experimental data are needed for formulation of a quantitative relationship between induction distance and the initial properties of the combustible gas mixture. Computational techniques were developed to calculate the changes of the initial static pressure of subsonic flows of air through constant areas ducts which are caused by heat and mass addition. These data provide information which wil be used to predict the effect of fuel flow changes in turbojet combustion chambers and/or afterburners on the performance of high efficiency compressors.