Lean Detonation Limit of Sensitized Kerosene Sprays in Air

Abstract

A shock-tube technique was used to determine the lean detonability limit of kerosene sprays in air when the kerosene is sensitized by either propyl nitrate (PN) or butyl nitrite (BN). The technique accounts for the initiation energy and its rate, or power. Monodisperse sprays having droplet diameter of 780 [im are tested in a 5-cm-square tube, 2.7 m in length. An initiation energy of 50 J/cm 2 at a rate of 160 Kw/cm 2 is used, and three equivalence ratios (<()) namely, 0.59, 0.44, and 0.3, are tested. The kerosene is mixed with 10% or 20% of either PN or BN. The results indicate that the addition of PN reduces the limiting (j) so that, for 10% PN, it is between 0.44 and 0.3 and below 0.3 for 20% PN. Erratic behavior was detected when 10% BN was used. However, when 20% BN is mixed with the kerosene, the limiting § is found to be below 0.3. NomenclatureA = driven section area aj = speed of sound of gas in driven section d = drop diameter E = energy E* = critical initiation energy f = droplet shedding frequent /4 = driver length M = Mach number M = initial Mach number