Fuel mixtures detonation, equivalence

The transition of deflagration to detonation in mixtures was studied with respect to mixing ratio, pressure and spark energy [1], A study of TNT equivalences in propylene oxide fuel/air explosives is made [2],... 

The mixtures investigated were composed of ethylene-oxygen and ethylene-air at various equivalence ratios and were injected dynamically into the system at the head-end of the test apparatus. A 3.39-micrometer infrared (IR) He-Ne laser was transmitted across the combustor 2.54 cm upstream of the diffraction plane so that the fuel-oxygen to fuel air interfaces could be located spatially and characterized temporally. The typical mixture transition interface between the fuel-oxygen and fuel-air mixtures was approximately 6 cm in length. All gaseous flow rates were determined from metering orifices. Detonation wave speeds were... 

For effective use of the developed model, information on the induction time and droplet evaporation rates, as a function of the local conditions in the shock-heated mixture, is needed. Currently, in the absence of such information, parametric studies with various constant induction times and droplet evaporation rates have been carried out. The predicted detonation velocity as a function of the initial droplet size is shown in Fig. 11.6 for a nominalJP-lO-oxygen mixture with an equivalence ratio of 0.12. A d -law evaporation with a rate of 0.1 cm /s and an induction time for the fuel-vapor of 1 //s was used for this series of simulations. The velocity deficit observed previously in many experimental studies of multiphase detonations is predicted by the numerical model. In the absence... 

Since hydrogenous mixtures containing hydrocarbons can be used in engines, it is useful to study the detonation velocity in a combustible composite fuel in mixtures with air and oxygen. Such calculations for H2 + CH4 + O2 and H2 + CsHg + O2 were performed in [38] and are illustrated in Figs. 7.30 and 7.31 in detonation velocity (Z9)/equivalence ratio (0) coordinates. It is seen that the difference in detonation velocities between various composite triple mixtures and simple binary mixtures is insignificant [4, 5, 7, 12-59]. 

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