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Title: Marginal detonation in hydrocarbon-oxygen mixtures
Author: Michels, Henricus Josephus
Awarding Body: University of London
Current Institution: Imperial College London
Date of Award: 1967
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Detonation velocities and detonation limits have been established for gaseous mixtures of oxygen with hydrogen; with saturated aliphatic hydrocarbons in the series methane, n-propane, n-butane and neo-pentane; and with propylene. For ambient pressure and temperature and with initiating impact from detonating stoichiornetric hydrogen - oxygen, the following limits in mole % have been observed in a 1-inch- diameter tube : Hydrogen 15.8 and 920 9% Methane 8.25 and 55.8% n-Propane 2.50 and 42.50% n-Butane 2.05 and 37.95% neo-Pentane 1.50 and 33.00% Propylene 2.50 and 50.0% Comparable results for the systems oxygen-ethane and oxygenethylene, collected from other reliable sources, have been included. For the complete composition region aspects of detonation propagation have been related to shock strength. Results for the hydrocarbon containing systems have been normalised on the basis of homologous similarity of the fuel molecules, leading to extensive correlation of the results obtained for the different systems. For the hydrodynamic stable regimes, comparison of results calculated for homologous related initial mixtures reveals a striking correspondence in the state parameters and composition of the C-J condition and of the final state of the reaction products behind the rarefaction wave. For conditions marginal to detonation propagation, normalisation of results on the basis of homology extends to the actual limit compositions for the various systems. It is shown that, especially at the fuel-lean limits, marginal conditions can be correlated to a critical temperature rise of about 1300°Kr 1200°K. For low-molecular weight aliphatic hydrocarbons a somewhat higher temperature rise is required. The possibility is discussed that this requirement is related to the critical rate of a cracking mechanism in the overall bond rearrangement which releases the energy necessary for continued propagation of the detonation wave. For the fuel-rich limits it appears more likely that stability factors, related to modes of solid condensation, determine the remarkable uniform limit composition observed for the normalised systems of oxygen with higher saturated hydrocarbons and with propylene. Suggestions for further investigation of the subject are made.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available