Detonations in hydrocarbon fuel blends

A study of detonations in high-molecular weight hydrocarbon fuels of interest to pulse detonation engine applications was performed in a 280-mm diameter, 7.3-m long facility. Detonation pressure, wave speed, and cell width measurements were made in JP-10 mixtures and in mixtures representative of the decomposition products of JP-10. Experiments were performed in vapor-phase JP-10 mixtures at 353 K over a range of equivalence ratios (0.7 ≤ φ ≤ 1.4), nitrogen dilutions (fuel-oxygen to fuel-air), and initial pressures (20–130 kPa). The cell widths of the JP-10 mixtures are found to be similar to those of propane mixtures. A fuel blend representative of thermally decomposed JP-10 was studied at 295 K. This blend consisted of hydrogen, carbon monoxide, methane, acetylene, ethylene, and hexane with varying fractions of oxygen and nitrogen. The measured cell width of the fuel blend-air mixture is about half that of JP-10-air. The addition of components of the fuel blend (acetylene, ethylene, and methane) to JP-10 in air at 353 K was characterized. Nitrogen diluted mixtures of stoichiometric hexane-oxygen were studied and the cell widths for hexane-air and JP-10-air are found to be comparable. The addition of lower molecular weight fuels (hydrogen, acetylene, ethylene, and carbon monoxide) to hexane-air was investigated. The measured cell width decreases, indicating increased sensitivity to detonation, with increasing fraction of hydrogen, acetylene, and ethylene, in order of effectiveness. The addition of a small fraction of carbon monoxide produces a small decrease in the cell width, but addition of more than about 75% (by fuel mass) carbon monoxide results in a significant increase in cell width. Carbon monoxide is a principal intermediate product of hydrocarbon combustion yet there are relatively little cell width data available. Cell width measurements were made in carbon monoxide-air mixtures with the addition of hydrogen or hydrocarbons (acetylene, ethylene, and hexane). A linear relationship is found between the cell width and the reaction zone length when it is defined as the location of the peak in hydroxyl mole fraction.

[1]  J. C. Krok.  Jet initiation of deflagration and detonation , 1997 .

[2]  Shock Tube Ignition Time Measurements for N-Heptane/O*/Ar and JP-1 O/Oz/Ar Mixtures -, , 1999 .

[3]  Forman A. Williams,et al.  Chemical-kinetic descriptions of high-temperature ignition and detonation of acetylene-oxygen-diluent systems , 2001 .

[4]  Charles K. Westbrook,et al.  Chemical kinetics of hydrocarbon oxidation in gaseous detonations , 1982 .

[5]  K. Ramamurthi,et al.  On the concept of the critical size of a detonation kernel , 1976 .

[6]  F. Fineschi,et al.  Turbulent jet initiation of detonation , 1991 .

[7]  C. Westbrook,et al.  Detonability of hydrocarbon fuels in air , 1991 .

[8]  Alexander Burcat,et al.  Kinetics of Hexane Combustion in a Shock Tube , 1996 .

[9]  C. Westbrook,et al.  A Comprehensive Modeling Study of n-Heptane Oxidation , 1998 .

[10]  R. Akbar,et al.  Mach reflection of gaseous detonations , 1997 .

[11]  G. B. Kistiakowsky,et al.  Gaseous Detonations. V. Nonsteady Waves in CO–O2 Mixtures , 1952 .

[12]  G. O. Thomas,et al.  Initiation of detonation by steady planar incident shock waves , 1981 .

[13]  J. Nicholls,et al.  Aerodynamic shattering of liquid drops. , 1968 .

[14]  R. Akbar,et al.  Effects of nitrates on hydrocarbon-air flames and detonations , 2001 .

[15]  R. Lathe.  Phd by thesis , 1988, Nature.

[16]  R. Bar-Or,et al.  The reaction zone structure of cylindrical detonations in monodisperse sprays , 1982 .

[17]  Theodore A. Brabbs,et al.  Fuel-rich catalytic combustion of a high density fuel , 1993 .

[18]  Joseph E. Shepherd,et al.  Validation of Detailed Reaction Mechanisms for Detonation Simulation , 2000 .

[19]  F. A. Williams.  Structure of Detonations in Dilute Sprays , 1961 .

[20]  D. White,et al.  Structure of gaseous detonation. IV. Induction zone studies in H2-O2 and CO-O2 mixtures , 1965 .

[21]  C. K. Westbrook,et al.  Measurements of cellular structure in spray detonation , 1991 .

[22]  G. B. Kistiakowsky,et al.  Gaseous Detonations. IX. A Study of the Reaction Zone by Gas Density Measurements , 1956 .

[23]  R. I. Soloukhin,et al.  Chemical Kinetics of Hydrogen-Air-Diluent Detonations , 1986 .

[24]  R. Knystautas,et al.  The critical tube diameter for detonation failure in hydrocarbon-air mixtures☆ , 1982 .

[25]  K. W. Ragland,et al.  Heterogeneous detonation supported by fuel fogs or films , 1971 .

[26]  Anthony M. Dean,et al.  A shock tube study of the H2/O2/CO/Ar and H2/N2O/CO/Ar Systems: Measurement of the rate constant for H + N2O = N2 + OH , 1978 .

[27]  R. J. Kee,et al.  Chemkin-II : A Fortran Chemical Kinetics Package for the Analysis of Gas Phase Chemical Kinetics , 1991 .

[28]  W. C. Gardiner.  Gas-phase combustion chemistry , 2000 .

[29]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[30]  John H. S. Lee,et al.  Dynamic Parameters of Gaseous Detonations , 1984 .

[31]  M. Nettleton.  Gaseous Detonations , 1987, Springer Netherlands.

[32]  Ericka Stricklin-Parker,et al.  Ann , 2005 .

[33]  I. Moen,et al.  Detonation Length Scales for Fuel-Air Explosives , 1983 .

[34]  R. I. Soloukhin,et al.  The Influence of Physical Boundaries on Gaseous Detonation Waves , 1986 .

[35]  C. Westbrook,et al.  Gaseous hydrocarbonair detonations , 1991 .

[36]  James Arthur Nicholls,et al.  Drop-size effects in spray detonations , 1969 .

[37]  B. Myers,et al.  Oxidation of CO. II. Influence of H2 on the Induction Period Preceding Rapid CO2 Formation in Shock‐Heated CO–O2–Ar Mixtures , 1965 .

[38]  J. Shepherd,et al.  Jet Initiation of Deflagration and Detonation in Stoichiometric H_2-O_2-N_2 Mixtures , 1999 .