The Low Temperature Oxidation Chemistry of JP-8 and its Surrogates at High Pressure
     Sponsor: Army Research Office
     PIs: Cernansky & Miller

The purpose of this project is to map the effects of chemical variations on the oxidation behavior of JP-8, and to participate in the development of an acceptable surrogate that matches the general behavior of JP-8. In this JP-8 mapping and surrogate development effort, selected JP-8’s, distillate fuels, and neat distillate fuel components will be examined to develop comparative kinetic and mechanistic information in the low and intermediate temperature ranges (600 – 1000 K) and at elevated pressures (up to 20 atm). Similarly, the various proposed JP-8 surrogates, components, and their mixtures will be examined as well. These single and multiple component fuels will be oxidized in a pressurized flow reactor and stable intermediate and product species will be identified and quantified using permanent gas analyzers, gas chromatography, gas chromatography/ mass spectrometry (GC/MS), and on-line Fourier Transform Infrared Spectrometry (FT-IR). In addition, in-situ techniques such as Cavity Enhanced Magneto-Optic Rotation (CEMOR) will be employed as appropriate to make measurements of selected stable and radical species in order to provide key mechanistic information. The experimental results will be used to develop appropriate detailed and reduced kinetic models for the ignition and oxidation of these fuels. Ultimately, these low and intermediate temperature experimental and modeling results will be coupled with the efforts of other research groups to provide a comprehensive understanding of the oxidation and combustion behavior of JP-8 and its surrogates.

     Recent Reports/Presentations:
          None Available

High Pressure Cool Flames and Auto-Ignition in Microgravity
     Sponsor: NASA
     PIs: Miller, Cernansky & Pearlman 

A ground-based microgravity (μg) study on low-temperature reactions, cool flames and auto-ignition at elevated pressures (1atm P 10atm) is proposed. This work is an extension of the reduced gravity, subatmospheric cool flame studies performed by Pearlman and co-workers. Extensions to elevated pressures will allow us to explore cool flames at conditions closer to the pressures of the critical applications in combustion systems. The program aims to isolate the roles of species and thermal diffusion on reaction front structure, stability, and evolution. On Earth, natural convection in unstirred, static reactors dominates diffusive transport and complicates the temperature and species concentration profiles. Moreover, these complexities cannot be effectively suppressed in terrestrial environments by reducing the pressure and/or reaction vessel size, i.e., Ra. At reduced gravity, however, buoyant convection can be effectively suppressed, the problem reduced from two (or three) dimensions to one-dimension, and modeled exactly.

The specific objectives of the proposed study are to:
(1) Develop ignition diagrams (phase-plots of temperature versus pressure and mixture stoichiometry) for heavy hydrocarbon-air and hydrocarbon-oxygen mixtures at elevated pressures in the range of 1-10atm,
(2) Measure and record the one-dimensional flame speed, integrated spatial distribution of uv and visible light, 2D formaldehyde and temperature distribution, and induction times(s) associated with high pressure cool flames and auto-ignition fronts,
(3) Develop chemical kinetic models for high pressure, low-temperature reactions in a microgravity environment and compare the results to the experimental measurements,
(4) Compare the results to those obtained by other researcher efforts that have used CSTR’s, heated flow tubes, and motored engines.

To accomplish these objectives, an international team of researchers with experimental and modeling experience in low temperature oxidation and cool flames has been organized. The proposed approach includes laboratory and reduced gravity experimental development and testing, detailed kinetic modeling, and LIF diagnostic development and implementation.

     Recent Reports/Presentations:
          None Available