(37c) Pyrolysis, Laminar Flame Speeds, and Ignition Delay Times for Isopropyl Nitrate

This paper presents experimental and modeling studies on the pyrolysis, laminar flame speeds, and ignition delay times of isopropyl nitrate (iPN) and isopropyl nitrate blended with propane over a broad range of conditions.Pyrolysis experiments were performed in the shock tube at Brown University using the laser schlieren densitometry diagnostic behind the incident shock at temperatures between 700 -- 1000 K and pressures of 60, 120, and 240 Torr. Flame speed measurements were performed at the CNRS-Orleans in a spherical bomb chamber (diameter of 476 mm) at initial pressures of 0.5 and 1.0 bar and equivalence ratios between 0.6 and 1.8. Ignition delay times were measured in the heated, high-pressure shock tube at the CNRS-Orleans for equivalence ratios of 0.5, 1.0, and 1.5, with iPN:C3H8 ratios of 0%, 1%, and 10% between 1000 -- 1500 K and nominal reflected shock pressure of 20 atm. iPN decomposition rate coefficients were computed using RRKM/ME theory. These rate constants were incorporated into a new mechanism, which combines a recently developed C0-C3 mechanism of Jim Miller and coworkers with the nitrogen mechanism of Peter Glarborg. Following the initial cleavage of the O-NO2 bond, the resulting isopropyloxy radical rapidly dissociates to acetaldehyde + methyl radical. The model is in excellent agreement with the data. At the largest equivalence ratios, the model begins to diverge, suggesting that further work needs to be done under these conditions.