EXPERIMENTAL AND MODELING STUDY OF OXIDATION AND AUTOIGNITION OF BUTANE AT HIGH-PRESSURE

Oxidation and autoignition of stoichiometric, lean (phi = 0.8), and ri ch (phi = 1.2) butane-''air'' mixtures are studied in a rapid compress ion machine between 700-900 K and 9-11 bar. Information is obtained co ncerning cool flames and ignition delays. Product profiles for selecte d major and minor species are measured during a two-stage ignition pro cess. The presence of C4 heterocycles may be connected to isomerizatio n and decomposition of butylperoxy radicals. The experimental results are compared with numerical predictions of an homogeneous adiabatic mo del based on the Pitz-Westbrook comprehensive chemical mechanism of 19 90. The experimental and predicted delays are in the same order of mag nitude. A relatively good agreement is found for the major species pro files. Improvement of the mechanism is needed to account for the minor products. The different paths of OH formation are discussed.