Combustion Characteristics of p-Cymene Possibly Involved in Accelerating Forest Fires

A potential implication of volatile organic compounds (VOCs) emitted by vegetal species has been introduced in the literature to explain accelerating forest fires. The main purpose of this article is to determine the combustion characteristics of a VOC emitted by Rosmarinus officinalis shrubs, namely p-cymene. The emission of this compound is studied for the temperature range 353-475K, and an emission peak is found at 448K. Laminar burning speeds, Markstein lengths, and flame thicknesses are determined using outwardly propagating spherical flames in a combustion chamber at atmospheric pressure. The effects of equivalence ratio (0.8-1.4) and unburned gas temperature (358-453K) are studied. A correlation is proposed to estimate laminar burning speeds as a function of equivalence ratio and temperature. Due to the lack of data concerning the combustion characteristics of p-cymene, our results are compared to experimental data of heavy molecules such as ethylbenzene, iso-octane, and -pinene, and to computed data of JP-10 and n-decane. The computed laminar burning speeds of these last two molecules are obtained using the PREMIX code of the CHEMKIN package.