Experimental and modeling study of the mutual oxidation of N-pentane and NO at low temperature in a jet stirred reactor

The mutual oxidation of n-pentane and nitric oxide (NO) at 500-800K has been studied at the fuel lean condition (φ = 0.5) in an atmospheric jet stirred reactor (JSR). The concentration of NO in the mixture is varied between 0 to 1070ppm. Key oxidation species, like n-pentane, O₂, CO, CO₂, NO, NO₂, CH₂O, C₂H₄, and CH₃CHO are in-situ quantified by using an electron impact molecular beam mass spectrometer (MBMS), a micro-gas chromatograph (µ-GC), and a dual-modulation faraday rotation spectrometer (DM-FRS) simultaneously. The experimental results show that NO has different sensitization characteristics on n-pentane oxidation in three different temperature windows. NO addition delays the onset temperature of low temperature oxidation of n-pentane between 550-650K, weakens the negative temperature coefficient (NTC) behavior in the NTC region (650-750K), but accelerates the high temperature oxidation to be in the intermediate temperature region (750-800K). Combined with a modified n-pentane mechanism (Bugler et al. 2017) and an newly developed NO_x sub-mechanism (Zhao et al. 2019 In press), a new n-pentane/NO_x kinetic model is developed in this paper to predict the experimental results. It shows that the three distinct temperature-dependent characteristics of NO sensitization effects are properly captured using the present model.