Determination of octane number based on parameters of reaction of cool-flame oxidation of hydrocarbons

A detailed analytical study of the cool-flame oxidation of propane has been carried out using a continuous-flow technique with a view to the further elucidation of the mechanism of the low-temperature oxidation of hydrocarbons. The formation of the three theoretically possible aldehydes has been demonstrated and the initially formed peroxide shown to be hydrogen peroxide. Measurements of the yields of the different products formed under varying conditions of temperature, composition and time of contact have been made and correlated with measurements of the luminous intensity and temperature of the flame. The results confirm the earlier conclusions of Norrish (1948) that aldehydes are the important branching agents in the temperature range of 300 to 400°C, and a detailed scheme based on that proposed earlier has been developed to account for the observations. The scheme has further been shown to allow of a simple explanation of the origin of the periodic character of the cool flame in terms of the thermal instability of the normal slow reaction.

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A Theoretical Study on Cool Flame Oxidation as an Effective Way for Fuel Reforming: Emphasis on Ignition Characteristics and Chemical Analysis

Combustion Science and Technology ◽

10.1080/00102202.2021.1978990 ◽

2021 ◽

pp. 1-17

Author(s):

Jiaying Pan ◽

Ruoyue Tang ◽

Jian Gao ◽

Zhandong Wang ◽

Haiqiao Wei ◽

...

Keyword(s):

Chemical Analysis ◽

Theoretical Study ◽

Fuel Reforming ◽

Cool Flame ◽

Ignition Characteristics ◽

Flame Oxidation

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A mathematical model of the cool-flame oxidation of acetaldehyde

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1971.0074 ◽

1971 ◽

Vol 322 (1550) ◽

pp. 377-403 ◽

Cited By ~ 41

Keyword(s):

Mathematical Model ◽

Negative Temperature ◽

Isothermal Oxidation ◽

Limited Range ◽

Detailed Model ◽

Cool Flame ◽

Induction Periods ◽

Cool Flames ◽

Satisfactory Account ◽

Flame Oxidation

A detailed mathematical model of the non-isothermal oxidation of acetaldehyde has been found to give a realistic simulation of (i) single and multiple cool flames, their limits, amplitudes and induction periods; (ii) two-stage ignition; and (iii) the negative temperature coefficient for the maximum rate of slow combustion. A simplified form of the model, valid over a limited range of conditions, has been subjected to mathematical analysis to provide interpretations of the effects simulated by the detailed model. It is concluded that cool flames are thermokinetic effects often, but not exclusively, of an oscillatory nature, and that a satisfactory account of cool-flame phenomena must necessarily take reactant consumption into account.

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Evidence for carbon suboxide, C3O2, as an intermediate product in the cool flame oxidation products of diethyl ether

Combustion and Flame ◽

10.1016/0010-2180(61)90074-8 ◽

1961 ◽

Vol 5 ◽

pp. 65-70 ◽

Cited By ~ 5

Author(s):

L.H.S. Roblee ◽

J.T. Agnew ◽

K. Wark

Keyword(s):

Diethyl Ether ◽

Intermediate Product ◽

Oxidation Products ◽

Carbon Suboxide ◽

Cool Flame ◽

Flame Oxidation

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A Study of HCCI Combustion Characteristics by Using Light Emission and Absorption Spectroscopy

ASME/JSME 2011 8th Thermal Engineering Joint Conference ◽

10.1115/ajtec2011-44282 ◽

2011 ◽

Author(s):

Akira Iijima ◽

Koji Yoshida ◽

Hideo Shoji

Keyword(s):

Air Temperature ◽

Light Absorption ◽

Octane Number ◽

Light Emission ◽

Activity Level ◽

Oxidation Reactions ◽

Temperature Oxidation ◽

Cool Flame ◽

Spectroscopic Measurements ◽

Residual Gas

Light emission and absorption spectroscopic measurements of chemical species were made to investigate the effects of the fuel octane number, residual gas state and intake air temperature on the ignition characteristics of a Homogeneous Charge Compression Ignition (HCCI) engine. The results revealed that the activity level of low-temperature oxidation reactions and the tendency for autoignition to occur can be ascertained by making simultaneous spectroscopic measurements of light emission and absorption at wavelengths corresponding to those of formaldehyde (HCHO). The measured results showed that light absorption attributable to HCHO and faint light emission occur coincidentally with the cool flame. Once the cool flame degenerates, light absorption and emission are moderated. Absorbance declines sharply when autoignition occurs, indicating the consumption of HCHO. Increasing the octane number, raising the intake air temperature and increasing the residual gas fraction all have the effect of weakening the absorbance and light emission intensity of HCHO at the time the cool flame occurs, thereby lengthening the interval from the cool flame to autoignition.

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