Laminar Flame Speed Measurements of Kerosene-Based Fuels Accounting for Uncertainties in Mixture Average Molecular Weight

Abstract

New laminar flame speed experiments have been collected for some kerosene-based liquid fuels: Jet-A, RP-1, and diesel fuel #2. Accurately understanding the combustion characteristics of these, and all kerosene-based fuels in general, is an important step in developing new chemical kinetics mechanisms that can be applied to these fuels. It is well known that the precise composition of these fuels changes from one production batch to the next, leading to significant uncertainty in the mixture average properties. For example, uncertainty in a fuel blend's molecular weight can have a noticeable effect on defining an equivalence ratio for a typical fuel–air mixture, of the order of 15%. Because of these uncertainties, fuel mole fraction, XFUEL, is shown to be a more appropriate parameter for comparison between different batches of fuel. Additionally, a strong linear correlation was detected between the burned-gas Markstein length and the equivalence ratio. This correlation is shown to be useful in determining the acceptability and accuracy of individual data points. Spherically expanding flames were measured over a range of fuel mole fractions corresponding to equivalence ratios of φ = 0.7 to φ = 1.5, at initial conditions of 1 atm and 403 K in the high-temperature, high-pressure (HTHP) constant volume vessel at Texas A&M University. These new results are compared with the limited set of laminar flame speed data currently available in the literature for this fuel.