Global sensitivity analysis of n-butanol ignition delay times to thermodynamics class and rate rule parameters

Abstract

duce variabilities in ignition delay time that are as large as those associated with kinetic rate uncertainties.

Higher Alcohol and Ether Biofuels for Compression-Ignition Engine Application: A Review with Emphasis on Combustion Kinetics

“…Besides the importance of kinetic rate parameters, the refinement of thermochemical property data of fuel-specific intermediates of low-temperature oxidation has been highlighted by multiple recent studies to be very important for accurate model predictions at low and intermediate temperatures as well. ,− Employing the local sensitivity analysis on thermochemistry, , sensitivities of ignition delay times on enthalpies of formation of fuel-specific species were computed as part of the present study for stoichiometric n -pentanol/air and DNBE/air mixtures at 20 bar and 909 K by using the mechanisms of Heufer et al and Cai et al, respectively. At the selected condition, the impact of thermochemistry is expected to be significant. , For both cases, sensitivity analyses on fuel-specific elementary reactions were carried out as well.…”

A tangent linear approximation of the ignition delay time. II: Sensitivity to thermochemical parameters

“…Our main objective is to estimate the sensitivity of the ignition delay time, τ ign , with respect to infinitesimal perturbations in the stochastic germ parametrizing the uncertainty in species enthalpies and entropies [2][3][4]8]. The latter are typically expressed using NASA polynomials, according to [17,18]:…”

“…Following [8], with the molar enthalpy and entropy of species i respectively represented as in ( 3) and ( 4), we assume that parameters a 5,i and a 6,i are uncertain and parametrized using independent canonical random variables η i and σ i , uniformly distributed over [ −1, 1]. The dependence of a 5,i and a 6,i on η i and σ i is expressed as…”

“…In the present analysis of sensitivities to thermodynamic parameters, we focus exclusively on N s = 54 species involved in the thermodynamic classes outlined in [8] and consisting of the fuel and fuel radicals, as detailed in the Supplementary Material. In other words, the cardinality of the sets K h and K s are |K h | = |K s | = 54.…”

“…In contrast to the extensive body of work focusing on the impact of rate parameters, a relatively lower number of studies have addressed the role of thermodynamic properties on mixture reactivity [1][2][3][4][5][6][7][8]. This is a primary focus of the present work.…”