Methods and tools for the characterisation of a generic jet fuel

Abstract

The demand for producing environmentally friendly jet fuels raises the question how to design a jet fuel that matches predefined properties. Targets to be matched are e.g. energy content or less harmful emission characteristics. A further major challenge for the production of new synthetic jet fuels is their availability for the required certification process in sufficient quantities within an appropriate time frame and at reasonable cost. This implies the need for tools for the formulation of synthetic jet fuels which have mostly a component pattern that differs from Jet A-1 made from crude-oil. In the present work, to address these challenges, a new approach will be presented in order to be able to design a synthetic jet fuel from scratch with preselected and well-defined physical and chemical properties: The development of a chemical kinetic reaction mechanism able to describe the oxidation of a generic fuel consisting of only a few representative components of the major molecule classes occurring in jet fuels. N-dodecane, cyclohexane, and isooctane were chosen as single fuel components, and their global combustion properties, i.e. laminar burning velocity and ignition delay time, were measured. These experimental data were used for the validation of the reaction mechanisms, first developed for each single fuel component, and then combined to the reaction mechanism for the generic fuel under consideration. The last step is the further optimization and reduction of the generic fuel reaction mechanism to ensure its suitability for the integration in numerical simulation to tackle the combustion of a synthetic fuel under practical conditions, e.g. in CFD simulations.

Combustion kinetics of alternative jet fuels, Part-II: Reaction model for fuel surrogate

“…34 for different ignition delay times and laminar flame speeds. The ignition delay times of n-and isoparaffins are similar at high temperatures whereas small variation is observed at lower temperatures considering the experimental setup allows measurements of ignition delay times up to 30 ms depending on the temperature [29]. Compared to all cyclic compounds, except toluene which shows distinctive slower ignition times, all hydrocarbons shows similar values at higher temperatures.…”

“…The details of modeled conditions of each experiment are tabulated in the supplemental material. In-house [28][29][30][31][32][33] Literature studies…”

Measurement and simulation of sooting characteristics by an ATJ-SKA biojet fuel and blends with Jet A-1 fuel in laminar non-premixed flames

“…The surrogate for Jet A-1 is based on three criteria suggested by Li et al [25] in their study on the validation of surrogates for jet fuel based on chemical deconstruction methodology: (1) atomic composition and H/C ratio; (2) degree of unsaturation (DoU), defined as u=1+n-m/2 for a hydrocarbon denoted as CnHm [26]; (3) fraction of cyclic alkane and aromatics. The surrogate for the biojet is formulated using the four-component model (n-dodecane, iso-octane, cyclohexane, n-propyl benzene) proposed by Richter et al [27]. The reduced number of species and mechanism make the surrogate suitable for CFD modelling.…”