Combustion kinetics of alternative fuels, Part-IV: Extending reaction mechanism “DLR Concise” to include oxygenates components

In our previous work on hydrocarbons (Kathrotia et al., Fuel 2021;302:120736) and jet fuels (Kathrotia et al., Fuel 2021;302:120737) the molecular fuel composition was shown to be an important aspect of understanding the fuel combustion chemistry and, more importantly, the emission behavior. In this extension, we elaborate our high-temperature jet fuel surrogate reaction mechanism (referred hereafter as DLR Concise) to include the chemical class of oxygenated hydrocarbons for transportation fuels. These oxygen containing species have been widely investigated in ground transportation fuels. With DLR Concise we aim for a flexible reaction model for alternative fuel surrogates; a single reaction model with the target application to both aviation- as well as transportation-fuels.

The main focus of this work is to describe the reaction kinetics of oxymethylene ethers (OME_x, x = 0–5) in low to high temperatures. OMEs are promising alternative fuels that can be derived from a variety of sustainable sources. The absence or reduction of C-C bonds makes them attractive for the reduction of soot precursors and soot emissions. The reaction model of OMEs presented in this work is extensively validated against wide-ranging experiments both in-house and from literature. The main purpose of the DLR Concise is to provide a reaction mechanism with a large degree in flexibility to simulate various fuel surrogates (existing and new) and predict pollutants for the fuel assessment based on fuel molecular structure.

A comprehensive model validation as well as new in-house experimental data set on C₁-C₄ alcohols and primary reference fuel (PRF90) measured in high-temperature flow reactor is available as supplemental material.