A HyChem combustion model of methyl decanoate

Abstract

Liquid biofuels are promising carbon-neutral fuels, which contribute to the realization of low-carbon utilization of organic fuels. Due to the difficulty in developing kinetic models for liquid biofuels with complex high molecular components, short-chain fuels are often used as surrogate fuels to study the chemical kinetics of biofuels such as biodiesels. But this approach is complex to model and need to consider the kinetic coupling of the fragments of fuel components. The HyChem approach, which considers the combustion characteristics of the fuel directly, has been proposed to model the combustion of real multi-component and single-component hydrocarbon fuels. It describes the fuel decomposition with a lumped model and the oxidation of pyrolysis fragments with a detailed kinetic model. To preliminarily test the feasibility of the HyChem approach to oxygenated fuels, it was applied to the combustion modeling of methyl decanoate, a typical methyl ester and an important biodiesel surrogate, and the model parameters were constrained by speciation data from literature. Special attention was paid to the evolution of the oxygen element. The results show that the pyrolysis and oxidation of methyl decanoate are two separable processes in time and space, and the methyl decanoate HyChem model predictions had a reasonably good agreement with experimental measurements of speciation, ignition delay time, and flame speeds. To further test the application of HyChem method for biodiesel, we also make a preliminary attempt for methyl palmitate, which is a real biodiesel component. These tests suggest that the HyChem method can be applied to more oxygenated fuels, which provides an efficient modeling approach for complex biofuel combustion.