Development of a High Temperature Oxidation Mechanism for Bio-Aviation Fuels

Abstract

Almost all current civil and military aviation around the world use a kerosene-type fuel. However one of the alternatives is to use a mixture of petrochemicals and biofuel, especially methyl esters derived from vegetable oil (Fatty Acid Methyl Esters, FAMEs) that given their properties appear to be one of the most suitable for Aviation fuels. Studies were conducted to develop a fundamental and detailed reaction mechanism for the combustion of bio-aviation fuel through a combination of the existing kerosene based reaction mechanism developed previously by the authors (Aviation Fuel Reaction Mechanism v1.1), along with published chemical kinetic mechanisms for methylbutanoate (MB). Methylbutanoate is the simplest FAME that exhibits similar patterns of reactivity to FAME’s of longer carbon chain length typical of those derived from vegetable oils, furthermore it has been the subject of several studies to provide chemical kinetic mechanisms to predict its oxidation behavior. Evaluations of the combined reaction mechanism have been performed using CHEMKIN™ and similar software simulating high temperature/pressure conditions. A comparison between the oxidation processes of the Kerosene and Bio-Aviation fuel was carried out, along with sensitivity analysis to provide insight into some of the differences observed. A similar behaviour was observed for blends of 20%MB/80%Kerosene in the combustion conditions studied, indicating that combustion in current aircraft engines would not be adversely affected by using such a blend.

Theoretical investigation of the performance of alternative aviation fuels in an aero-engine combustion chamber

“…A number of studies have been published in which the performance of these alternative fuels has been examined [4,6,10,11,12,13].…”

“…Detailed oxidation mechanisms for kerosene and biofuel, recently developed by the authors [6], have been employed using the 3D CFD solver.…”

Assessment of the Performance of Alternative Aviation Fuel in a Modern Air-Spray Combustor (MAC)

“…This is important since utilising existing engine technology significantly reduces the cost and time scales for implementation. Other technologies, such as hydrogen although important, need further development and their application on a wider scale is a considerable time away [3,4,12]. One of the main advantages of biofuels is that their use can produce significant savings in carbon dioxide emissions (so long as they are grown and processed in a sustainable way).…”

“…A detailed chemical reaction mechanism AFRMv.2.0 2 describes in the paper by Catalanotti et al [3]; has recently been developed which can represent a number of different aviation fuels including bio aviation fuel. In this work we study its predictive performance for combustion within the MAC combustor.…”

“…Theoretical chemical kinetics studied by the authors [3] shows that at high temperature MB in biofuel is consumed by hydrogen abstraction, with H atoms and O˙, H˙ radicals as the main contributors. Hydrogen abstraction from MB by H atoms is the most sensitive reaction as H atoms play a major role in fuel consumption.…”