Eric Goodger

Aviation fuels technology

This book presents the current specifications for aviation gasolines and turbine fuels, with descriptions of the method of test for each property, and of the main production processes to achieve the specified standards. The possibilities of supplemental fuels derived from alternative sources are discussed. The availability, properties and performance of a range of substitute fuels, together with the energy economy of the production and use of these alternatives are also examined. Topics covered include: current aero engine types; current aviation fuel types; production; specification test methods; operational handling; fuel characteristics within air-craft fuel systems; fuel combustion performance; development of specifications; relaxation of specifications; aviation fuels from alternative sources; aviation fuels substitutes; and fuels for high performance aircraft.

Radiation and Smoke From the Gas Turbine Combustor Using Heavy Fuels

Broadening of aviation fuel specifications has been simulated using blends of gas oil and residual fuel oil. Radiation, smoke and temperature measurements in an experimental combustor at various air pressures, inlet temperatures and air/fuel ratios showed a diminishing rate of increase of radiation with soot concentration, and reduced sensitivity of smoke to fuel hydrogen content at higher combustor pressures. 6 refs.

Heavy-fuel flame radiation in gas turbine combustors-exploratory results

Abstract With lower costs and greater availability, heavy fuel oil appears as an attractive alternative to the conventional gas oil used in industrial gas turbines. However, higher levels of radiation and smoke are expected, and this note reports on some preliminary tests made with a combustion chamber burning fuels of different carbon content, ranging from kerosine to a 25% blend of residual fuel oil in gas oil, at a chamber pressure of 10 atm ∗ . The combustion rig was equipped with a total-radiation pyrometer and black-body furnace capable of measurement at different axial stations along the spray-stabilized flame. The presence of the residual fuel oil in the gas oil was found to promote significant increases in the mean levels of radiation, emissivity and smoke density, with a modest increase in liner temperature.

ASSESSMENT OF LIFE CYCLE EMISSIONS OF BIO-SPKS FOR JET ENGINES

Bio-Synthetic Paraffinic Kerosene (Bio-SPK) is one of the most anticipated renewable energy to conventional Jet kerosene (CJK). Bio-SPK is plant lipid which is thermo-chemically converted to kerosene like compositions to serve as “Drop-in” biojet fuel. The environmental impact of Bio-SPK is to be understood to determine its potential as a carbon neutral / negative fuel. Assessment of Life Cycle Emissions of Bio-SPKs (ALCEmB) aims to deliver a quantitative, life cycle centered emissions (LCE) model, reporting the process related-carbon footprint of Bio-SPKs. This study also encompasses the key emission-suppressing feature associated with biofuels, termed as “Biomass Credit”. The Bio-SPKs chosen for this analysis and ranked based on their “Well-to-Wake” emissions are Camelina SPK, Microalgae SPK and Jatropha SPK. The Greenhouse gases (GHGs) emitted at each stage of their life cycles have been represented in the form of CO2 equivalents and the LCE of each of the Bio-SPKs were weighed against that of a reference fuel, the CJK. Camelina SPK among the three Bio-SPKs analyzed, was determined to have a relatively lower carbon footprint with a <70% carbon reduction relative to CJK followed by Jatropha SPK and Microalgae SPK respectively. In general, Bio-SPKs were able to reduce their overall LCE by 60–70%, at baseline scenario, relative to its fossil derived counterpart.Copyright

Prandtl—Meyer Expansion

This table of Prandtl—Meyer Angle as a function of Mach Number is calculated from the single equation:

Plane Shock Wave

{\rm{Prandtl - Meyer}}\;{\rm{Angle = }}\sqrt {\left( {{{\gamma + 1} \over {\gamma - 1}}} \right)} {\tan ^{ - 1}}\sqrt {\left\{ {{{\gamma - 1} \over {\gamma + 1}}({M^2} - 1)} \right\}} {\tan ^{ - 1}}\sqrt {({M^2} - 1)} ({\rm{radians}})

Current Aviation Fuel Types

(6.1) (see above diagram)

Development of Specifications

A significant problem encountered in the gas turbine industry with fuel products is the degradation of fuel and fuel systems by microorganisms, which are largely bacteria, embedded in biofilms. These microorganisms cause system fouling and other degradatory effects, extending often to sudden failure of components with cost implications. Current methods of assessment are only post-impact evaluation and do not necessarily quantify the effects of fuel degradation on engine performance and emission. Therefore, effective models that allow predictive condition monitoring are required for engine’s fuel system reliability, especially with readily biodegradable biofuels. The aim of this paper is to introduce the concept of bio-fouling in gas turbines and the development of a bio-mathematical model with potentials to predict the extent and assess the effects of microbial growth in fuel systems. The tool takes into account mass balance stoichiometry equations of major biological processes in fuel bio-fouling. Further development, optimization and integration with existing Cranfield in-house simulation tools will be carried out to assess the overall engine performance and emission characteristics. This new tool is important for engineering design decision, optimization processes and analysis of microbial fuel degradation in gas turbine fuels and fuel systems.© 2013 ASME