Exploration of novel fuels for gas turbine applications

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Since non-petroleum fuels are becoming a necessity for gas turbine operators, 2nd generation biofuels are in development and need to be evaluated for wide spread use in the coming years. Combustion in gas turbine combustors is very complex with many strongly coupled variables interacting to prepare the fuel air mixture in limited space with very stringent emission standards. Hence existing design tools to devise a combustor are very specific to properties of fuels in use. Analytical correlations paired with simulations are the design tools used to account for phenomena such as fuel evaporation, mixing and diffusion, the strong turbulent aerodyna- mic flow, the high temperature convective and radiating flow, and the strong chemical reaction with high- energy delivery. Therefore, fuel properties are a critical factor to account for added energy to the flow delivered to the turbine section at high temperature but with a well-defined profile to prevent blade erosion. The most significant challenge in design is to predict for very low emissions that are strongly coupled to reacting tempe- rature. Therefore when a new fuel is used in a gas turbine combustor, all the design tools have to be enhanced to account for changing properties in existing or newly developed gas turbine combustor. The performance and pollutant emissions for biofuelled gas turbine engines can be predicted with better accuracy, using validated combustion models. The objective of this research project is to study the characteristics of novel gas turbine fuels in non-combusting and combusting systems to decouple their interaction with simpler geometries to identify the underlying variables controlling the combustion phenomena and to develop useful correlation models from the experimental or numerical data. For non-combusting systems, fuel sprays will be characteri- zed with advanced laser techniques to study the influence of changing fuel properties on droplet formation and the ultimate size distribution fed to the combustor. For the combustion systems, they will vary from simple laminar and turbulent open burners, to complex swirl generic combustors, approaching realistic industrial combustors. This project will also provide feedback to biofuel producers to tailor their products to end users.