One of my main tasks during my PhD studies and my employment as research associate at the University of Karlsruhe (2002-2007) was the design and development of novel fuel injection systems for gas turbines used as jet engines. A highlight of my PhD research at Karlsruhe was the award of a European Patent (06009563.5-, 2006) concerning a fuel injection apparatus I designed and developed jointly with my supervisor and a research colleague, based on the airblast nozzle concept. The special feature of the patented fuel injection apparatus, was the establishment of a lifted swirl flame. The device was designed and developed in terms of the research project “Towards Lean Combustion”. AST4-CT-2005-012326 (FP6) link.
The patented technology relates to a fuel injection apparatus, in particular for aircraft gas turbine engines, comprising a central channel which extends at least between a fuel injection means and an injection opening to a combustion chamber and forms a diffuser at said injection opening, wherein said fuel injection means is adapted to spray liquid fuel across a primary flow of gaseous oxidation medium onto the radially inner surface of a generally annular member downstream of said fuel injection means to form a fuel film flow in a generally downstream direction over said surface, a downstream end of said annular member terminating in an annular lip.
The fuel injection apparatus further comprises swirl generation means applying a swirl to the primary flow of gaseous oxidation medium and means for directing a secondary flow of gaseous oxidation medium, a mass flow of which is equal or higher than a mass flow of the primary flow, over the radially outer surface of said annular member to cooperate with said primary flow to provide atomization of said fuel film downstream of said annular lip.
A mechanical drawing of the patented airblast nozzle is given in the figure below (click to enlarge).
Zarzalis, N.; Fokaides, P.A.; Merkle, K.: Fuel injection apparatus, European Patent: EP 1 722 164 A1, 2006 link