New tools to model combustion and fuels
The fuel injector is critical to the design of low-emission combustors. By understanding and controlling the complex physics of fuel atomisation, there is great potential for minimising harmful emissions. Until now, simulations have been relying on over-simplistic definitions of the fuel spray. In addition, current soot models are not sufficiently accurate to support the design of new environmentally friendly combustors. The two modelling areas are closely related as the spray characteristics set the boundary conditions for soot modelling. The FIRST (Fuel injector research for sustainable transport) project delivered a step change in detail and accuracy of predicting spray break-up and soot emissions through advanced physics-based modelling techniques, diagnostics measurements and derivation of sophisticated correlations. Development of a virtual injector numerical tool and soot formation predictive techniques requires extensive validation databases with quantitative measurement results. Detailed atomisation and spray experimental measurements were performed using advanced state-of-the-art diagnostics methods across a range of geometries to validate both the physics- and phenomenological-based modelling approaches. For atomisation, researchers investigated three different levels of experimental complexity: fundamental configurations, idealised injector configurations and industrial injector configurations. For soot measurements, several modern measurement techniques were tested and applied to provide comprehensive data sets for soot model validation. Work on numerical models of the atomisation process included small-domain direct numerical simulations of the Navier-Stokes equations, computational fluid dynamic calculations of combustor geometry and phenomenological models. The newly developed spray break-up and soot models were incorporated into project partners' design tools. These tools were then used to predict the spray and emissions performance of state-of-the-art low-emission combustion systems. Through improved measurement and modelling tools both in fuel spray and in soot formation, the FIRST project’s outcomes accelerate development of affordable, cleaner and reliable engine products. These new developments will help the aviation industry move a step closer to achieving the Advisory Council for Aviation Research and Innovation in Europe (ACARE) goals for preserving the environment.
Keywords
Combustion, fuels, engines, aviation, transport, fuel injector, soot
