Propulsion system intake design and unsteady aerodynamics

The UK government Jet Zero strategy has an aim of achieving net zero emissions by 2050. It is expected that this net zero target will be achieved through a mix of different technologies. Even within the wider context of potential changes in aircraft fuel or energy sources, it is acknowledged that advances in aerodynamic research and technologies, for both aircraft and propulsion systems, will be important areas for UK industry as part of the route to reduce the climate impact of aviation. It is known that propulsion integration is a vital aspect in the development of future aircraft for both conventional and novel architectures.

Within that context, the aerodynamic design of the coupled intake/propulsor systems is a key enabling technology. The optimisation of compact intake systems is a route to reducing drag, weight and overall fuel burn and thereby contributing to the net zero targets. For an aero-engine intake and fan system, the off-design conditions such as crosswind take-off and high incidence are the crucial operating conditions. These are the challenging parts for the intake design as there can be a notable impact on the fan performance and operability. The heart of the aerodynamic challenge is centred on the intake flow separation and the resultant flow distortion that is ingested by the fan. This is particularly difficult as it encompasses a wide range of complex flow phenomena and unsteady interactions.

Within the context of the state of the art for intake design, these flow features are not well understood and are acknowledged as posing considerable challenges to the industry design tools. The overall aim of this project is to explore the aerodynamic design of intake/fan configurations with a focus on the design of compact intakes that can potentially deliver drag and weight benefits, while still ensuring aerodynamic compatibility with the fan system. The research will focus on the crosswind design condition. The aerodynamic coupling between the fan and the intake is expected to play a key role and is not well understood. The objectives of the research include the validation of the computational tools for an intake under crosswind conditions, development of novel approaches to characterise unsteady flow distortion, assessment of the sensitivity of the unsteady intake flow-field to intake design parameters, exploration of the novel compact intake design space and ultimately the development of design guidelines for compact intakes.

The methodology will centre on the use of computational methods to predict the unsteady flow field for the intake and rotating fan configuration. The intake design method will use an existing tool that can define and control the intake aerodynamic surfaces. The methodology will also explore both temporal and frequency domain approaches to evaluate the unsteady flow fields.