Forschungs- & Entwicklungsinformationsdienst der Gemeinschaft - CORDIS

FP7

VIAFUMA Berichtzusammenfassung

Project ID: 632539
Gefördert unter: FP7-JTI
Land: United Kingdom

Periodic Report Summary 1 - VIAFUMA (VIbration Analysis methodology for FUel Manifolds of lean burn engines)

Project Context and Objectives:
The development of the lean burn engine is a significant step for the European aircraft engine industry to ensure a continuous reduction in fuel consumption and operational cost and stay competitive in an expanding global market. One of the fundamental design features of lean burn combustion is the use of staged combustion technology where a lean burning main zone and rich burning pilot are used to create lower pollutant emissions without compromise to system operability. Amongst other things this creates the need for a more complex fuel delivery pipework system to control the fuel distribution to the different combustion zones, leading to increased complexity, space constraint and an increased requirement for mechanical integrity to avoid reliability reduction. The lean burn programme under Clean Sky – Sage 6 has made significant contributions towards a flying demonstrator, but one major problem that must be addressed to make the lean burn system a reality is the correct prediction of the vibration behaviour of the fuel manifold system. A higher risk of rumble in the engine, and a larger amount of pipes for the staged fuel delivery increase the risk of HCF in such a system, and without a detailed analysis the failure risk of the engine may be too high.
The accurate prediction of the dynamic response of a fuel manifold assembly is a challenging task, since it consists of a wide range of components, including straight and bend pipes, different types of mounts, clips that hold the pipes in place, inserts to connect the pipe work, and sometimes damping devices to reduce the vibration response of the pipe work. Modelling each component in itself is already quite complicated, but once the system is assembled and filled with fuel, additional features will be present that are expected to have significant impact on the dynamic response. The assembly of the components adds a large amount of joints to the system, introducing potential slip in the contact areas and a resulting nonlinear dynamic behaviour. During assembly misalignments can be introduced into the system which in turn will lead to the introduction of pre-stress that can affect the dynamic response. Additional pre-stresses can be introduced by the pressurised fuel inside the pipes that in addition adds mass to the system which must be considered for a reliable prediction of the dynamic response. The flexibility of the supporting casing structure will influence the dynamic response of the pipework due to coupling effects, and it must be well understood to ensure the correct forcing of the fuel manifold system during the predictions.
The general objective of VIAFUMA is the development of a new and fully validated approach to predict the dynamic response of a lean burn fuel manifold system. Exploiting basic and detailed linear and nonlinear dynamic modelling approaches will allow feasibility studies of the design during the early development and enable detailed analysis during the later design stages.

Project Results:
The progress in the first reporting period has focused on the basic component assembly. A review of the state of the art in pipe modelling was followed by an experimental study on the dynamic behaviour of fuel manifold components, such as pipes, clips, and brackets, and the explicit modelling of the components and their basic assembly. The experimental results showed a major nonlinear dynamic response in the pipe work, with frequency shifts of up to 10% and significant amplitude dependent damping. The need for an accurate nonlinear dynamic analysis was identified, for which a new nonlinear meshing approach for cylindrical structures was developed. It was shown, that geometric nonlinearities only play a minor role in the system response, whereas the rubber and friction of the clip has the largest impact on the response.
Potential Impact:
Given the current state of the art to analyse the fuel manifold system of an aircraft engine a new design strategy will be introduced, allowing the development of robust pipe work systems for the lean burn engine. The suggested approach will introduce truly predictive capabilities to the fuel manifold design, taking the linear and nonlinear dynamic response of the system into account. The suggested strategy will encompass the entire design process, starting from the early design stages, where newly developed basic and fast nonlinear tools (low fidelity models) will allow a fast feasibility study of different design suggestions and the selection of the most promising design.

The development of the lean burn engine is a significant step for the European aircraft engine industry to ensure a continuous reduction in fuel consumption and operational cost and stay competitive in an expanding global market. The lean burn program under Clean Sky – Sage 6 has made significant contributions towards a flying demonstrator, but one major problem that must be addressed to make the lean burn system a reality is the correct prediction of the vibration behaviour of the fuel manifold system. A higher risk of rumble in the engine, and a larger amount of pipes for the staged fuel delivery increase the risk of HCF in such a system, and without a detailed analysis the failure risk of the engine may be too high. VIAFUMA will introduce a change in the capabilities of the fuel manifold vibration analysis, by providing truly predictive methods and tools to model the linear and nonlinear dynamic response of the pipework during the early and detailed design stages. This will allow the optimisation of the fuel manifold system during the development program of the engine thereby minimising the need for engine test data, reducing wear in the components, extending the fatigue life, and lowering the risk of failure of the system. The capabilities provided by VIAFUMA can be seen as an important step towards the realisation of the low burn engine, since they allow the management of the HCF risk of the system which has been identified as a major problem for the lean burn program.

Kontakt

Shaun Power, (Research Services Manager)
Tel.: +44 207 594 8773
Fax: +44 207 594 8609
E-Mail-Adresse
Datensatznummer: 182578 / Zuletzt geändert am: 2016-05-19
Informationsquelle: SESAM