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Helicopter Engine Air Intake OPtimization Tool

Periodic Reporting for period 2 - HElAIrcOPT (Helicopter Engine Air Intake OPtimization Tool)

Période du rapport: 2017-07-04 au 2018-07-03

The objective of this topic is to set up an industrial and fully automatic optimal design tool, integrating software identified by the Topic Leader, in order to reach TRL6 at the end of the project. This tool has to be dedicated to rotorcraft engine air intake analysis and able to handle multi-objective, multi-parameters and multi-points optimization on a given CATIA CAD.
An effective aerodynamic design of the engine air intakes is essential for ensuring a proper air supply to the first stage compressor and thus an efficient behavior of the whole engine installation. However, its optimization has to deal with a lot of requirements and constraints, not always linked to the engine performance itself, but often aiming at improving conflicting criterions. For instance, the engine air intakes design will have some impact as regards the three following different issues:
• Volume specifications
• Helicopter manufacturer specifications, along with the airframe performance level required
• Engine manufacturer specifications, along with the engine performance level required
In order to achieve the task, optimization will take into account 2 flight conditions. Among all optimization strategy available, due to CFD solver limited capabilities for adjoint computations, a Surrogate Based Optimization approach is proposed. It allows use of gradient free and global optimization method.
Two optimizations are planned during the task: one without intake grid and a last with it. The final objective is to improve flow solution at Air Intake Plane from a distorsion and pressure losses aspect.

Objective per WP
The WP1 includes of Project Management & Dissemination. Project Management has ended and Dissemination/Exploitation will continue after the end of the project.
WP2's objective was to develop the workflow tool and validate it on sample cases.
WP3 consisted in parameterizing the CAD geometry, study the sensitivity of the parameters, do a design of experiment and start an optimization process to validate the functioning.
WP4 consisted in exchanging data with Topic Manager and installating the process.
For WP5, Filter modelling is done, behaviour of the filter has been understood and results are very good.
During WP6 DOE and optimization has been fully performed.
From the beginning of the project to the end of the period covered by the report the project has released several deliverables.
A first version of the automated process has been created (WP2) and works well with the industrial case (WP3).
Considering physical aspects, study of various phenomena linked to Helicopter's working point has been done (WP3). Geometrical parameters has been added to CAD, their influence on the optimization objectives has been assessed in a sensitivity study (WP3).
The Design of Experiment and optimization without the grid has been done (WP3).
Data have been exchanged with Topic Manager to ensure installation on their facilities (WP4).
Behaviour of the filter has been understood and results are very good (WP5).
Integration on the helicopter is successful (WP5/WP6) and Design of Experiment and optimization with filter show good results (WP6).

Regarding dissemination/exploitaiton, project team attended several conferences and published/is publishing 2 conference papers. Communication has been done throughout the project. The exploitation of the results is shared between coordinator and topic manager, TM will use the process on next Helicopters design and Coordinator will re-use workflow manager to run optimization on other domains (automotive, naval). More details are available in the Communication/Dissemination/Exploitation reports.
As part of “Low Impact, Fast & Efficient RotorCraft (LifeRCraft)” demonstration program, the design of next generation of rotorcraft engine air intakes must assess the global goal of decreasing the pollution generated by helicopters. Indeed, ambitious NOx reduction targets of 80% are set for 2020. The optimization of engine air intake design considering the distortion and pressure loss would permit to gain on the engine operating overall regime. Thus, an engine with an optimized air intake would decrease its fuel consumption and thus less pollute.
The use of optimization workflow during the design step permits to decrease its cost, considering both money and time. Indeed, it decreases the number of manual loops which are time consuming and it improves the efficiency of designers by helping them investigating the effect of several parameters at the same time.
The optimization of engine air intake permits to improve noise emissions by reducing the engine overall regime and the acoustic phenomenon at the intake. The optimization workflow is not considering aeroacoustics phenomenon but an adaptation of the CFD step and add of a dedicated objective function would permit to address this new requirement.