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Advanced Design of Very High Power Density Piston Engine and Thermal Management Challenges for Aircraft Application

Periodic Reporting for period 2 - CS2-WP714-DE (Advanced Design of Very High Power Density Piston Engine and Thermal Management Challenges for Aircraft Application)

Reporting period: 2017-08-01 to 2019-06-30

This project deals with the innovative development of the SR460 engine, a new engine derived from the SAE current engine (SR305) and extended up to 6 cylinders. The works will focus on architecture evolutions and new parts designs, providing thus weight reduction, power density improvement and maturity level increase (compared to the demonstrator which had run in 2014). This CS2 program will allow SAE to offer a competitive and environment-friendly alternative to gasoline engines for power up to 400hp.

The main objective of this project is to improve the power density of the engine, by reducing its weight and confirming its power capabilities, based on SAE SR305 4-cylinder engine return of experience.

On the basis of the existing combustion chamber and piston from SR305 engine, Danielson Engineering and DFM Europe will improve the design of the whole engine, taking into account thermo-mechanical loads, weight considerations and up-to-date materials. Furthermore, the engine cooling system will be designed to increase the engine performances and reliability, integrating the specific requirements of an aeronautical application (safety, fire resistance, environment compliance and resistance…).

At the end of the action, 4 prototype enhanced engines are available and reach the objectives defined in terms of power density and reliability.
Concerning DE, the work completed during the second period mainly covers the manufacturing, the assembly and the testing of the SR460 enhanced engine.
The batch sets of prototype parts have been manufactured and inspected before the assembly of the engines.
After an oil pump failure that has been solved, four engines were debugged and then run-in, reaching a maturity and reliability levels in accordance with the commitments made with CS2.
Further, the development of the SR460 enhanced engine could eventually be pursued by SAE, especially by conducting tests on propeller benches, more representative of the actual operating conditions of an aircraft engine.

Concerning DFM, work done first addressed thermal management under-the-wood thermal; the latter was achieved from the DFM-Europe dedicated software DOFI. The latter is based on opensource and provides a new CFD software able to deal with full coupled and massive parallel approach. Heat transfer system has been simulated and efficiency may be still gain to enhance thermal exchange especially in aircraft engine.
The fundamental contribution of DFM is the demonstration of the use of mechanical vibration as a potential source of increased heat transfer. Such source is “free” in aircraft engine and actuators provide vibrations that enhance heat transfer from thermal boundary-layer disruption.
The DFM contribution can be valued on several levels. From a fundamental point of view, the work is quite innovative and can serve as a support for international publications. From a technical point of view, using inherent sources (and therefore free) such as vibration to improve heat transfer is a key that contributes to the improvement of the overall engine performance. And finally, from a financial view point; indeed, the DOFI software edited by DFM-Europe is a complete software validated in a multitude of fields including aeronautics via CSII. It offers a possibility of significant reduction in software costs without altering CFD efficiency
SR460 enhanced engine