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Valves for OiL regulaTion with High AccuracY and REliability

Periodic Reporting for period 2 - VOLTAYRE (Valves for OiL regulaTion with High AccuracY and REliability)

Reporting period: 2020-06-01 to 2022-03-31

The VOLTAYRE project responds to a new feature needed for future engines with very high dilution rates such as the Ultra High Bypass Ratio being developed by Safran Aircraft Engines. To reduce kerosene consumption, the engine input blower will run at a different speed than the main rotor, allowing on the one hand to increase the secondary air flow provided by the blower and on the other to improve the efficiency of the different compression stages. The blower and compressors work at their best performance point regardless of the flight phase. For both mobiles to rotate at a different speed it is necessary to place an epicycloidal train between the blower and the rotor.
Depending on the flight phase, the UHBR calculator requires the VOLTAYRE servo-valve to adjust the lubrication flows sent to the engine, the epiccycloidal train and the tank.

The objectives of VOLTAYRE is to design & manufacture an innovative high flow direct drive oil valve, and qualify this valve up to TRL 5 level. This valve is able to meter accurately and split the flows coming from the pump to the gearbox and to the engine, whereas the extra flow return to the tank. Our product is also communicating to the FADEC an image of the delivered flows to close the loop and to accurate metering.

VOLTAYRE proposal is based on the upsizing of our patented FACT electronic free low energy limited angle torque motor that requires at least two extra patents. This torque motor is able to provide high torque, high displacement, high ageing stability, without dynamic seals which is able to direct drive a spool that is metering and split an oil flow of about 13000l/h@ 70 bar (57GPM@1000psi). This Valve is coupled with an hydromechanic three-way delta pressure regulator mounted together with the others units on a aluminium manifold.
The Voltayre project started with the kick-off meeting with the topic manager on March 1st, 2019. The reception of the first specification version initiated the specification analysis work. We were then able to work on different equipment architectures that were able to meet the need. Finally, the architecture chosen is not the one proposed in Appendix 1 but another one that allows to integrate a Safran patent on the distribution of oil flows between the engine and the RGB. An additional bypass function has been added in case of valve blockage which also allows the engine to supply oil in cold conditions.
Once the architecture was selected, we worked on the design and preliminary sizing of the equipment. This resulted in a first version representing a 1D model under Amesim to validate the functional part of the equipment and by a digital CAD model to validate the integration on the engine. This digital CAD model has been available as a physical model in 3D polymer printing. The PDR milestone was successfully passed in September 2019.
In the critical design phase, we were able to refine the design and modelling of the equipment. We have been working on the accuracy of the ∆P-sensor to ensure the best possible accuracy. We the sizing of the valve for different condition of operation of the duty cycle. We also worked to determine the cases of failures and the response of the equipment to these failures. We deliver a new version of the more accurate 1D model as well as a more advanced 3D CAD model with a digital validation of its subassembly. The CDR milestone was succesfully passed in July 2020.
In the detailed design phase, we finalise the definition of the valve. We made complementary robustnes computation such as vibration resistance or additional CFD calculations for the differential flow meter in unsteady condition. Then we made all the detail plans of the equipment. We also carried out the assembly tools, the assembly operating documentation. We have launched the realization of the different components of the test bench. The DDR Milestone was succesfully passed in december 2020.
In the equipment assembly phase, we have launched the supply of demonstrator parts, as well as assembly and testing tools parts. We carried out the final assembly and programming of the bench. We have written the various test procedures necessary for the qualification of the equipment for its passage into TRL5.
Once the parts of the demonstrator were received, we were able to assemble the first demonstrator and make a first phase of development of the demonstrator and the of test bench.
The phase concluded with a TRR in April 2021 and a RAU in October 2022 which validated the test procedures, installations, and equipment development.

In the qualification phase, in first time, we continued development test on demonstrator. The results obtained on all the tests are good and have made it possible to validate the proper functioning of the equipment under different conditions of flow, pressure, and temperature. Only the vibration test failed to achieve trl5 level for the equipment.
FACT and Safran Aircraft Engines teams decided to extend the analyses and use all the test results to improve the equipment in order to obtain the TRL5.
The objective of the project is to develop a 4-ways servo-vanne with a more electric architecture, without hydraulically amplified control (servovalve). This architecture allows a functioning in spite of the very viscous oil in cold weather but also a reduction of the risk of external leakage thanks to a reduction in the number of waterproofing.
Our servo-valve will also be electronically free to operate with hot oil in a warm environment without reliability degradation.
It will more accurately enslave the dosed flows by directly measuring depressogenous flow per flow meter, instead of an indirect measure of position.

The developed OFCV through Voltayre project allows meet some of Clean-Sky high level goals regarding the environment the competitiveness and the mobility. For instance, the new generation of aircraft engines, where the OFCV will be used, aim to reduce fuel consumption and CO2 emissions by more than 20% compared to current engines. In addition, the development of this product and the industrial capabilities of FACT, will provide to the European industry an innovative and competitive new solution, and will develop industrial employment within its economic space. Regarding the mobility, reducing CO2 will allow a less restricted air mobility while respecting the environment.
Finally, the experience acquired during Voltayre project has enabled FACT to respond numerous industrial offers. All exploitation activities during reporting period are presented in detail in § 2.
The direct impact of the project on FACT activities are : recruitment of 3 employes and the start of two Ph D thesis concerning electrical part & hydraulic part of our torque motor

Due to Voltayre impact we have increase our request for quotation during the project. Our Direct Drive Valve technology and the first results on size M torque moteur through Voltayre project interested a large number of customers: French, European and also American. We were able to offer our equipment for several types of aircraft system, fuel, oil, air, hydrogen. We won several contract with different customers in order to develop valve or servo actuator base on our torque motor technology.

We have also interested other sectors, particularly around fuel cell applications for aeronautic and heavy transport.
First draft picture of the equipment PDR level
Final demonstrator on table
Final demosntrator on table
Picture of the equipment at DDR level
First 3D printing Mock-up of Voltayre (PDR level)