viper cleansky project valve high performances for flow control separation in aircrafts >> project The VIPER (Valve hIgh PERformances for flow control separation in aircraft) Cleansky project aims at developing, manufacturing and testing piezoelectric-based high speed valves to accurately control the air flow (Active Flow Control Actuators) on transport and business aircrafts. The objective is to delay the separation of the boundary layer in flows over airfoils which results in drag reduction. This Cleansky project is under the SFWA (Smart Fixed Wing Aircraft) ITD (Integrated Technology Demonstrator). The project is coordinated by Cedrat Technologies and performed with the help of Onera DMS, acting as subcontractor and Fraunhofer ENAS, acting as topic manager. Cedrat Technologies (CTEC) & Onera DMS have been working together for over 4 years in a close partnership over highperformance pulsed jets valves based on APA® (Amplified piezoelectric Actuators). The main advantages of using piezoelectric technology for this type of valves lie in the controllability and fast-response time allowed. Fig1: APA® actuator integrating two ECS sensors The targeted performances of the valve (ejection speed and mass flow) are currently world records: • Air exit velocity of 340m/s • Air linear mass flow of 425 g/s/m • Actuation frequency of 500Hz The duration of the VIPER project is 42 months and it started on 1st of November 2012 (ending on 31st of December 2015). Copyright © CEDRAT TECHNOLOGIES | 04/2016 Fig2: APA® CFRP actuator driven by CTEC’s SA75D high power amplifier This customized APA® integrates a CTEC designed Eddy Current Sensor (ECS) for a direct, contactless and extremely precise measurement of the shell deformation (Fig 1). Other technological solutions to reach the highest possible bandwidth include CTEC’s SA75D high power Switching Power CEDRAT TECHNOLOGIES • 59 Chemin du Vieux Chêne • Inovallée • 38246 MEYLAN Cedex France

viper cleansky project Amplifier (dedicated to piezo actuators) completed with signal pre-shaping adapted to fast valve application (Fig 2). As of today, one VIPER fast Active Flow Control valve has been designed and manufactured (Fig 3). It reproduces an 80mm wide wing section (leading edge), with a slit ejecting the pulsed compressed air. Its functionality was tested by CTEC and tests at ONERA DMS are ongoing to assess the achieved pulsed jet performances (speed, mass flow), with complete results expected middle of 2016. Fig3: VIPER valve assembled The reduced weight and the high dynamic capabilities...