Boundary Layer Separation and Reattachment Detection on Airfoils by Thermal Flow Sensors

Sensors

Hannes Sturm¹  Gerrit Dumstorff¹  Peter Busche²  Dieter Westermann² 

[1] IMSAS (Institute for Microsensors, -actuators and -systems), MCB (Microsystems Center Bremen), University of Bremen, Otto-Hahn-Allee, Bldg. NW1, 28359 Bremen, Germany; E-Mails:;Deutsche Wind Guard Wind Tunnel Services GmbH, Oldenburger Straβe 65, 26316 Varel, Germany; E-Mails:

关键词: boundary layer separation;    flow separation;    stall;    reattachment;    airfoil;    wind tunnel;    thermal flow sensor;    flexible;    polyimide;    thermopile;   

DOI  :  10.3390/s121114292

来源: mdpi

【 摘 要 】

A sensor concept for detection of boundary layer separation (flow separation, stall) and reattachment on airfoils is introduced in this paper. Boundary layer separation and reattachment are phenomena of fluid mechanics showing characteristics of extinction and even inversion of the flow velocity on an overflowed surface. The flow sensor used in this work is able to measure the flow velocity in terms of direction and quantity at the sensor's position and expected to determine those specific flow conditions. Therefore, an array of thermal flow sensors has been integrated (flush-mounted) on an airfoil and placed in a wind tunnel for measurement. Sensor signals have been recorded at different wind speeds and angles of attack for different positions on the airfoil. The sensors used here are based on the change of temperature distribution on a membrane (calorimetric principle). Thermopiles are used as temperature sensors in this approach offering a baseline free sensor signal, which is favorable for measurements at zero flow. Measurement results show clear separation points (zero flow) and even negative flow values (back flow) for all sensor positions. In addition to standard silicon-based flow sensors, a polymer-based flexible approach has been tested showing similar results.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.