Aiaa Optical Sensors

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  • Note: The high school branch has the support of the Central Florida section, the University of Central Florida student branch and several former faculty advisors.
  • Aiaa Optical Sensors

    1. 1. AIAA-2009-5661 Temperature Variation of Optical Sensors Popov and R. Botez, École de Technologie Supérieure, Montréal, Canada; M. Mamou, National Research Council of Canada, Ottawa, Canada; and L. Grigorie, École de Technologie Supérieure, Montréal, Canada AIAA Guidance, Navigation, and Control Conference 10 - 13 Aug 2009 Place, Chicago, Illinois
    2. 2. SUMMARY <ul><li>Project context </li></ul><ul><li>Experimental set-up </li></ul><ul><li>Wind tunnel data post-processing </li></ul><ul><ul><li>Optical sensors reading offset </li></ul></ul><ul><ul><li>Optical sensors reading correction </li></ul></ul><ul><ul><li>Pressure distribution correction results </li></ul></ul><ul><ul><li>Spectral analysis of optical sensors signal </li></ul></ul><ul><li>Conclusion </li></ul>
    3. 3. Project context <ul><li>CRIAQ Project 7.1 </li></ul><ul><li>Laminar Flow Improvement on an Aeroelastic Research Wing </li></ul><ul><li>Partners </li></ul><ul><li>Objectives </li></ul><ul><li>To develop a system for active control of a morphing wing during flight to maintain laminar flow over the upper surface of the wing </li></ul><ul><li>To detect the airflow characteristics using optical sensors installed on the upper surface of a morphing wing </li></ul>
    4. 4. Experimental setup <ul><li>Wing airfoil NACA 4415 </li></ul><ul><li>21 flow cases characterized by </li></ul><ul><ul><li>3 Mach numbers (0.1, 0.15, 0.2) </li></ul></ul><ul><ul><li>7 angles of attack  </li></ul></ul><ul><ul><li>(3 0 , 2 0 , 1 0 , 0 0 , -1 0 ,-2 0 , -3 0 ) </li></ul></ul><ul><li>Sensors used for cross checking: </li></ul><ul><ul><li>9 pressure taps (PT) </li></ul></ul><ul><ul><li>1 Kulite sensor (KU) - microphone </li></ul></ul><ul><ul><ul><li>Sampling frequency 2000 Hz </li></ul></ul></ul><ul><ul><li>4 Optical sensors (OS) </li></ul></ul><ul><ul><ul><li>Range: 0 to 15 psia (absolute pressure reading) </li></ul></ul></ul><ul><ul><ul><li>Resolution: 0.01% full scale (0.0015 psi) </li></ul></ul></ul><ul><ul><ul><li>Sampling rate : 1000 Hz </li></ul></ul></ul>
    5. 5. Experimental setup Optical sensor Kulite sensor Kulite OS 1 OS 2 OS 3 OS 4 Oil film flow visualization
    6. 6. Optical sensors reading offset <ul><li>Offsets between the mean OS and PT pressures values followed a uniform rule variation with Mach and  </li></ul><ul><li>Match between the T static variations during the tests and the offset values. </li></ul><ul><li>OS has a deviation from pressure reading with the T variation of 0.026 – 0.037 psi /deg C. </li></ul>
    7. 7. Optical sensors reading correction Δ T is the difference between the temperature calculated at the sensor location and the temperature of the calibration from the beginning of test 296 K Local mach no. Local temperature Total temperature of air in wind tunnel Pressure correction where and Optical Sensor no. Channel no. Temperature deviation Reading deviation OS1 2 0.037 psi/deg C - 1.11% of mean pressure psi OS2 4, 6 0.030 psi/deg C - 0.65% of mean pressure psi OS3 12, 14 0.037 psi/deg C - 1.02% of mean pressure psi OS4 16, 18 0.026 psi/deg C - 0.62% of mean pressure psi
    8. 8. Pressure distribution correction
    9. 9. Spectral analysis of optical sensors signal Laminar-to-turbulent transition triggered by Tolmien- Schlichting waves f>1kHz Optical sensors blind to detect transition due to sampling rate limitation Other optical sensors tested were temp. compensated f=10 kHz F.S. 15 psia Accuracy 1% (0.15 psi) Resolution 0.1% (0.015 psi) Not sufficient accuracy and resolution Kulite sensors Sampling at 10 kHz Resolution <0.002 psi Mach = 0.275 Tolmien- Schlichting waves PT8 OS4 Mach = 0.2 PT8 OS4 Mach = 0.1
    10. 10. Conclusion <ul><li>It was found that optical sensors can be used for the pressure measurements on the surface of the model, provided that each sensor has a thermocouple installed at the same position. </li></ul><ul><li>These thermocouples should provide the optical sensor static temperatures for an accurate reading of their pressures. A new feature in this paper is the correction of the optical sensors readings using of the static temperature recorded in the airflow upstream of the wind tunnel test section. </li></ul><ul><li>In the absence of thermocouples, the local temperature at the position of each optical sensor was estimated as shown in the paper. By taking into account the various elements that might introduce errors, fairly accurate pressure readings were obtained. </li></ul><ul><li>The turbulent boundary layer investigation demonstrated that optical sensors were found to be a good alternative to the classical present technologies using Kulite sensors, piezo-electric or hot film sensors, provided the acquisition unit of the optical signal to have a minimum sampling rate of 2 - 4 kHz or more and the sensors characteristics 2 - 5 psid FS or 15 psia FS, accuracy less than 0.01 psi and resolution less than 0.001 psi. </li></ul>
    11. 11. Thank you! Questions?

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