Department of Engineering Master's Defence: Stefán Óli Valdimarsson
Myndvinnsla á sjónrænum hitamælingum í iðustreymi með notkun thermochromic liquid kristalla
Föstudaginn 15. janúar mun Stefán Óli Valdimarsson verja meistararitgerð sína sem ber titilinn Image processing for optical thermal measurements basedon thermochromic liquid crystals in turbulent flow / Myndvinnsla á sjónrænum hitamælingum í iðustreymi með notkun thermochromic liquid kristalla
Dagsetning: 15.janúar, kl:10:00
Stofa: M122
Nemandi: Stefán Óli Valdimarsson
Leiðbeinandi: Ármann Gylfason, dósent, Háskólinn í Reykjavík
Nafn og titill prófdómara: Gylfi Árnason, doktor í verkfræði
Titill: Image processing for optical thermal measurements basedon thermochromic liquid crystals in turbulent flow / Myndvinnsla á sjónrænum hitamælingum í iðustreymi með notkun thermochromic liquid kristalla
Abstract
The main objective of this thesis is to develop an image processing algorithm for optical temperature detection for experimental turbulence research. The detection method takes advantage of the color refraction of thermochromic liquid crystals (TLC), that emit color of different wavelength within the visible spectrum correlated with their temperature when subjected to white light. Images are filtered using the HSV representation of images, and a calibration algorithm associates temperature values to hue (H) values. Using the calibration, an algorithm determines the temperature at various location in the image. Two data sets are used to validate the results, images from a RBC experiment and figures of constructed velocity fields. Temperature of various points in the RBC images are determined using the algorithm. The temperature values correspond with the surrounding fluid color in relations with the calibration images. Temperature field of the imported image is constructed, and it shows temperatures in valid a range and mimic the corresponding images correctly. To further test the algorithm, data obtained from a online data base is used to create velocity field images. The images are then reconstructed using the algorithm, and resulting figures resemble the original figure well, varying between methods. A second objective of the thesis is to design and implement a part of a Rayleigh Bénard flow facility, and calibration facility for the temperature detection systsems. For this part, extensive analysis of various design requrements for such facilities have been done, and finalized designs are presented.
