Title :
Fiber Bragg Grating-Based Temperature Distribution Evaluation of Multilayer Insulations Between 300 K–77 K
Author :
Ramalingam, Rajini Kumar ; Neumann, Holger
Author_Institution :
Inst. for Tech. Phys., Karlsruher Insti tute for Technol., Karlsruhe, Germany
fDate :
4/1/2011 12:00:00 AM
Abstract :
An optical method for the evaluation of temperature distribution of multilayer insulation (MLI) is presented. Four fiber arrays with four Fiber Bragg Grating (FBG) sensors in each array are fabricated in a wavelength division-multiplexing (WDM) scheme. MLI temperature varies the gratings periods of the FBG sensors which changes the back reflected Bragg wave length. This can be correlated with temperature change. Because of the small size of theses sensors with a diameter of around Ø 125 μm this kind of temperature measurement is very well qualified to investigate the temperature distribution in a multilayer blanket. For demonstration, a calorimeter with a test cylinder (Ø 219 mm · H 1820 mm) insulated with aluminized Mylar (20 layers) is used. The axial and transverse temperature distribution of MLI is recorded for various vacuum levels and compared with calculated temperature values. The results obtained were well agreed with the theoretical calculations.
Keywords :
Bragg gratings; calorimeters; cryogenics; fibre optic sensors; temperature distribution; temperature measurement; thermal insulation; wavelength division multiplexing; back reflected Bragg wavelength; fiber Bragg grating sensors; fiber arrays; multilayer blanket; multilayer insulations; temperature 77 K to 300 K; temperature distribution evaluation; temperature measurement; wavelength division multiplexing; Cryogenics; fiber Bragg gratings (FBGs); heat flux; multilayer insulations (MLIs); optical detectors; temperature measurements; wavelength division multiplexing (WDM);
Journal_Title :
Sensors Journal, IEEE
DOI :
10.1109/JSEN.2010.2078496
