Developments of Infrared TV system for heat flux measurements - - PowerPoint PPT Presentation

2014년 2월 25일 Mayhills Resort

Natio ional F l Fusio sion Rese search Inst stit itute Dongcheol Seo, S.H. Hong, J.G. Bak E.N. Bang and KSTAR team

Developments of Infrared TV system for heat flux measurements

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Abstract

Surface temperature and heat flux measurements are very important issues in high power fusion devices to guarantee safe long pulse plasma operation. Many fusion devices are to measure surface temperature of the Plasma Facing Components (PFCs) and heat flux measurements using the infrared camera system. The Infrared TV system has been installed in 2010 in Korea Superconducting Tokamak Advanced Research (KSTAR) to monitor the increase of the temperature of the ICRH antenna, and heat flux to the first wall. The specification of the Infrared camera (FLIR/ThermoVision SC6000) are resolution of 640x512 pixels, full frame rate of 125 FPS and Noise equivalent temperature difference (NETD) of less than 25mK. The spatial resolutions are ~ 5.14 mm/pixel at the poloidal limiter and ~5.47 mm/pixel at the outer divertor with a viewing angle of 58 degree. Due to the wide viewing angle, the temperatures at divertor, poloidal limiter, and passive stabilizer have been measured at once. Time resolution of the system is ~10 msec with an exposure time of 0.35msec.

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Abstract - continue

The surface temperature as well as heat flux on the PFCs were measured and estimated by using equation q = κdT/dn, where κ is thermal conductivity, T is the surface temperature, and n is the index of coordinate normal to the surface (e.g. “z”) with assumption of isotropic single material with no deposition. Heat flux on the surface in L- and H-mode plasmas were obtained, in a range from ~24 kW/m2 up to ~167 kW/m2, which are higher than that measured by thermocouple. In this work, we present details of the Infrared TV system in KSTAR and preliminary measurement results.

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Infrared TV system

Poloidal limiter

Divertor

• r IRTV

TV

IRTV IRVB

Layout of the Heating systems and IR image diagnostics IRTV IRVB

Specification of IR camera

• Model : FLIR SC6000HS
• Resolution : 640x512 pixels
• Full frame rate : 1 Hz ~ 125 Hz
• Spectral rage : 3 - 5 μm
• NETD : <25mK
• Detector type : Indium Antimonide

(InSb)

• Measurement range :

0 °C ~ 1500 °C

• Data resolution : 14 bit

IR camera Lead Soft iron P.E. Protective shield for IR camera

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Configuration of the control system for IRTV diagnostics

Control Hardware composition

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FOV of the IR camera

• 1.3

.3

• 1.8

.8

• 2.3

.3

P.S .S.

IR image and 3D cad image of the Field of View

I.L. L. O.D.

Poloidal limiter

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Data analysis

Fourier’s law 𝑟 = −𝜆 𝜖𝜖 𝜖𝜖 where, 𝑟 is the heat transfer per unit area, 𝜆 is the thermal conductivity and 𝜖 is the temperature. The surface temperature rise 𝛦𝜖 in case the semi-infinite solid is given by 𝛦𝜖 = 1 (𝜌𝜆𝜌𝐷𝑞)1/2 𝑄(𝑢−𝜐)

𝜐1 2

⁄

d𝜐

𝑢

where, 𝐷𝑞 is the specific heat, 𝜆 is the thermal conductivity and 𝜌 is the density of the solid. for constant 𝑄 𝛦𝜖 = 2𝑄 𝑢 𝜌𝜆𝜌𝐷𝑞

1/2

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Temperature Calibration

Model : IR-564/301 Specifications: Temperature Range: 50 – 1200 C Emittance Watts/Cm^2 (Watts): 26.68 (135) Wavelength Range: 0.5 - 99um Emissivity: >0.99 Emitter Size: in (mm) 1" (25.4) Source Type: Cavity Temperature Resolution: 0.1 C Calibration Accuracy: +/- 0.2 C to NIST Standard Stability: Short (Long) Term: +/- 0.1 C (+/- 0.2C) Response Time: 100-1200 <70 Minutes

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Heat flux analysis

#9422 t = 2 2.95s I.L. L. O.D.

Thermogr graph phy Heat f flux ux density

P.S .S. Analysis area for O.D. Heat flux profile for O.D

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Comparison between TC, IR and probe at divertor

Temperature (℃) Profile position

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3 5

Comparison area

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SUMMARY

 Installation of the shielding box for protection of the IR camera from the Neutron, magnetic field.  Investigation of the Heat flux at the poloidal limiter and the out board divertor  Evaluation the profile of the heat flux density on the out board divertor.  Comparison between the IR thermography and the thermal couple measurement in the divertor region.  Improvement of the IR thermography measurement for evaluation of the heat flux at divertor target.  Further work for comparison between IR thermography and probe measurement.

• Summary
• Future work