Thermographic Analysis of a Fusion Plant

What will the energy supply of the future look like? The Max Planck Institute for Plasma Physics (IPP) in Greifswald is dealing with this question.

In accordance with the weightily initial question, the researchers can draw on an impressive research instrument. “Wendelstein 7-X is the world’s largest stellarator-type nuclear fusion facility,” says Dr. Marcin W. Jakubowski from Stellarator Edge and Divertor Physics Department at IPP. “It is intended to show whether this construction type is suitable as a permanently operated power plant.” The aim is to achieve plasma discharges lasting up to 30 minutes with this plant, in other words, half an hour of continuous operation. This would be an important preliminary work on the way to a form of energy production that does not require fossil fuels such as oil, coal and gas, does not produce CO2 emissions and does not further promote global warming. During the second experimental campaign, which ended in October 2018, discharges lasting up to 100 seconds were achieved. This is considered a world record for a fusion facility of this type.

Use of the High-end ImageIR® 9300 Camera Secures Operation of the Fusion System

The scientists measure temperatures of up to 1,000 °C on the surface of the graphite tiles. In exceptional cases and locally very limited, up to 2,000 °C are registered. “Temperatures of more than 1,200 degrees Celsius are critical,” explains Dr. Marcin W. Jakubowski. “If this happens, the divertor can be damaged and tile elements can come loose.” If this were to happen, the system would have to be stopped and the divertor repaired. The consequence would be a forced break of at least six months.

Introducing the world’s fastest 2D polarisation camera, at over 1 million frames per second!

Key Uses include:

• Analysis and visualisation of internal stress distribution during metal processing
• Evaluation of stress propagation around cracks due to impact fracture
• Dynamic observation of crystal axis/orientation state on liquid crystal/crystal material
• Visualisation of fluid stress distribution generated by viscoelastic body or soft matter

Polarisation can measure and visualise various physical quantities and properties

*All information provided by Photron USA

Real time measurement of strain and deformation can be a valuable asset and is available through Vic-Gauge real time processing. The below is a real case study of how Vic-Gauge was used, as part of a solution generated by Correlated Solutions to measure real time strain.

Key Objectives of DIC Project

• –Measure real-time strains and deformations of flexible sheets
• –Real-time analog output for strain and displacement measurement to control test

Challenges

• For single camera, several key requirements
  • Minimise the out-of-plane movement
  • Maintain nominal planarity of specimen surface
  • Keep sensor plane nominally parallel to specimen surface

Advantages of DIC Measurement System

• Full-field deformations throughout experiment
• Both quasi-static and dynamic loading measurable

Careful positioning and orientation of the DIC camera is crucial for most accurate measurements

• Correct orientation is readily achieved with carpenter’s square or laser pointer and a small mirror attached to specimen holder.

Minimize the error from any out-of-plane specimen movement by increasing distance from camera to the specimen

• Increased lighting intensity necessary for this situation

Key Points

• Test can be controlled using output analog signal from Vic-Gauge
• Large or small deformations are measurable

The AOS high speed camera range has for years been used as part of crash testing around the world. Their newest range of camera offers incredible resolution at high speed meaning that they are able to capture even more detail at a higher frame rate.

The below sequence of videos showcases the range of cameras used in a crash test of a truck, filmed at 80km/h.

Truck hitting congested cars 80km/h filmed with AOS L-Pri @ 2500/fps. Footage provided by AOS Technologies

Truck hitting congested cars 80km/h filmed with AOS M-Pri @ 1200/fps. Footage provided by AOS Technologies

Wide angle of truck hitting congested cars 80km/h filmed with AOS L-Vit @ 1000/fps in full HD. Footage provided by AOS Technologies

IR Camera Range

Active thermography is the induction of a heat flow by energetically exciting a test object. The heat and the flow of energy is then influenced by defects or material layers which makes it a great application for materiel testing. These inhomogeneities can be sen on the surface by high-precision infrared cameras such as our ImageIR and Variocam range.

Our range of cooled IR cameras are perfect for any active thermography application within the engineering, health or automotive industries. The cooled cameras allow for a more accurate temperature measurement at a higher resolution. The range of thermal cameras has geometric resolutions of up to (1,280 x 1,024) IR pixels and thermal resolutions far below 0.015 K. As well as this, there is optional high temperature calibrations allowing the measurement of materials such as metal and others with high heat conductivity

IR Software

The thermography software IRBIS® 3 active analyses the thermo-graphic sequences, which have been generated during the test, and edits them to create a false colour image, in which defects can be marked for further evaluation or documentation. For this purpose, several different analysis procedures are available. The choice of the correct algorithm depends on the material characteristics, geometry and type of defects to be detected.

While the quotient method investigates the heat flow of the test object by reference to the increase and decrease of the surface temperature, the pulse-phase thermography (PPT) relies on the analysis of the temperature profile of different frequencies. For each frequency, two event images are generated, one amplitude- and one phase image. The lock-in thermography (LIT) analyses the sequence of periodic excitation of the test object.

Application of Active Thermography]

Active thermography has a number of applications, however is mainly used in manufacturing and material testing. Some specific applications include:

• Detection of layer structures, delaminations and inserts in plastics
• Detection in CFRPs of the automotive and aerospace industry
• Investigation of interior structures or impacts on honeycomb lightweight constructions
• Recognition of deeper material deficiencies, such as blowholes in plastic parts or ruptured laser welding seams