The FLIR SC655 thermal imaging camera is being used at the University of Manchester to help test components’ ability to withstand airflows at high velocities in hypersonic aerodynamic applications.
For the purpose of space exploration and aircraft technologies, researchers have explored travelling at hypersonic speeds, which entails attaining speeds over Mach 5, more than five times the speed of sound, placing a huge strain on the aerodynamic and thermal designs of vessels and components.
The University of Manchester in the United Kingdom has combined their hypersonic wind tunnel with a thermal imaging camera from FLIR Systems to test the capability of components in such conditions. The wind tunnel at the University of Manchester is one of the few experimental facilities in Europe that can reach Mach numbers higher than 5.
Travelling at Mach 6, which roughly translates to a speed of over 4000kmh, massive airflows would rush past the vessel’s surface, causing friction-induced heat, prolonged exposure to which can be detrimental to the structural integrity of the material. Prof Konstantinos Kontis, head of the Aerospace Research Group at the University of Manchester explains that it is therefore very important to test components and designs extensively before they are employed in the field.
The hypersonic flow wind tunnel at the University allows models and components to be subjected to airflows similar to what they will experience in the field. The hot spots on the surface of the test object caused by the friction can be mapped with a thermal imaging camera, enabling the researchers to make recommendations to their clients for design improvements.
A FLIR SC655 thermal imaging camera is being used for the application at the University. According to Kontis, they chose this camera model because it is capable of recording thermal maps of the entire surface of the test object. The camera’s excellent thermal sensitivity allows them to record tiny temperature differences, which added to the external triggering options and high speed video capturing capabilities makes it the perfect tool for the testing application.
Key features of FLIR SC655 thermal imaging cameras:
- Contains an uncooled microbolometer detector that produces thermal images at a resolution of 640 × 480 pixels and a thermal sensitivity of 50 mK (0.05°C)
- Full resolution can be captured at a frame rate of 50 fps
- Provides high-speed windowing modes that allow the operator to increase the frame rate to 200 fps with a resolution of 640×120 pixels
- Fully compliant with both GenICam and GigE Vision protocols
- Relatively easy to integrate with a variety of third-party analysis software packages
Kontis and research associate Dr Erinc Erdem use FLIR ResearchIR software to capture the thermal footage and perform initial analysis of the temperature data. According to Erdem, the software package is very easy to use and provides a lot of options for the researcher including data capture, defining special regions of interest and exporting the temperature measurement strings to third party software for in-depth data analysis.
Wind tunnel airflow
The wind tunnel consists of a pressure chamber on one end capable of pressurising air up to a pressure of 15 bar or 15 times the regular atmospheric air pressure, and a vacuum tank at the other end, which is brought to 1 mbar, one thousandth of the regular atmospheric air pressure. The test object is placed in a test chamber between the two chambers. The pressurised air travels from the pressure chamber into the vacuum chamber, passing the test object en route at a speed of about 4000kmh, similar to travelling at Mach 6.
The FLIR SC655 thermal imaging camera located on top of the test chamber, looking in through a Germanium window accurately maps the thermal hot spots caused by air friction, without being subjected to the force of high velocity airflows.
The knowledge gained by these wind tunnel tests will help enhance designs for high speed aircrafts and re-entry space vessels that need to be capable of bringing payloads to orbit and returning to the Earth’s surface more or less intact. Kontis concludes that the thermal imaging camera is a crucial tool for these developments, which will lead to a better version of crafts such as the Boeing X-5 and the NASA X-43.
FLIR thermal imaging cameras are available in Australia from FLIR Systems Australia .