A FLIR thermal imaging camera is being used by Dassault Aviation to study laminar air flows during the test flights of their airplanes.
Air flowing across an airplane's wings provides the lift essential for flight, but can also cause friction and drag to slow down the aircraft and cause inefficient propulsion. Laminar air flow along an airplane's wings can theoretically greatly reduce drag, improving the airplane's efficiency. Wing designs that stimulate laminar air flow are constantly being studied by aerodynamics researchers.
Dassault Aviation performed test flights with a Falcon 7X using a FLIR Systems thermal imaging camera that can differentiate between laminar flows and turbulent flows, allowing the researchers to evaluate the laminarity of the air flow on a wing during the flight. Dassault used a FLIR SC7750L thermal imaging camera, which is capable of measuring temperature gradients at high altitudes, despite low outside temperatures and pressure.
Part of the 'Smart Fixed Wing Aircraft' effort under the European Clean Sky research program, this test flight is a precursor to planned 'smart laminar wing' flight tests in 2014 on a specially modified Airbus A340-300 by Airbus, Dassault and other partners. One of Europe's largest research initiatives ever, the Clean Sky program aims to develop technologies for cleaner and quieter next-generation aircraft.
A leading aerospace company with presence in over 70 countries across five continents, Dassault Aviation produces the Rafale fighter jets as well as the complete line of Falcon business jets.
According to Philippe Rostand, Future Falcon Programs Project Manager, Dassault has plans to implement drag-reducing laminar flow technology in their designs in the near future. Currently laminar wings are only used on sail planes and small business jets. Demonstrations and analysis on a larger scale are needed to confirm the efficiency increase and the safety of using laminar wings on larger aircrafts.
Philippe explains that the process of a laminar boundary layer becoming turbulent is an extraordinarily complicated process, which at present is not fully understood primarily due to equipment being unable to accurately map the laminar and turbulent areas of a wing. That is where the thermal imaging camera from FLIR systems comes into the equation.
He adds that the use of thermal imaging technology to detect laminar air flow is based on the detection of minute differences in temperature caused by friction. The turbulent areas of the wing, where there is more friction should therefore be warmer than the laminar areas. The extremely small difference in temperature, typically between 0.5°C and 3°C can only be accurately detected by a reliable thermal imaging camera.
Philippe found the answer in the FLIR SC7750L thermal imaging camera. A key objective was for the thermal images to reveal a distinct temperature difference, allowing them to locate the boundary between the laminar and turbulent areas of the wing. The thermal data is still under analysis by Dassault Aviation and ONERA, the French national aerospace research centre, but initial reports indicate that this goal has been achieved.
Philippe concludes that the test with the FLIR SC7750L thermal imaging camera proves thermal imaging technology is an effective tool for laminar wing research. This measurement technique will be used in all future test flights to be flown by Dassault, Airbus and various European partners, with the test results helping them produce better and more energy-efficient airplanes in the near future.
FLIR thermal imaging cameras are available in Australia from FLIR Systems Australia .