Air flowing across an airplanes wings provides the necessary lift for flight, but the airflow also causes drag and friction, resulting the aircraft slowing down and causing to inefficient propulsion. <\/p>\n
Theoretically, laminar air flow along an airplanes wings reduces drag and improves the airplanes efficiency. <\/p>\n
Therefore, many aerodynamics researchers are looking at wing designs that stimulate laminar air flow. Accordingly, test flights were performed by Dassault Aviation on a Falcon 7X using a FLIR Systems thermal imaging camera. The camera can distinguish laminar flows from turbulent flows, which allows researchers to evaluate the laminarity of the air flow on an airplanes wing during the flight. <\/p>\n<\/p>\n
The highly sensitive FLIR SC7750L thermal imaging camera. <\/p>\n<\/p>\n
The FLIR SC7750L thermal imaging camera was mounted in the top of the tail of the Falcon 7X, looking down on the right horizontal stabilizer. <\/p>\n
The camera employed by Dassault during the test flight was a FLIR SC7750L thermal imaging camera. This sophisticated thermal imaging camera can measure temperature gradients at high altitudes, despite the low outside temperature and pressure. <\/p>\n
In the test at the company's flight test center in Istres, France, Dassault applied a black covering to the right horizontal stabilizer of a Falcon 7X. The FLIR SC7750L thermal imaging camera was mounted to look down on the surface from the top of the horizontal tail. <\/p>\n<\/p>\n
Thermal image of the air flow along the right horizontal stabilizer. <\/p>\n
The test flight was a part of the Smart Fixed Wing Aircraft effort carried out under the European Clean Sky research program, and was a precursor to planned smart laminar wing flight tests in 2014 on a specially modified Airbus A340-300 by Airbus, Dassault, and other partners. <\/p>\n
As one of Europes largest research initiatives ever, the purpose of the Clean Sky program is to develop technologies for cleaner and quieter next-generation aircrafts, which will enter service after 2020. <\/p>\n
Dassault Aviation, one of the leading aerospace companies, has a presence in more than 70 countries spread over five continents. The company produces the complete line of Falcon business jets and the Rafale fighter jet. <\/p>\n
It has assembly and production facilities in France and the United States, and service units in many continents. From the first Falcon 20 made in 1963, Dassault has delivered 2,000 Falcon jets to 67 countries across the world. <\/p>\n
Philippe Rostand, Future Falcon Programs Project Manager, says his company is planning to apply drag-reducing laminar flow technology in its designs in the near future. <\/p>\n
Theoretically the potential of laminar wings is huge. Among other aerodynamic innovations, laminar wing technology offers the largest potential for a dramatic decrease in drag. <\/p>\n
Initial studies indicate a potential 5-10% drag decrease and corresponding reduction in fuel burn and CO2 emissions with a laminar wing design on a large aircraft. The flow of air around an airplanes wing causes friction. This air flow can be laminar, which basically means that no turbulence occurs and the amount of friction is low, or it can be turbulent, which is characterized with larger amounts of friction. <\/p>\n
A larger amount of friction causes significantly higher energy consumption for aircraft propulsion, so aircraft designers want to increase the amount of laminar air flow and decrease the amount of turbulent air flow. <\/p>\n
Philippe Rostand, Project Manager, Future Falcon Programs <\/p>\n
During the period of 1986-1989, Dassault Aviation conducted several successful test flights with an experimental laminar airfoil on a modified Falcon 50. However, at present, laminar wings are only used on small business jets and sail planes. In order to confirm the increase in efficiency and the safe usage of laminar wings on larger aircrafts, demonstrations and analysis are required on a larger scale. <\/p>\n
The process of a laminar boundary layer becoming turbulent is known as boundary layer transition. This is an extraordinarily complicated process which at present is not fully understood. <\/p>\n
One of the reasons for this is the lack in equipment that can accurately map the laminar and turbulent areas of a wing. That is where the thermal imaging camera from FLIR systems comes into the equation. The use of thermal imaging technology to detect laminar air flow is based on the detection of minute differences in temperature. <\/p>\n
The relation between air friction and temperature is well established in scientific literature; an increase in friction will lead to an increase in temperature. The turbulent areas of the wing, where there is more friction, should therefore be warmer than the laminar areas. But this difference in temperature is extremely small, typically between 0.5 and 3 C. That is why we needed a reliable thermal imaging camera that can accurately detect such small differences in temperature. <\/p>\n
Philippe Rostand, Project Manager, Future Falcon Programs <\/p>\n<\/p>\n
Schematic illustration of the distribution of laminar and turbulent flow patterns in the boundary air flow around an airplane wing. <\/p>\n
Philippe found the answer in the FLIR SC7750L thermal imaging camera. <\/p>\n
We hoped that after careful analysis of the thermal data the resulting thermal images would show a distinct temperature difference, allowing us to locate the boundary between the laminar and turbulent areas of the wing. The results are still under analysis by Dassault Aviation and ONERA, (the French national aerospace research center), but initial reports indicate that this goal has been achieved. <\/p>\n
Philippe Rostand, Project Manager, Future Falcon Programs <\/p>\n
At high altitudes, a laminarity of up to 40% was estimated on the upper surface of the horizontal tail, though the Falcon 7X does not have wings particularly designed for laminar air flow. The measurements using the FLIR SC7750L thermal imaging camera were performed to provide experimental validation of this prediction, says Philippe. The initial results seem to suggest that the thermal images show the expected laminarity percentage. <\/p>\n<\/p>\n
Schematic of the Falcon 7X with the FLIR SC7750L thermal imaging camera mounted in the top of the tail, looking down on the right horizontal stabilizer. <\/p>\n
The key features of the FLIR SC7750L thermal imaging camera include: <\/p>\n
This test with the FLIR SC7750L thermal imaging camera has proved that thermal imaging technology is an effective tool for laminar wing research. This measurement technique will therefore be used in future test flights to be flown by Dassault, Airbus and the other European partners on an even larger scale, such as the smart laminar wing that will be flight tested in 2014 on a modified Airbus A340-300 test aircraft. Implementing what we will learn from these tests we will hopefully be able to produce better and more energy efficient airplanes in the near future. <\/p>\n
Philippe Rostand, Project Manager, Future Falcon Programs <\/p>\n<\/p>\n
This information has been sourced, reviewed and adapted from materials provided by FLIR Systems. <\/p>\n
For more information on this source, please visit FLIR Systems. <\/p>\n
<\/p>\n
Original post:<\/p>\n
Aerospace Engineering Using Thermal Imaging to Assess Laminar Designs - AZoM<\/a><\/p>\n","protected":false},"excerpt":{"rendered":" Air flowing across an airplanes wings provides the necessary lift for flight, but the airflow also causes drag and friction, resulting the aircraft slowing down and causing to inefficient propulsion. Theoretically, laminar air flow along an airplanes wings reduces drag and improves the airplanes efficiency. Continue reading