NASA Fuel Combustion Test Images Acquired by Mikrotron CoaXPress Camera

Summary

Sept. 22, 2023 - The NASA (National Aeronautics and Space Administration) Scientific and Technical Information Program recently developed an apparatus for High-Pressure, Trans-Critical (HPTC) liquid droplet combustion experiments that will allow NASA researchers to study the auto-ignition of different fuel types under a range of ambient conditions. While conducting tests, researchers can modify the environment's pressure, temperature and oxygen content. 

HPTC experiments are carried out inside a pressure vessel machined from a single billet of aluminum. Video imaging systems capture the droplet's ignition and burning, while a data collecting system simultaneously measures temperature and pressure. Typically, each test lasts ten seconds for a single fuel droplet measuring approximately 1mm in diameter.

Two cameras are positioned orthogonally outside the upper portion of the chamber to capture combustion events. To acquire the droplet as a shadowgraph, a Mikrotron MC4082 four-megapixel monochrome camera is set at a frame rate of 1,000 frames per second (fps) with a resolution of 960×960 pixels. The MC4082 is a member of the Mikrotron EoSens 4CXP camera family. Gain, exposure and black level are fixed throughout the test at 80 dB, 570 μs, and 0, respectively. An LED backlight illuminates the tests at a wavelength of 525 nm. The backlight is synchronized to the Mikrotron camera by a controller, which sets the LED power level and pulse duration. The Mikrotron camera has a telecentric lens with an f/16 aperture and a 525-nm bandpass filter. Flames are captured at 180 fps by a USB3 HD color video camera. The resolution for the flame camera is 1024×1024 pixels with a variable gain and 5,000-μs exposure.

In addition, an Allied Vision Prosilica GT 1290 Gigabit Ethernet HD monochrome camera provides the operator with a shadowgraph view of droplet deployment prior to the droplet translation into the combustion chamber. Resolution was set at 960×960 pixels, and video captured at 30 fps. Exposure is 25 ms, and the gain is adjusted automatically throughout testing.

Data from the cameras is recorded on a local PC running NorPix StreamPix digital video recording software. Images are saved in 8-bit .seq format, a NorPix proprietary format that can be converted to an audio video interleave (.avi) or tagged image file format (.tiff) file.

NASA researchers believe the new configuration will allow them to continue performing normal-gravity liquid droplet combustion experiments without requiring Zero Gravity test equipment. Also, it is their hope that the experimental configuration will enable the development of a similar capability for conducting high-pressure combustion and supercritical oxidation research on the International Space Station.

About Mikrotron, a brand of SVS-Vistek GmbH

SVS-Vistek GmbH acquired 100% of the shares of Mikrotron GmbH with retroactive effect from 01 January 2022. Through this integrative merger of the two companies under the umbrella of TKH Vision, the two companies combine their strengths and competencies and place their camera expertise on a strong entrepreneurial basis. 

Now a brand of SVS-Vistek, Mikrotron is internationally renowned for small and particularly robust high-speed cameras in the industrial image processing market. Digital high-speed cameras have outstanding technical performance characteristics and are widely used in industrial and scientific applications as well as in the field of sports, advertising and by nature filmmakers.