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Schlieren Imaging in Materials Processing



Steven P. Mates


Even before Ernst Mach used it to visualize sock waves cast by a supersonic bullet in 1888, the schlieren optical technique has been a valuable diagnostic tool in fluid mechanics, particularly int he fields of aerodynamics and heat convection, where strong density gradients in the flow are able to produce high-contrast schlieren images. Recent advances in high-speed, high resolution CCD imaging technology have faciliated high quality imaging of dynamic phenomena in materials processing operations that involve compressible fluid flow, such as inert gas atomization of molten metals and thermal spraying of protective coatings. This paper describes the use of three types of schlieren optical arrangements to visualize compressible flow patterns produced in these processes using commercially aailable CCD cameras. Factors affecting schlieren sensitivity and image contrast and quality associated with the choice of optical elements, cutoff filter, light source are discussed, as are issues arising from the operational characteristics of most commercial CCD cameras.
The Masonry Society Journal


Flow Visualization, Materials Processing, Schlieren, Thermal Spray


Mates, S. (2008), Schlieren Imaging in Materials Processing, The Masonry Society Journal (Accessed May 23, 2024)


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Created October 16, 2008