3D Printing of Spark-Ignited Flame Kernels, Experimentally Captured by 3D-Computer Tomography and Multi-Directional Schlieren Photography

Autor:	Yu Saiki, Kimihiro Nagase, Yuta Ishiko, Naoki Hayashi, Ahmad Zaid Nazari, Kazuma Kakimoto, Yojiro Ishino
Rok vydání:	2017
Předmět:	Materials science business.industry Turbulence Mechanical Engineering Photography Synthetic schlieren Condensed Matter Physics law.invention Ignition system Optics Mechanics of Materials law Spark (mathematics) Shadowgraph General Materials Science Tomography business Schlieren photography
Zdroj:	Journal of Heat Transfer. 139
ISSN:	1528-8943 0022-1481
DOI:	10.1115/1.4035583
Popis:	Non-scanning 3D-CT(Computer Tomography) technique employing a multi-directional quantitative schlieren photographic system with flash light source, has been performed to obtain instantaneous density distributions of spark-ignited laminar / turbulent flame kernels. For simultaneous schlieren photography, the custom-made 20-directional schlieren camera was constructed and used. The concept of the multi-directional shclieren system is shown in top-right figure. Each quantitative schlieren optical system, indicated in top-left figure, is characterized by a rectangular-shaped right source with uniform luminosity. Middle-left picture gives the appearance of the multi-directional schlieren camera. The flame kernels are made by spark ignition for a fuel-rich propane-air premixed gas (flow velocity :1.0 m/s, equivalence ratio :1.4 ). Spark electrodes of 0.4 mm diameter with 1.0 mm gap are used. First, development of laminar flame kernel is indicated in high-speed images of middle-right figure. 3D printed model of the CT reconstruction result (left in bottom-left photograph) shows the spherical shape of flame kernel with a pair of deep wrinkles. The wrinkle is considered to be caused by spark electrodes. Next turbulent flame kernel behind turbulence promoting grid is selected (turbulence intensity 0.26 m/s). The high-speed images of bottom-right figures show corrugated flame shape. 3D model of CT result (right in bottom-left photo.) expresses the instantaneous 3D turbulent flame kernel shapes. These 3D solid models based on 3D-CT reconstructed data of 2 ms, are 3D-printed as 2 times large size for threshold density level of 0.7 kg/m3.
Databáze:	OpenAIRE
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