Temperature and Motion Tracking of Metal Spark Sprays

Liu, Yudong; Urban, James L.; Xu, Chuanlong; Fernandez-Pello, Carlos

doi:10.1007/s10694-019-00847-3

Cited by 23 publications

(9 citation statements)

References 27 publications

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“…Based on the analysis presented above, a complete 'oxidation-melting phase diagram' may be constructed to depict regions of no/incomplete and full melting of the chip in T 0 versus L c space, see figure 10. The vertical demarcation line shows the bound determined by c 2 L 2 c /K p = t ox < t f where the typical particle flight time t f 600 ms, see also [44]. This diagram shows unmelted (grey, t m > t ox > t f ), partially melted (orange, t m < t ox < t L ) and fully melted (blue, t m < t L < t ox ) chips in various hues corresponding to different values of the parameter c. For a given value of c, determined by oxidation duration/kinetics and chip dimension, the inequality in equation (4.12) determines the region where melting (either partial or full) of the chips will occur.…”

Section: (Iii) Explaining the Occurrence Of Melted/unmelted And Parti...mentioning

confidence: 99%

Of fiery sparks and glittering spots: melting-resolidification and spherical particle formation in abrasion

et al. 2023

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The curious occurrence of perfectly spherical particle debris when a steel substrate is slid against a hard abrasive was first documented by Robert Hooke in the seventeenth century. Similar observations now abound in other abrasion-type processes, from industrial grinding to sliding rock faults. The prevalent hypothesis, originally proposed by Hooke, is that these particles form due to high local temperatures, resulting in particle ejection, melting and resolidification. In this work, we revisit this hypothesis, using a model steel-abrasive contact, a combination of in situ and post-process investigations, and complementary analytical calculations. Our results reveal two primary findings—firstly, the temperature of particles ejected from the contact zone is far from the melting point, and secondly, exothermic surface oxidation plays a critical role in actually melting the particle. Melting is either complete or partial, leading to spherical particles or ‘slivers’, as described originally by Hooke. Finally, we confirm that resulting particle surface patterns are typical of rapid solidification from the melt. Apart from throwing light on a centuries’ old curiosity, our results precisely quantify the melting-resolidification process, with implications for a variety of applications, ranging from abrasion and powder production to the formation of micrometeorite dust.

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Section: (Iii) Explaining the Occurrence Of Melted/unmelted And Parti...mentioning

confidence: 99%

Of fiery sparks and glittering spots: melting-resolidification and spherical particle formation in abrasion

et al. 2023

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“…where T is temperature, R and G are the radiation intensity of the red and green channels, 𝑔 is the function between T and 𝑅 𝐺 ⁄ , which is calibrated through the experiment, as discussed in Section 5.4. The detailed implementation and verification of the CRP technique can be found elsewhere in [29].…”

Section: Principle Of Light Field Sectioning Pyrometrymentioning

confidence: 99%

“…Temperature calibration was carried out to establish a relationship between the temperature and the color ratio (CR) of the flame spectral radiation captured by the CCD sensor [29]. A pre-calibrated blackbody furnace (Land R1500T) is used as the standard instrument for temperature calibration.…”

Section: Temperature Calibration Through a Blackbodymentioning

confidence: 99%

Spatial resolution of light field sectioning pyrometry for flame temperature measurement

Liu

Zhu

Wang³

et al. 2021

Optics and Lasers in Engineering

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“…Recently, several studies have been conducted in an attempt to solve this problem [16][17][18][19][20][21][22][23]. In order to conduct this research, a series of prescribed fire experiments within pine forests were performed to study the generation of firebrands and their properties as a function of fire behavior [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, particle tracking velocimetry and flame front detection techniques were also tested to explore [21] commercial aircraft debris striking. One study [22] presented a methodology that combined color-ratio pyrometry and particle streak-tracking velocimetry, together with digital image processing, in order to obtain non-intrusive measurements of the temperature, velocity, and size of multiple sparks in a spray. Despite the existing studies, a reliable method for obtaining the thermal and physical characteristics of firebrands in both laboratory and field conditions has not yet been developed.…”

Section: Introductionmentioning

confidence: 99%

Determination of Firebrand Characteristics Using Thermal Videos

Prohanov

Filkov

Касымов

et al. 2020

Fire

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Burning firebrands generated by wildland or prescribed fires may lead to the initiation of spot fires and fire escapes. At the present time, there are no methods that provide information on the thermal characteristics and number of such firebrands with high spatial and temporal resolution. A number of algorithms have been developed to detect and track firebrands in field conditions in our previous study; however, each holds particular disadvantages. This work is devoted to the development of new algorithms and their testing and, as such, several laboratory experiments were conducted. Wood pellets, bark, and twigs of pine were used to generate firebrands. An infrared camera (JADE J530SB) was used to obtain the necessary thermal video files. The thermograms were then processed to create an annotated IR video database that was used to test both the detector and the tracker. Following these studies, the analysis showed that the Difference of Gaussians detection algorithm and the Hungarian tracking algorithm upheld the highest level of accuracy and were the easiest to implement. The study also indicated that further development of detection and tracking algorithms using the current approach will not significantly improve their accuracy. As such, convolutional neural networks hold high potential to be used as an alternative approach.

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Temperature and Motion Tracking of Metal Spark Sprays

Cited by 23 publications

References 27 publications

Of fiery sparks and glittering spots: melting-resolidification and spherical particle formation in abrasion

Of fiery sparks and glittering spots: melting-resolidification and spherical particle formation in abrasion

Spatial resolution of light field sectioning pyrometry for flame temperature measurement

Determination of Firebrand Characteristics Using Thermal Videos

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