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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

EXPERIMENTAL INVESTIGATION ON CRYOGENIC QUENCHING CHARACTERISTICS OF ROCK IN LIQUID NITROGEN AND THE ENHANCING EFFECTS OF SURFACE STRUCTURING

Get access (open in a dialog) DOI: 10.1615/IHTC16.bae.021891
pages 639-646

Résumé

Cryogenic quenching of sandstone in LN2 was experimentally studied in this paper. The quenching samples were cylinders 1 inch in diameter and 60mm in length. As a baseline case, the rock surface was polished by 1500 grit sandpaper. Circumferential grooves 0.2mm in depth and 80-120 grit sand coatings were also prepared on rock surface to investigate their influences on cryogenic quenching. It was found that the rock surface polished by 1500 grit sandpaper can increase the Leidenfrost temperature by 80°C compared to the copper sample. SEM images revealed the presence of pores and cavities with multi-scale dimensions on rock surface. These porous structures can induce heterogeneous bubble nucleation and contribute to earlier vapor film collapse. The grooves and sand particle coatings can further enhance the heat transfer in film and transition boiling regimes. Smaller groove intervals and larger sand concentrations would lead to more significant heat transfer enhancement. The present results demonstrate the great potential of rock materials in accelerating cryogenic quenching rates by shortening film boiling duration and improving Leidenfrost temperatures.