Bo Fan, Tivadar Pongó, Raúl Cruz Hidalgo, Tamás Börzsönyi
{"title":"颗粒形状对沙漏流动的影响","authors":"Bo Fan, Tivadar Pongó, Raúl Cruz Hidalgo, Tamás Börzsönyi","doi":"arxiv-2407.21685","DOIUrl":null,"url":null,"abstract":"The flow rate of a granulate out of a cylindrical container is studied as a\nfunction of particle shape for flat and elongated ellipsoids experimentally and\nnumerically. We find a nonmonotonic dependence of the flow rate on the grain\naspect ratio a/b. Starting from spheres the flow rate grows and has two maxima\naround the aspect ratios of a/b = 0.6 (lentil-like ellipsoids) and a/b = 1.5\n(rice-like ellipsoids) reaching a flow rate increase of about 15% for lentils\ncompared to spheres. For even more anisometric shapes (a/b = 0.25 and a/b = 4)\nthe flow rate drops. Our results reveal two contributing factors to the\nnonmonotonic nature of the flow rate: both the packing fraction and the\nparticle velocity through the orifice are nonmonotonic functions of the grain\nshape. Thus, particles with slightly non-spherical shapes not only form a\nbetter packing in the silo but also move faster through the orifice than\nspheres. We also show that the resistance of the granulate against shearing\nincreases with aspect ratio for both elongated and flat particles, thus change\nin the effective friction of the granulate due to changing particle shape does\nnot coincide with the trend in the flow rate.","PeriodicalId":501146,"journal":{"name":"arXiv - PHYS - Soft Condensed Matter","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Effect of particle shape on the flow of an hourglass\",\"authors\":\"Bo Fan, Tivadar Pongó, Raúl Cruz Hidalgo, Tamás Börzsönyi\",\"doi\":\"arxiv-2407.21685\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The flow rate of a granulate out of a cylindrical container is studied as a\\nfunction of particle shape for flat and elongated ellipsoids experimentally and\\nnumerically. We find a nonmonotonic dependence of the flow rate on the grain\\naspect ratio a/b. Starting from spheres the flow rate grows and has two maxima\\naround the aspect ratios of a/b = 0.6 (lentil-like ellipsoids) and a/b = 1.5\\n(rice-like ellipsoids) reaching a flow rate increase of about 15% for lentils\\ncompared to spheres. For even more anisometric shapes (a/b = 0.25 and a/b = 4)\\nthe flow rate drops. Our results reveal two contributing factors to the\\nnonmonotonic nature of the flow rate: both the packing fraction and the\\nparticle velocity through the orifice are nonmonotonic functions of the grain\\nshape. Thus, particles with slightly non-spherical shapes not only form a\\nbetter packing in the silo but also move faster through the orifice than\\nspheres. We also show that the resistance of the granulate against shearing\\nincreases with aspect ratio for both elongated and flat particles, thus change\\nin the effective friction of the granulate due to changing particle shape does\\nnot coincide with the trend in the flow rate.\",\"PeriodicalId\":501146,\"journal\":{\"name\":\"arXiv - PHYS - Soft Condensed Matter\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-07-31\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"arXiv - PHYS - Soft Condensed Matter\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/arxiv-2407.21685\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - PHYS - Soft Condensed Matter","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2407.21685","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Effect of particle shape on the flow of an hourglass
The flow rate of a granulate out of a cylindrical container is studied as a
function of particle shape for flat and elongated ellipsoids experimentally and
numerically. We find a nonmonotonic dependence of the flow rate on the grain
aspect ratio a/b. Starting from spheres the flow rate grows and has two maxima
around the aspect ratios of a/b = 0.6 (lentil-like ellipsoids) and a/b = 1.5
(rice-like ellipsoids) reaching a flow rate increase of about 15% for lentils
compared to spheres. For even more anisometric shapes (a/b = 0.25 and a/b = 4)
the flow rate drops. Our results reveal two contributing factors to the
nonmonotonic nature of the flow rate: both the packing fraction and the
particle velocity through the orifice are nonmonotonic functions of the grain
shape. Thus, particles with slightly non-spherical shapes not only form a
better packing in the silo but also move faster through the orifice than
spheres. We also show that the resistance of the granulate against shearing
increases with aspect ratio for both elongated and flat particles, thus change
in the effective friction of the granulate due to changing particle shape does
not coincide with the trend in the flow rate.