Granular flows in rotating drums transition between two regimes characterized by straight and curved free surfaces. Here we predict this behavior using a depth-integrated theory applicable to general eroding flows. Closure is achieved by a local μ(I) rheology and an equation for kinetic energy. Spanning the transition, the theory yields relations for all flow properties in terms of a single dimensionless rotation rate. In accord with experiments, distinct scaling laws are obtained for slow and fast rates, dominated respectively by local energy dissipation and longitudinal energy transfer.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1103/PhysRevE.93.030902 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Numerical simulation of coal particle motion characteristics in the envelope region of spiral drum based on discrete element method.
Sci Rep
January 2025
College of Mechanical and Electrical Engineering, Zhoukou Normal University, Zhoukou, 466000, China.
In order to study the movement characteristics of coal particles in the coal loading process of spiral drums, the spiral drum of a certain type of shearer was taken as the research object, and the intrinsic parameters of the materials were calibrated through the determination results of coal sample properties, the relevant parameters of coal particle adhesion were determined, and a discrete element model of spiral drum coal loading was established. The distribution of coal particle movement subsequent to the fracture of the coal wall was derived through simulation. By spatially dividing the envelope region of the spiral drum along the radial and axial directions, the number and velocity distribution of coal particles in different envelope regions were obtained.
View Article and Find Full Text PDFCFD study of self-cleaning system of multi-stage tangential roller threshing unit for precise buckwheat breeding.
Heliyon
March 2024
Department of Zoology, College of Science, King Saud University, P. O. Box 2455, Riyadh, 11451, Kingdom of Saudi Arabia.
Buckwheat is a globally recognized, nutritionally rich crop with robust adaptability, serving as a multi-purpose plant for its health benefits. Achieving precise and mechanized plot seed harvesting is a critical step in obtaining accurate results in breeding experiments. However, plot breeding requires no seed retention, no mixing, and ensures no accumulation of seed in the threshing unit.
View Article and Find Full Text PDFDistribution of residence time in rotary-drum composting and implications for hygienization.
Waste Manag
April 2024
Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization (ARO) - Volcani Institute, Newe Ya'ar Research Center, Ramat Yishai 30095, Israel. Electronic address:
Rotary drums enable rapid composting compared to static systems. Residence times (RT) of 3-5 days are commonly applied to fulfill sanitary requirements and ensure the initial stabilization of organic matter. Practically, RT distribution (RTD) implies that a portion of the feed is discharged earlier than the mean RT, which may not guarantee safe application of the end product.
View Article and Find Full Text PDFHow particle shape affects granular segregation in industrial and geophysical flows.
Proc Natl Acad Sci U S A
February 2024
Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY 14627.
Industrial and environmental granular flows commonly exhibit a phenomenon known as "granular segregation," in which grains separate according to physical characteristics (size, shape, density), interfering with industrial applications (cement mixing, medicine, and food production) and fundamentally altering the behavior of geophysical flows (landslides, debris flows, pyroclastic flows, riverbeds). While size-induced segregation has been well studied, the role of grain shape has not. Here we conduct numerical experiments to investigate how grain shape affects granular segregation in dry and wet flows.
View Article and Find Full Text PDFExperimental and numerical evaluation for drum dynamic reliability under extremely complex working conditions.
Sci Rep
January 2024
School of Mechanical Engineering, Liaoning Technical University, Fuxin, 123000, China.
Coal mining machine drums are prone to damage and malfunction under extremely complex working conditions, which seriously affects the efficiency and safety of coal production. In this paper, based on the theory of coal rock cutting and virtual simulation technology, finite element models of drum cutting coal rock were established and then verified by physical experiments. Through simulation analysis, the dynamic reliability of the drum was studied from three aspects: load, stress and wear, and a mathematical model of drum load was established with respect to the traction speed and drum rotation speed; based on the orthogonal test, the optimal working parameters to improve the wear resistance of the drum were derived.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!