Analysis of the velocity field of granular hopper flow

TL;DR

This paper analyzes the radial velocity profiles of granular flow in a conical hopper, proposing a new Local Mass Flow index to better classify flow regimes based on simulated velocity data.

Contribution

It introduces a Local Mass Flow index derived from velocity profiles to improve classification of granular flow regimes in hoppers.

Findings

Velocity profiles follow an approximate power law with distance from the orifice.

Differences exist between flow along the cone axis and its wall.

The Local Mass Flow index shows promise for better flow regime classification.

Abstract

We report the analysis of radial characteristics of the flow of granular material through a conical hopper. The discharge is simulated for various orifice sizes and hopper opening angles. Velocity profiles are measured along two radial lines from the hopper cone vertex: along the main axis of the cone and along its wall. An approximate power law dependence on the distance from the orifice is observed for both profiles, although differences between them can be noted. In order to quantify these differences, we propose a Local Mass Flow index that is a promising tool in the direction of a more reliable classification of the flow regimes in hoppers.