On the evolving flow of grains down a chute

Abstract

A continuum model leads to a partial differential equation for the evolving flow of grains down a chute. This is addressed for different effective viscosities in the system. Solutions for small viscosity are obtained which describe separating grains and clashing grains. Steady-state solutions are also found for any viscosity value, these being considered as a large time limit. Restrictions on the steady-state solutions are discussed, along with cases which yield re-structuring within a finite time.

Interference in a three-dimensional array of jets

“…Working similar to that in this and the next two sections holds wherever the secondary vorticity is identically constant: see Section 6. An example for a single jet in which 2) and the input swirl is zero is presented in Figure 2 for two distinct cases, a square and a rectangle. (The numerical work is based on iteration with standard central-differencing throughout.)…”

“…In the relevant food-sorting configuration huge numbers of grains (rice, peas, seeds, etc.) or similar small bodies are let fall rapidly down an inclined chute as discussed in [1,2] and then drop off the end of the chute under gravity. At that stage the multiple grains then form a free-falling sheet in effect but they are viewed individually by means of an inspection laser, any faulty grain is identified and almost immediately an air jet is fired from a multiple high-pressure ejector machine which is intended to knock that faulty grain out of the free-falling sheet.…”