Associate Professor Craig Wheeler

© 2015 Elsevier Ltd. All rights reserved. The energy loss due to indentation rolling resistance in a conveyor belt system can account for up to 60% of the total power usage. It arises due to an asymmetric pressure distribution as a viscoelastic belt cover is indented by a rigid idler roll. This causes a retarding moment on the idler roll, dependent on the load, speed, idler diameter and the properties of the conveyor belt cover. As pouch conveyor systems become more prevalent in industry, the supporting structure, and thus the indentation rolling resistance of such systems is of importance. These designs typically employ curved belt profiles, or spherical idlers in order to aid belt tracking and closing. From this, a spherical indentation into a generalised Maxwell backing is modelled, and compared with experimental values. In addition to this, the strain dependency across the contact is investigated.

© 2016 The indentation rolling resistance of conveyor belts is an important design consideration for long belt conveyors and can also be important for heavily loaded belt conveyors. Indentation rolling resistance is dependent on the properties of the conveyor belt, including the carcass and bottom cover as well as properties of the belt conveyor including induced loads, belt speed, ambient temperature and idler roll diameter. A purpose built laboratory test facility is described to measure the indentation rolling resistance of conveyor belts. The test facility is designed to accept both fabric and steel cord belts and test over a range of typical operating parameters and conditions. Results are presented for a range of test parameters, including; load, belt speed, idler roll diameter, ambient temperature and bottom cover compound. Application of the test data to conveyor design is also presented with the aim being to show how the test facility can be used to improve the accuracy of conveyor belt tension calculations by more accurately evaluating the performance of different rubber compounds and belt constructions.

© 2016 Springer Science+Business Media Dordrecht The accuracy of analytical models used to predict the indentation rolling resistance of belt conveying systems depends on the method of testing the material properties. Due to the limitations and inconsistency of obtaining material properties using mechanical methods, it is becoming more common for viscoelastic behaviour to be represented by non-mechanical models, such as dielectric models. Dielectric models can lead to the same mathematical predictions as mechanical models; however, the experimental work is highly accurate and can be performed over a much greater frequency range than mechanical testing. This paper introduces a dielectric energy loss model which uses dielectric methods to measure the viscoelastic material properties of the bottom cover of conveyor belt. The model is compared to actual indentation rolling resistance data obtained from tests performed at the University of Newcastle on a purpose built test facility.

The bulk material on a belt conveyor deforms itself due to the run through idler stations. The deformation results in energy losses which are summarised in the bulk solid flexure resistance. The right understanding of the interaction between bulk material and idler stations is important for the prediction of this resistance and the idler loads. For the calculation of the bulk material behaviour on the belt the classical analytical approach by Krause and Hettler [1] was extended by Wheeler [2] with a Finite Difference model to consider the belt deflection. DEM simulation and experimental measurements of the belt deflection were used by Ilic [3] to predict the bulk material behaviour. This paper will use coupled FEM-DEM simulations for a pure numerical analysis of the interaction between bulk material, belt and idler. In this approach a simplified FEM model for a fabric belt is combined with a calibrated DEM model for cohesionless grit The model and the results of the coupled simulation will be presented. The paper will highlight the influence of belt velocity, belt pre-tension and idler distance on the behaviour of the bulk material as well as how this approach can be used to determine the bulk solid flexure resistance. Further, the new results are compared with the findings of previous works and experimental data.

The bulk material on a belt conveyor deforms itself due to the run through idler stations. The deformation results in energy losses which are summarised in the bulk solid flexure resistance. The right understanding of the interaction between bulk material and idler stations is important for the prediction of this resistance and the idler loads. For the calculation of the bulk material behaviour on the belt the classical analytical approach by Krause and Hettler [1] was extended by Wheeler [2] with a Finite Difference model to consider the belt deflection. DEM simulation and experimental measurements of the belt deflection were used by llic [3] to predict the bulk material behaviour. This paper will use coupled FEM-DEM simulations for a pure numerical analysis of the interaction between bulk material, belt and idler. In this approach a simplified FEM model for a fabric belt is combined with a calibrated DEM model for cohesionless grit The model and the results of the coupled simulation will be presented. The paper will highlight the influence of belt velocity, belt pre-tension and idler distance on the behaviour of the bulk material as well as how this approach can be used to determine the bulk solid flexure resistance. Further, the new results are compared with the findings of previous works and experimental data.

This article discusses how determining the viscoelastic properties of the cover material of a conveyor belt, using different rheological test modes, can result in significant differences in properties for the same material and testing conditions. The viscoelastic properties are applied to two mathematical models used to predict and compare the indentation rolling resistance performance of two rubber compounds. This article demonstrates how inaccuracies in the testing of the viscoelastic properties could result in a material with higher indentation rolling resistance properties being selected for a conveying system, making the power consumption of the system larger than necessary. © 2014 Wiley Periodicals, Inc.

This article presents the outcomes from a series of physical experiments to measure the air entrainment rates encountered within a stream of freefalling particles. The experimental work presented spans a range of particle parameters and hopper geometries. From these results a new theory for the prediction of air entrainment is developed and presented. This new method was developed specifically to facilitate a better understanding in the area of fugitive dust control associated with material handling systems, which are driven by the air entrainment during freefalling. From the work presented in this article, a better prediction capability of freefalling bulk materials in either constrained, or unconstrained systems, will allow for the optimization of either passive or active dust control strategies. This article presents several distinct sections that detail the experimental work used to determine the freefall stream parameters that were conducted to allow the development of the entrainment equations. © 2013 Taylor & Francis Group, LLC.

A co-operation among Universities of Newcastle, Australia, and Magdeburg, and Germany, is established to develop and apply the new analysis methods such as Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD), for prediction of diffuse dust emission from dust exhaustion plants. The combined analysis of DEM and CFD includes two CFD simulations, the air flow in the bulk material stream and the air flow around the bulk material stream. The boundary conditions for the calculation of the air flow in the enclosure are set. The results of CFD simulations show that the exhausted air does not come from the impact zone of the material stream on the receiving belt conveyor, but from the opening above the incoming conveyor belt. It is also found that the air with the highest dust content can be found on top of the receiving conveyor.

A technique to simulate airflow around transfer chutes that involves linking Discrete Element Method (DEM) commercial package Rocky and Computational Fluid Dynamics (CFD) commercial package ANSYS Fluent is proposed. The flow of particles is first calculated in the DEM domain; after that continuum parameters of this flow (porosity, mean particle size and cell-averaged particles velocities) are calculated and used as input into ANSYS Fluent CFD package for the solution of the airflow. This solution is carried out using a single-phase moving porosity approach with User Defined Functions (UDF) for porosity and particle-based momentum terms in Fluent based on phenomenological interaction laws. The comparison against experimental results for a laboratory-scale transfer chute demonstrates a good match between experimental and computational data. Several turbulence models and particle-gas interaction laws have been tested and it was concluded that for this problem the choice of interaction laws and turbulence models does not affect the results of the simulation to any significant degree.

This paper presents an industrial case study to reduce dust emissions from a grain handling ship loader. The primary objective of the study was to reduce dust emissions to within acceptable environmental levels during ship loading. Several constraints were imposed on the solution due to time and budgetary restrictions, and the inability to add a dust suppression agent to the grain for quality reasons. A number of alternative loading chute configurations and delivery spoon profiles were examined in a pilot-scale test facility. This paper will discuss a number of alternative solutions which were investigated during the course of the study and the critical parameters of the final design. Tests showed that it was not beneficial to decelerate the product stream to keep the relative velocity of the air stream over the grain below the minimum pickup velocity. Instead, it was found that concentrating the product stream and keeping the product velocity high was more beneficial in reducing dust emissions. A reduction of 50% in dust emission was achieved through the use of specifically designed constant radius and parabolic profile loading spoons. The product stream exiting the curved spoons was found to be concentrated and stream-lined, resulting in the dust being contained within the product stream.