Heat generation in granular materials by friction and plastic deformation
Creators: name: Kisuka, Francisco Fidelis
Publisher: name: University of Surrey
Year: 2023

description: This PhD thesis investigates heat generation in granular materials resulting from
description: mechanical energy dissipation through friction and plastic deformation. The study
description: uses numerical and experimental approaches to analyse the generated heat for
description: particle-substrate contacts and granular mixes of various materials.<br>
description: <br>
description: The numerical study consists of three parts, where theoretical models and finite
description: element methods (FEM) models analyse heat generation during sliding and
description: collisional contacts between a particle and a substrate. The first part examines
description: friction-induced heat generation in particle-substrate sliding contact. The results
description: show that theoretical models can accurately predict temperature rise due to frictional
description: heating, and the FEM model indicates that frictional heat is concentrated in the contact
description: patch vicinity. The second part investigates heat generation associated with plastic
description: deformation during normal impact between an elastic-perfectly-plastic particle and
description: a rigid substrate using FEM and theoretical models. The FEM model agrees with the
description: theoretical model in predicting the generated heat due to plastic deformation. Also,
description: the highest temperatures are generally observed in the subsurface, indicating that
description: heat generation associated with plastic deformation is a volumetric phenomenon.
description: The third part explores heat generation during oblique impacts between a spherical
description: particle and a rigid substrate. It identifies simple theoretical solutions to decouple
description: heat generation from friction and plastic deformation.<br>
description: <br>
description: The experimental studies consist of two setups: an overhead stirrer and a rotating drum.
description: The overhead stirrer setup uses thermocouples to measure the temperature of the
description: granular bed during mixing. The results show that metallic particles heat
description: up faster than plastic and glass particles. Also, a higher temperature is recorded
description: for higher rotation speed, larger particle size, higher fill ratio and larger blade size.
description: For the rotating drum, a thermal camera is used to quantify the bed temperature
description: during the granular mixing. The results reveal that metallic particles lead to a more
description: significant temperature increase, indicating that they generate more heat than
description: nonmetallic particles. Also, a higher fill ratio and higher rotational speeds lead to higher
description: bed temperatures.<br>
description: <br>
description: Overall, the findings from the FEM simulations, theoretical models, and experimental
description: studies contribute to a better understanding of the heat generation mechanisms in
description: granular flows and can inform the development of more accurate predictive
description: models for industrial applications.<br>