Multilayered particulate fouling: Deposition & breakage.

Cohesive powder in flight can deposit to form loose structures created by multiple layers of material that can be easily eroded. It is an intrinsic feature of nature e.g. sediments, snow, and leads to complex fouling dynamics in a myriad of industrial operations e.g. pharmaceutics, foods, energy, environmental technology. The deposition of particles and the formation of monolayers has been studied extensively, for example in combustors, nuclear reactors or solar panels. It is driven by particle-wall adhesive forces and the near-wall turbulence, and thus, it is primarily dominated by the flow surrounding a structure. However, far less is known about the structural effects: how particle-particle cohesive forces lead to the formation of more complex multilayer structures that are dynamic, constantly growing and breaking due to the interplay between cohesion and hydrodynamic stresses. State-of-the-art research tries to understand how deposits are layered, how larger structures consolidate and age e.g. dry, sinter and how they respond to external stresses and break upon the impact of particles or the action of gravity. These are open but critical questions to industries handling cohesive powders, which struggle to predict when deposits appear, how to prevent or remove them and critically, how to control their impact on transport phenomena e.g. heat exchangers, reactors, health and safety e.g. ash, emissions, furnaces, burners, product properties e.g. silos, mixers, granulators, coaters, or performance e.g. conveyors, nozzles, packaging. This work will tackle some of these issues studying in detail the state-of-the-art in the study of deposition of cohesive powders taking special attention to visualisation techniques, the development of experimental techniques and prototype chambers.

Supervisor name: 
Victor Francia
Supervisor and Deputy email addresses: 
vf9@hw.ac.uk