Improving the Bulk Properties and Fluid-Flow Behavior of Metallic Aluminum Powders through Surface Modification

Restricted (Penn State Only)
Author:
Ludwig, Bellamarie
Graduate Program:
Materials Science and Engineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
August 04, 2017
Committee Members:
  • James Hansell Adair, Dissertation Advisor
  • James Hansell Adair, Committee Chair
  • Carlo G. Pantano, Committee Member
  • Douglas Edward Wolfe, Committee Member
  • Benjamin James Lear, Outside Member
  • Victor A. Bakaev, Special Member
Keywords:
  • Aluminum powder
  • powder flow
  • silanes
  • particle characterization
Abstract:
The reaction of aluminum powder fuel in a steam-combustion reaction is highly exothermic and can be used for thermal power plants to produce energy. This concept is ideal for use in underwater vehicles, where the presence of molecular oxygen negates the use of standard combustion reactions for power and energy generation. A significant technical challenge associated with the use of aluminum powder as a fuel is that powders of fine particle size are cohesive and have poor flow properties due to attractive inter-particulate interactions. Reducing the inter-particulate cohesion through particle surface modification enables successful fuel delivery. This dissertation uses hydrophobic, siloxane based surface treatments to reduce the inter-particulate cohesion of aluminum particles and thus improve the flowability. Chapter 3 focuses on the bulk property enhancement of solution phase methyltriethoxysilane surface modified particles, which was revealed to improve bulk density, reduce cohesion, and improve aeration properties, even at fine particle size. Chapter 4 describes the design of a gas phase deposition process using volatized polydimethylsiloxane in a fluidized bed, which also subsequently improved the flowability of the treated powder. Chapter 5 discusses the development of an in situ technique to study fluidization behavior in an aerated environment through powder column expansion and estimation of minimum fluidization velocities. Overall, this work contributes to the development of a powder fuel to support the design of an aluminum powder fuel-steam power plant for use in underwater power and energy generation.