ORCID
0009-0003-4710-8975
Date of Award
2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Mechanical Engineering
First Advisor
Jeffrey Marshall
Abstract
A bounded vortex flow is a hydrodynamic approach for removing particles from a surface without scattering them onto nearby surfaces. This flow is generated by a nozzle that combines azimuthally tilted downward jets in a circular array located about a central suction port. When the nozzle is directed toward a flat surface (called the impingement surface), a strong wall-normal intake vortex below the suction outlet is observed to develop, which generates a strong shear stress on the surface. This shear stress acts to remove particles adhered to the impingement surface, along with enhancement of heat or mass transfer. In a typical cleaning scenario, the nozzle would translate above the impingement surface to remove particulates over a region. This thesis first presents a computational study of the effects of nozzle translation on the bounded vortex flow field. The translation of the nozzle induces a bending of the vortex in the downstream direction, where the vortex bending increases as translation speed rises. An oscillatory motion was observed where the bounded vortex resists the induced bending and rotates about a mean position on the impingement surface downstream of the suction port. At sufficiently large translation speeds, a bifurcation occurs beyond which the vortex cannot sustain the oscillatory state and instead flows into the nozzle wake. In this latter state, the vortex detaches from the impingement surface and is carried downstream, effectively limiting the particle removal effectiveness of the device. In addition to the computational study of the bounded vortex flow field subject to nozzle translation, an experimental study was conducted to examine the effectiveness of the bounded vortex flow device for particle removal from a surface in the presence of nozzle translation along the surface. The cleaning effectiveness was analyzed as a function of flow rate through the nozzle, particle size, and nozzle translation velocity relative to the impingement surface. To complement these experiments on particle mitigation, numerical computations of the flow field were used to obtain a relationship between nozzle flow rate and maximum shear stress on the impingement surface. This shear stress is then used to theoretically predict the onset of particle motion. The combined computational and experimental findings provide insights into optimizing the bounded vortex flow for applications in surface cleaning and heat transfer enhancement, where the nozzle would move relative to a surface.
Language
en
Number of Pages
140 p.
Recommended Citation
DesRoberts, Benjamin, "Effect of Nozzle Translation on a Bounded Vortex Flow Field and Particle Removal from a Surface" (2025). Graduate College Dissertations and Theses. 2024.
https://scholarworks.uvm.edu/graddis/2024
