Pah Chen

Date of Award


Document Type


Degree Name

Master of Science (M.S.) in Applied Science


Applied Science

Physical Description

1 online resource (68 leaves, ill. (part mounted) 28 cm.)


Fluidic devices, Particles




This study was directed toward the development of a bistable wall attachment Flip-Flop device which was capable of directionally controlling particle flow. The particles were transported by a fluid stream which under the influence of wall attachment. The dominant criteria in the development of the device was the achievement of the highest recovery of particles at the active output, without destroying the wall attachment of the fluid stream The experiment was conducted in several distinct stages; each of which was concerned with at least one aspect of wa1l attachment or particle flow. Results derived from one test were used to develop the criteria for the next experimental arrangement. Two experimental models were constructed: one of plywood with only one attachment wall, and one of plexiglas which had two attachment walls and was bistable. The plywood model was used in testing wall attachment and particle recovery as a function of the attachment wall angle. From these tests it was concluded that the optimum wall angle was 18 degrees from the center line of the device. Observations of particle action in the plywood model led to the incorporation of additional features in the plexiglas model. They were: an extended nozzle, the elimination of the separation bubble, and the development of smooth transitions at the corners. The plexiglas model was used to investigate optimum splitter location, the effect of jet velocity on recovery efficiency, the effect of vents on the performance of the device, and the performance of the device using a water jet. In the last stages of testing, moving parts and additional output features were used in conjunction with the bistable device to improve the collection efficiency. Some observations resulting from the data gathered in the various tests include: 1. The higher the jet velocity, the greater the wall attachment. 2. The higher the density and viscosity of the fluid stream the greater the recovery of particles at the active output. 3. Particles with large inertial forces were controlled less by the attached jet stream. The addition 0f vents in the device may produce greater particle recovery. 5. The use of moving parts and variations in the output leg design can produce 100 percent particle recovery. This study indicated that it was possible to control the directional flow of particles with the bistable wall attachment device which was developed. However, the pure fluid bistable device could not achieve 100 percent recovery of particles. The addition of moving parts or variations in the output leg design can produce 100 percent recovery of the particles. The use of a bistable device could provide simplicity, reliability and adaptability in transporting materials for industrial processes.

Persistent Identifier