Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 121-122). Also available via the Internet.

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

LD2668 .T4 1947 H37 / Master of Science

No description available.

Approved for public release; distribution is unlimited / The time varying development and structure of Dean vortices were studies using flow visualization. Observations were made over a range of Dean numbers from 40 to 200 using a transparent channel with mild curvature, 40:1 aspect ratio, and an inner to outer radius ratio of 0.979. Seven flow visualization techniques were tried but only one, a wood burning smoke generator, produced usable results. Different vortex characteristics were observed and documented in sequences of photographs space one quarter of a second apart at locations ranging from 85 to 135 degrees from the start of curvature. Evidence is presented that supports the twisting/rocking nature of the flow. / http://archive.org/details/flowvisualizatio00bell / Lieutenant, United States Navy

The current knowledge of the performance characteristics of Centrifugal Tensioned Metastable Fluid Detectors is limited. While a theoretical treatment and experience with bubble chambers may be applied with some degree of success, they are no substitute for experimental and operational knowledge of real CTMFD systems. This research, as with other investigations into CTMFD systems in the past, applies theory and simulations. In addition, however, an experiment was conducted that for the first time attempts to determine the threshold energy for triggering a CTMFD system in a controlled manner. A CTMFD system works in a manner similar to classic bubble chambers. A liquid is brought to an unstable state in which it is favorable to form a volume of vapor; using centrifugal techniques similar to those employed in a Briggs apparatus, the pressure in the sensitive region can be brought to extremely low values, placing the liquid in a tensile state. In such states, the energy necessary to cause the formation of macroscopic bubbles can be vanishingly small, depending on the degree of tension. When such bubbles form in a CTMFD, if they have a size bigger than a critical value, they will grow until a large vapor column forms in the sensitive region of the CTMFD. The experiment developed for this research employed a carefully-controlled laser to fire pulses of known energies into the sensitive region of a CTMFD. By varying the laser power, the threshold values for the triggering energy of a CTMFD can be found. The experiment and simulation demonstrated the ability of the facilities to test CTMFD systems and the potential to extract their operational characteristics. The experiment showed a certain viability for the technique of laser-induced cavitation in a seeded fluid, and demonstrated some of the associated limitations as well. In addition, the CFD framework developed here can be used to cross-compare experimental results with computer simulations as well as with the theoretical models developed for this research.

The present study aims to explore flow behavior in the mold during centrifugal casting process by numerical simulations. The theoretical model comprises two groups of steady conservation equations of mass and momentum and the governing equations are solved numerically with k-£` turbulence model and iterative SIMPLE(Semi-Implicit for Pressure-Linked Equations) algorithm to determine the flow property. The numerical results indicate that the melt liquids of titanium compound metal flow near the walls in the high rotation rate. With the high rotation rate, the outflow velocity is rapid. The products depend on the flow of the melt liquids. The flow is rapid, the filled process is quick, and the temperature is uniform. But if the flow is slow, the temperature is not uniform in the filled process. Therefore, the products may result in faults. When the rotation rate is up to 50 rpm, the melt liquids flow near the walls with the affect of centrifugal force. The velocity is larger than the velocity with zero rotation rate . Thus the flow with rotation rate can help to fill quickly, and reduce the temperature loss.

Conventionally the size of the back clearance played a great importance on reducing the axial clearance by utilizing the concept that the decreased axial clearance results in lower axial force acting on the impeller. However, from the previous works on the effect of the back clearance on the hydrodynamic forces upon the semi-open impeller showed the opposite trend: increasing the back clearance results in the reduced axial loading. In this work, the CFD simulation of an entire pump and detailed analysis on the back clearance flow are performed. By utilizing the commercially available software, meshing and CFD simulations are performed. LDA data, unsteady pressure data, and pressure distributions on the housing are used to validate the CFD model. The flow field prediction of the back clearance flow is then compared with other researcher’s works of the gap flow analysis between the rotating and stationary disks. The flow field inside the impeller passage, which is very sensitive to the back clearance size, is also studied. The empirical equation for the leakage loss through the balance holes is produced using the CFD predictions.

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy