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Full-Text Articles in Mechanical Engineering

Nanosecond Near-Spinodal Homogeneous Boiling Of Water Superheated By Pulsed Co/Sub 2/ Laser, Sergey I. Kudryashov, Kevin Lyon, Susan D. Allen Mar 2007

Nanosecond Near-Spinodal Homogeneous Boiling Of Water Superheated By Pulsed Co/Sub 2/ Laser, Sergey I. Kudryashov, Kevin Lyon, Susan D. Allen

Mechanical Engineering - Daytona Beach

The fast boiling dynamics of superheated surface layers of bulk water cavitating under near-spinodal conditions during nanosecond C O2 laser heating pulses was studied using contact broad-band photoacoustic spectroscopy. Characteristic pressure-tension cycles recorded by an acoustic transducer at different incident laser fluences represent (a) weak random oscillations of transient nanometer-sized near-critical bubbles-precursors and (b) well-defined stimulated oscillations of micron-sized supercritical bubbles and their submicrosecond coalescence products. These findings provide an important insight into basic thermodynamic parameters, spatial and temporal scales of bubble nucleation during explosive liquid/vapor transformations in absorbing liquids ablated by short laser pulses in the thermal confinement regime. …


On Damping And Fluidelastic Instability In A Tube Bundle Subjected To Two-Phase Cross-Flow, Joaquin Moran, David S. Weaver Jan 2007

On Damping And Fluidelastic Instability In A Tube Bundle Subjected To Two-Phase Cross-Flow, Joaquin Moran, David S. Weaver

Publications and Scholarship

An experimental study was conducted to investigate damping and uidelastic instability in tube arrays subjected to twophase cross-ow. The purpose of this research was to improve our understanding of these phenomena and how they are affected by void fraction and ow regime. The working uid used was Freon 11, which better models steam-water than air-water mixtures in terms of vapour-liquid mass ratio as well as permitting phase changes due to pressure uctuations. The damping measurements were obtained by plucking the monitored tube from outside the test section using electromagnets. An exponential function was tted to the tube decay trace, producing …