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Full-Text Articles in Mechanical Engineering

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 …


Damping Measurements In Tube Bundles Subjected To Two-Phase Cross Flow, Joaquin Moran, David S. Weaver Jan 2006

Damping Measurements In Tube Bundles Subjected To Two-Phase Cross Flow, Joaquin Moran, David S. Weaver

Publications and Scholarship

An experimental study was conducted to investigate twophase damping in tube arrays. The objective was to compare different measurement methodologies in order to obtain a more reliable damping estimate. This will allow for improved guidelines related to failures due to fluidelastic instability in tube bundles. The methods compared were the traditionally used halfpower bandwidth, the logarithmic decrement and an exponential fitting to the tube decay response. The working fluid used was Refrigerant 11 (Freon), which better models the real steamwater problem, as it allows for phase change. The void fraction was measured using a gamma densitometer, introducing an improvement over …