Session: FSI-02-02 Tube Arrays - 2

Paper Number: 106882

106882 - A Method for Modeling Fluidelastic Instability in Tube Arrays Subjected to Two-Phase Flows 

In the last four decades, a significant effort has been made to study the structural dynamics of tube arrays in heat exchangers.  Different excitation mechanisms that can compromise the integrity of these components have been properly identified, with the Fluidelastic Instability (FEI) receiving the most attention.  As the structure cannot dissipate the energy transferred by the flow, large-amplitude oscillations are generated, and early failure of components is possible.  The problem becomes more difficult to analyze in two-phase flows, where complex flow structures, phase change and uneven density and void distribution affect the occurrence of FEI.

The prediction of FEI has largely been explored using experimental, theoretical or hybrid approaches.    Some numerical methods have been proposed to understand the underlying physical mechanisms that cause the phenomenon, and although promising results shave been achieved, these models are limited by application constraints or very high computational costs.  In this paper, a new model is introduced to predict the onset of FEI in two phase flows across tube arrays.  The time domain model of Hassan and Weaver (Hassan and Weaver 2016, Hassan and Weaver 2017) has been modified and adapted to two-phase flows by discretizing the flow channel between the tubes into layers with individual void fraction values.  The velocity and pressure distribution around the tubes are found using Gaussian integration of the continuity and momentum equations.  Preliminary results obtained for a parallel-triangular array geometry agree well with existing experimental data and demonstrate a substantial improvement in computation time when compared to other models.

References:

Hassan, M. and D. Weaver (2017). "Pitch and mass ratio effects on transverse and streamwise fluidelastic instability in parallel triangular tube arrays." Journal of Pressure Vessel Technology 139(6).

Hassan, M. and D. S. Weaver (2016). "Modeling of streamwise and transverse fluidelastic instability in tube arrays." Journal of Pressure Vessel Technology 138(5).

Presenting Author: Hossein Farani Sani University of Guelph

Presenting Author Biography: Born in 1993 in Tehran, Iran, He went to SAMPAD high school, one of the best high schools in Iran. From that time, he started learning to program and getting familiar with different programming languages. He finished his BSc. from the K.N.Toosi University of Tehran and pursued his study at Tarbiat Modares University. During his Master, he studied on the numerical modeling of fuel injection in diesel engines and published two conference and one ISI papers on the effect of turbulence on the injector's behavior. He graduated in 2017 from Modares University with a high grade and He is now a Ph.D. student at Guelph University, studying the fluid elastic instability of tube bundles in
nuclear steam generators.

Authors:

Hossein Farani Sani University of Guelph
Joaquin Moran Sheridan College
Atef Mohany Ontario Tech University
Marwan Hassan University of Guelph