Feedwater heaters have suffered premature failures in the desuperheating zone resulting from a combination of high cross flow velocities and relatively long baffle spacing. High steam flows coupled with longer unsupported tube spans necessary to keep pressure drops low and tube walls dry create an increased probability for flow induced vibration. This vibration is primarily the result of a fluidelastic whirling of the tube. The most significant factor in the calculation of the natural frequency of the tube is unsupported span length. The natural frequency varies as the square of the unsupported span. Keeping the span short is critical in avoiding flow induced vibration. No-Tubes-in-the-Window (NTIW) baffling allows the use of intermediate support plates without affecting the mean flow velocity in the baffle space. This allows the thermal design engineer the distinct advantage of providing a design with a very high safety margin at any anticipated overload condition. The asymmetrical flow pattern necessitated by the U-tube design of high pressure feedwater heaters can be appropriately modeled to yield an overall design heat transfer coefficient.
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ASME 2009 Power Conference
July 21–23, 2009
Albuquerque, New Mexico, USA
Conference Sponsors:
- Power Division
ISBN:
978-0-7918-4350-5
PROCEEDINGS PAPER
Solving the Flow Induced Vibration Problem in Desuperheating Zones of Feedwater Heaters by Using No-Tube-in-the-Window (NTIW) Baffling
Thomas J. Muldoon
Thomas J. Muldoon
American Exchanger Services, Inc. & Heat Transfer Specialists, Hartford, WI
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Thomas J. Muldoon
American Exchanger Services, Inc. & Heat Transfer Specialists, Hartford, WI
Paper No:
POWER2009-81222, pp. 217-222; 6 pages
Published Online:
September 22, 2010
Citation
Muldoon, TJ. "Solving the Flow Induced Vibration Problem in Desuperheating Zones of Feedwater Heaters by Using No-Tube-in-the-Window (NTIW) Baffling." Proceedings of the ASME 2009 Power Conference. ASME 2009 Power Conference. Albuquerque, New Mexico, USA. July 21–23, 2009. pp. 217-222. ASME. https://doi.org/10.1115/POWER2009-81222
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