Experimental analysis of fluid elastic vibrations in rotated square finned tube arrays subjected to water cross flow

Abstract

The majority of the failures of shell and tube heat exchanger tubes are reported due to the flow-induced vibration caused by shell side cross flow. Fluid elastic instability, vortex shedding, and turbulent buffeting are the excitation mechanisms responsible for the failure of the tubes. The failure occurs due to tube-to-tube impacts leading to impaction marks on the tube surface and, subsequently, leading to the failure due to fretting wear and fatigue. The present research work deals with the determination of critical velocity at instability for rotated square finned tube arrays subjected to water cross flow. In all, total six tube arrays are tested with two different pitch ratios, each with a plain tube array, a coarse finned tube array, and a fine finned tube array. Pitch ratios considered in the study are 2.1 and 2.6, while fin densities considered are coarse (4 fpi = 6.35 mm) and fine (10 fpi = 2.54 mm). The effect of array pattern, pitch ratio, and fin density on the onset of instability is studied by conducting experiments in the water cross flow. The effect of tube array pattern is studied by comparing the results of the present study with authors' published results for parallel triangular finned tube arrays in the water cross flow. The study led to the conclusion that the instability threshold is delayed for rotated square tube arrays compared to parallel triangular tube arrays. It is also observed that instability thresholds for coarse and fine finned tubes are delayed compared to plain tubes and is found to be more for finned tubes with higher fin densities.

Keywords

Rotated square tube array critical velocity instability threshold finned tubes plain tubes

Get full access to this article

View all access options for this article.

References

Pettigrew

Taylor

. Fluid elastic instability of heat exchanger tube bundles: review and design recommendations. J Press Vess Technol 1991; 113: 242–256.

Blevins RD. Flow-induced vibration. 2nd ed. Malabar, FL: Krieger Publishing Company, 2001.

Kaneko S, Nakamura T, Inada F, et al. Flow induced vibrations – classifications and lessons from practical experiences. 1st ed. New York: Elsevier Science, 2008.

Halle H, Chenoweth JM and Wambgan MW. Shellside water flow induced vibration in heat exchanger tube configurations with tube pitch-to-diameter ratio of 1.42. In: ASME annual meeting on flow induced vibration in heat transfer equipment, Chicago, IL, USA, 1988, pp.1–16.

Ziada

. Vorticity shedding and acoustic resonance in tube bundles. J Brazil Soc Mech Sci Eng 2006; 28: 186–199.

Weaver

El-Kashlan

. On the number of tube rows required to study cross flow induced vibrations in tube banks. J Sound Vib 1981; 75: 265–273.

Chen

Jendrzejczyk

. Experiments on fluid elastic instability in tube banks subjected to liquid cross flow. J Sound Vib 1981; 78: 355–338.

Mitra

Dhir

Catton

. Fluid elastic instability in tube arrays subjected to Air-Water and Steam-Water cross flow. J Fluids Struct 2009; 25: 1213–1235.

Kienböck

. Vibration characteristics of finned tubes with small fins. VGB Kraftwerkstechnik 1982; 62: 498–506.

10.

Halle H, Chenoweth JM and Wambsganss MW. Flow-induced tube vibration thresholds in heat exchangers from shellside water tests. In: ASME symposium on flow-induced vibrations, New Orleans, LA, USA, 1984, Vol. 3, pp.17–32.

11.

Lumsden

Weaver

. The effect of fins on fluid elastic instability in in-line and rotated square tube arrays. J Press Vess Technol 2010; 132: 1–6.

12.

Wang

Weaver

. Fluid elastic instability in normal and parallel triangular arrays of finned tubes. J Press Vess Technol 2012; 134: 1–7.

13.

Desai

Pavitran

. Theoretical analysis of fluid elastic vibrations of finned tube arrays subjected to cross flow of water. J Vib Eng Technol 2016; 4: 21–29.

14.

Desai

Pavitran

. The effect of fin pitch on fluid elastic instability of tube arrays subjected to cross flow of water. J Instn Engrs (India): Ser C 2018; 99(1): 53–61.

15.

Desai

Pavitran

. Experimental investigation on vortex shedding and fluid elastic instability in finned tube arrays subjected to water cross flow. J Press Vess Technol 2017; 139: 051301-1–051301–10.

16.

Arshad

Khushnood

Ahmed

, et al. Effect of fin geometry on flow-induced vibration response of a finned tube in a tube bundle. J Appl Fluid Mech 2018; 11: 1143–1152.

17.

DYNAMIX 6503 Accelerometer, Data Sheet, General purpose instruments, France, 2010.

18.

DEWESoft 7.1.1 with DEWETRON Hardware and DAQP Charge Amplifier, User's manual, Austria, 2005.

19.

Mair

Jones

PDF

Palmer

RKW

. Vortex shedding from finned tubes. J Sound Vib 1975; 39: 293–296.

20.

Chung

Chu

I-C

. Fluid-elastic instability of rotated square tube array in an air-water two-phase cross flow. Nucl Eng Technol 2006; 38: 69–80.

21.

Tanaka

Takahara

Ohta

. Flow-induced vibration of tube arrays with various pitch-to-diameter ratios. J Press Vess Technol 1982; 104: 168–174.

22.

Pettigrew

Taylor

Janzen

, et al. Vibration behavior of rotated triangular tube bundles in two-phase cross flows. J Press Vess Technol 2002; 124: 144–153.

23.

Connors HJ Jr. Flow-induced vibrations of heat exchangers. New York: ASME, 1970.

24.

Pettigrew

Taylor

Fisher

, et al. Flow-induced vibration: recent findings and open questions. Nucl Eng Des 1998; 185: 249–276.

25.

Pettigrew

Taylor

. Vibration analysis of shell-and-tube heat exchangers: an overview—Part 1: flow, damping, fluid elastic instability. J Fluids Struct 2003; 18: 469–483.

26.

Al-Kaabi

Khulief

Said

. Prediction of flow-induced vibrations in tubular heat exchangers—part II: experimental investigation. J Press Vess Technol 2009; 131: 011302.