The influence of tripwires on the stability of tube bundles subjected to cross-flow

Book · Sun Dec 01 04:00:00 EST 1996

OSTI ID:403372

Romberg, O; Popp, K ^[1]

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1. Univ. of Hannover (Germany). Inst. of Mechanics

In heat exchanger tube arrays subjected to cross flow fluidelastic instability is a dangerous excitation mechanism. This paper reports on experimental investigations concerning the influence of disturbed flow on the stability behavior of normal and rotated triangular tube arrays of different pitch-to-diameter ratios as well as to in-line square arrays. The excitation is due to air cross flow in a wind tunnel. The experimental apparatus allows to measure the stability boundaries of fully flexible bundles as well as single flexibly mounted tubes with variable equilibrium position in otherwise fixed arrays as a function of the mass-damping parameter {delta}{sub r} and the reduced gap velocity V{sub r}. A disturbance of the flow channels between the tubes is achieved by application of thin Prandtl-tripwires with a diameter of 1/80 of tube diameter on the top and the bottom of each tube. This leads in most of the cases to a shift of the stability boundaries often to higher reduced gap velocities or even to stability in the entire parameter region, depending on the bundle configuration and equilibrium position. To understand these effects a simultaneous flow visualization based on the laser-light-sheet procedure has been carried out.

• OSTI ID: 403372
• Report Number(s): CONF-960706--; ISBN 0-7918-1775-X
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CROSSFLOW SYSTEMS
DESIGN
EXPERIMENTAL DATA
FLUID-STRUCTURE INTERACTIONS
HEAT EXCHANGERS
TURBULENCE