Variable-Diameter Tube Bundle Layout for Resonance Suppression
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Solution Overview
Problem
Tube bundle heat exchangers face challenges with resonance and noise due to wake oscillation and vortex shedding, which can lead to high cycle fatigue and undesirable noise levels, particularly in vibratory environments.
Innovation Solution
Implementing a configuration of tubes with varying diameters and specific spacing arrangements to disrupt vortex shedding and prevent resonance, enhancing thermal performance and extending the heat exchanger's useful life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If tubes with varying diameters and spacing are used, then resonance and noise are reduced, but device complexity increases
Solution Approach 1:
The patent applies local quality by varying tube diameters and spacings at different locations within the tube bundle. Specifically, the tube bundle includes tubes with different diameters (e.g., first diameter and second diameter) arranged in specific patterns, and spacings between adjacent tubes are varied (e.g., first spacing and second spacing). This local variation disrupts the coherence of vortex shedding across the bundle, preventing resonant conditions while maintaining effective heat exchange areas.
Solution Approach 2:
The patent employs asymmetry by deliberately creating non-uniform tube arrangements. The tube bundle contains asymmetric patterns where tubes of different diameters are positioned at different spacings, breaking the symmetry that would otherwise allow coherent vortex streets to form. This asymmetric configuration ensures that wake oscillations from individual tubes do not synchronize, thereby reducing resonance and noise generation.
2Ease of manufacture
If uniform tube spacing is used, then manufacturing is simplified, but vortex shedding coherence increases leading to resonance
Solution Approach 1:
Rather than using uniform spacing throughout, the patent implements local quality by varying spacings between adjacent tubes in different regions of the bundle. The configuration includes first spacings between certain adjacent tubes and second spacings between other adjacent tubes, where these spacings differ. This localized variation in spacing is sufficient to disrupt vortex coherence while remaining compatible with standard manufacturing processes.
Solution Approach 2:
The patent applies parameter changes by modifying the spacing parameter between tubes. Instead of maintaining a constant spacing value, the design incorporates multiple spacing values (first spacing, second spacing, etc.) within the tube bundle. This change in the spacing parameter disrupts the regularity of vortex shedding frequencies across the bundle, preventing resonance conditions while still allowing for practical manufacturing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The configuration of tubes with different diameters and spacings effectively disrupts vortex streets, reducing resonance and noise, improving thermal efficiency and extending the heat exchanger's lifespan.
Implementation Method 1
the oscillating wake can generate a force function on the tubes generating the wake as well as tubes downstream being hit with the incident wake
Implementation Method 2
wake frequency can be similar to the natural frequency of the tube, and resonance can occur which negatively impacts the high cycle fatigue (HCF) life
Implementation Method 3
Tube heat exchangers typically have a bundle of tubes which can include many rows of tubes in a cross-flow setup. The tubes carry one heat exchange medium and the other flows across the tubes
Data Source
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AI summary
A tube bundle heat exchanger (10) includes a flow space for a first heat exchange medium; and a plurality of heat exchange tubes (38, 40) for a second heat exchange medium, wherein the plurality of heat exchange tubes (38, 40) extends at least partially across the flow space, wherein the plurality of heat exchange tubes (38, 40) comprises at least a first plurality of tubes (38) having a first diameter and a second plurality of tubes (40) having a second diameter different from the first diameter.