Tube Support Bar Thickness Gradient for Heat Exchanger Flow Uniformity
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Solution Overview
Problem
In heat exchangers, the constant number of spacers in tube bundle gaps leads to a non-uniform pressure drop across the radial direction, causing maldistribution of the refrigerant phase, with higher flow speeds and pressures on outer layers, resulting in phase distribution issues.
Innovation Solution
The spacers' thickness in the radial direction is varied, with thicker spacers closer to the core tube and thinner ones further out, maintaining a constant hydraulic diameter and reducing pressure drop variations across the tube bundle gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of spacers per tube bundle gap is kept constant, then the mechanical stability of tube layers is ensured, but the free cross-sectional area in inner tube bundle gaps is excessively reduced, causing non-uniform pressure drop and flow maldistribution
Solution Approach 1:
The patent applies local quality by varying the thickness of spacers based on their radial position. Inner tube bundle gaps receive thicker spacers while outer gaps receive thinner spacers, creating non-uniform local properties that compensate for the differing impact on free cross-sectional area. This local differentiation maintains mechanical stability throughout while ensuring uniform flow distribution across all gaps.
2Ease of operation
If thicker spacers are used in inner tube bundle gaps, then the free cross-sectional area reduction is compensated, but the spacer thickness varies radially requiring multiple spacer specifications
Solution Approach 1:
The patent implements parameter changes by systematically varying the spacer thickness parameter according to radial position. The thickness transitions from greater values in inner tube bundle gaps to smaller values in outer gaps, creating a gradient that compensates for the non-uniform geometry. This controlled parameter variation achieves flow uniformity while managing the complexity through a systematic design approach.
Data Source
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AI summary
The invention relates to a heat exchanger (1) for the indirect transfer of heat between a first and at least one second medium (M, M'), having a jacket space (I) for receiving the first medium (M), a core pipe (20) arranged in the jacket space (I), a pipe bundle (15) arranged in the jacket space (I), which bundle comprises a plurality of pipes (10) which are each wound around the core pipe (20) such that the pipe bundle (15) has a plurality of pipe layers arranged on top of each other (100, 101, 102, 103) which each comprise at least one pipe (10), a pipe bundle gap (200, 201, 202, 203) being present between all the adjacent pipe layers (100, 101; 101, 102;...) and a plurality of spacers (30) being arranged in each pipe bundle gap (200, 201, 202, 203) to support the pipe layers (100, 101, 102, 103). According to the invention, the spacers (30) each have a thickness (D) in the radial direction (R) of the pipe bundle (15), the thicknesses (D) of the spacers (30) of a first pipe bundle gap (200) each being greater than the thicknesses (D) of the spacers of a second pipe bundle gap (203), which lies further to the outside in the radial direction (R) of the pipe bundle (15) than the first pipe bundle gap (200).