Optimization to the tube–fin contact status of the tube expansion process

Ding, Tao; Li, Dayong; Peng, Yinghong

doi:10.1016/j.jmatprotec.2010.11.010

Cited by 12 publications

(5 citation statements)

References 8 publications

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“…In 2006, Cheng et al [9] studied the relationship between the contact gap and the expansion mould and analysed the influence law of three mould structures (spiral, forward, and backward) on the contact gap. In 2010 and 2011, Tang et al [10,11] used finite element and test methods to study the contact state of the mechanical expansion of tube-fin heat exchangers. The influence of the expansion rate of the heat exchange tube on the contact gap was analysed.…”

Section: Introductionmentioning

confidence: 99%

Hydraulic Expansion Joint Contact State of Heat Exchanger Based on New Contact Area Measurement Method

Zhang,

Liu,

et al. 2023

Materials

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The contact state of a seamless internal threaded copper tube and an aluminium foil fin not only affects the heat transfer efficiency of a tube–fin heat exchanger but also seriously affects its service life. In this study, hydraulic expansion technology was used to connect the copper tube with an internal thread with a 7 mm diameter to the fin of the heat exchanger. The influence of the expansion pressure and pressure holding time on the contact state was analysed through experiments and finite element simulation, and the variation law of the two on the contact state was obtained. The contact state was characterised by the contact gap and contact area. In order to obtain the specific contact area value, a new method of measuring the contact area was developed to reveal the variation in contact area between the copper tube and the fin after expansion. The results show that the contact gap decreases with an increase in expansion pressure, while the pressure holding time remains the same. The contact area increases with an increase in expansion pressure, and the rate of increase slows. When the expansion pressure is 18 MPa, the average contact gap is approximately 0.018 mm. When the expansion pressure reaches 16 MPa, the contact area ratio is 91.0%. When the expansion pressure increases to 18 MPa, the contact area ratio only increases by approximately 0.6%. Compared with the influence of the expansion pressure on the increase in contact area, the influence of the pressure holding time on the contact area is lower.

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Section: Introductionmentioning

confidence: 99%

Hydraulic Expansion Joint Contact State of Heat Exchanger Based on New Contact Area Measurement Method

Zhang,

Liu,

et al. 2023

Materials

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“…In Tang et al, 23 they investigated the influence of the groove shape of the tubes on the quality of the forming (expansion) process. In Tang et al, 24 they optimised the expansion process, developing a method based on numerical simulations and experimental tests. For example, they focussed on the shape of the fin collar to increase the contact surface between the tube and the fin.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the mechanical expansion process of thin-walled tubes for air heat-exchanger production

Scattina

Avalle

2022

Proceedings of the Institution of Mechanical Engineers, Part B:

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Finned tube air heat-exchangers are built by joining the tubes to the fins by various techniques. A technique mostly used for large heat-exchangers consists of fitting the tubes into the holes of the fins by expanding the tubes using a mechanical process. The expansion is achieved by inserting an ogive of a larger diameter into the tube. The intimate contact of tubes and fins due to the press fitting ensures the proper thermal connection. This work tries to describe an experimental-numerical procedure useful to study and predict the mechanical process and the process parameters. The procedure, based on material properties obtained from tensile tests and the use of the inverse method to identify the material parameters, is based on bi-dimensional finite element (FE) models used to simulate the expansion process. The FE model is then used for process optimisation regarding such parameters as the ogive shape and ogive sizes, friction coefficient and speed of insertion of the ogive into the tube. Indeed, size and shape uncertainties strongly influence the process parameters and the process quality, as well as the heat-exchanger efficiency. The use of numerical models was proven highly effective in predicting and optimising the process by quickly analysing the influencing factors and optimising the production.

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“…The most common type of heat exchanger used in gas-fired water heater was the copper tube-fin compact heat exchanger, what consists of water tube banks and gas side fins [1]. Many individual fins were connected to the tubes by the tube expansion process [2,3]. Nevertheless, there have several disadvantages to this structure.…”

Section: Introductionmentioning

confidence: 99%

Structural parameters study on stainless-steel flat-tube heat exchangers with corrugated fins

Gao

Wang²,

Cui

2020

THERM SCI

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A stainless steel corrugated fins and flat-tube heat exchanger is designed, which has a plate-fin structure. To optimize the structural parameters of this exchanger, including corrugation angle, corrugation pitch and fin length, 3-D simulation model and test were proposed. The numerical results indicated that the corrugation angle significantly affects both on heat transfer performance and pressure drop. The fin with angle, A = 0~20°, have demonstrated the higher heat transfer efficiency, lesser gas condensation, lower pressure drop, higher outlet flue gas temperature in low T region, and no exceeding the distortion temperature in high T region. Corrugation pitch and fin length influence thermal and hydraulic characteristics, outlet flue gas temperature, and fin temperature. To improve heat transfer performance, and reduce the fin temperature in high T region and ease gas condensation in low T region, smaller corrugation pitch and shorter fin length were recommended in the low T region, whereas higher values were more reasonable in high T region. Noticeably, the heat transfer and flow characteristics were better in the high T region than the low T region. Therefore, higher priority should be given to the structural optimization in the high T region in order to increase the heat transfer enhancement.

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Optimization to the tube–fin contact status of the tube expansion process

Cited by 12 publications

References 8 publications

Hydraulic Expansion Joint Contact State of Heat Exchanger Based on New Contact Area Measurement Method

Hydraulic Expansion Joint Contact State of Heat Exchanger Based on New Contact Area Measurement Method

Analysis of the mechanical expansion process of thin-walled tubes for air heat-exchanger production

Structural parameters study on stainless-steel flat-tube heat exchangers with corrugated fins

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