Convective condensation in three enhanced tubes with different surface modifications

Li, Wei; Tang, Weiyu; Chen, Jingxiang; Zhu, Hua; Kukulka, David J.; He, Yan; Sun, Zhigang; Du, Jincai; Zhang, Bin

doi:10.1016/j.expthermflusci.2018.04.011

Cited by 25 publications

(6 citation statements)

References 29 publications

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“…A detailed description of the test apparatus with an uncertainty analysis is provided in Li et al [9] and Wu et al [19]. Figure 1a shows the test apparatus made up of a refrigeration circuit and cooling water circuit.…”

Section: Methodsmentioning

confidence: 99%

“…Li et al [8] studied tube-side condensation and evaporation characteristics of structured 3D enhanced tubes. A similar experimental investigation has been performed by Li et al [9] in order to evaluate the condensation of novel EHT enhanced tubes. Their results indicate the 1EHT tube exhibited the highest performance factors.…”

Section: Introductionmentioning

confidence: 95%

“…Performance enhancement of 54 to 64% is demonstrated for the 1EHT tube; however, the performance of a smooth tube is better than a 1EHT tube under evaporating conditions. Li et al [9] evaluated micro fin and 3D tubes in order to determine intube condensation characteristics. They found that the HTC of a copper herringbone tube was up to 2.2 times higher than the HTC of a smooth tube; while the performance increase of the 1EHT tube was up to 1.65 times higher.…”

Section: Introductionmentioning

confidence: 99%

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An Experimental Study of In-Tube Condensation and Evaporation Using Enhanced Heat Transfer (EHT) Tubes

et al. 2021

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A study was carried out to determine in-tube evaporation and condensation performance of enhanced heat transfer tubes (EHT) using R410A, with the results being compared to a plain tube. The test tubes considered in the evaluation include: plain, herringbone (HB) and spiral (HX) microgrooves, herringbone dimple (HB/D), and hydrophobic herringbone (HB/HY). Experiments to evaluate the condensation were conducted at a saturation of 318 K, and at 279 K for evaporation. Mass flux (G) ranged between 40 to 230 kg m−2s−1. Condensed vapor mass decreased from 0.8 to 0.2; and the mass of vaporized vapor increases from 0.2 to 0.8; heat flux increased with G. Inlet and outlet two-phase flow patterns at 200 kg m−2s−1 were recorded and analyzed. Enhanced tube heat transfer condensation performance (compared to a plain tube) increased in the range from 40% to 73%. The largest heat transfer increase is produced by the herringbone–dimple tube (HB/D). In addition to providing drainage, the herringbone groove also helps to lift the accumulated condensate to wet the surrounding wall. Evaporation thermal performance of the enhanced tubes are from 4% to 46% larger than that of smooth tube with the best performance being in the hydrophobic herringbone tube (HB/HY). This enhancement can be attributed to an increase in the number of nucleation sites and a larger heat transfer surface area. Evaporation and condensation correlations for heat transfer in smooth tubes is discussed and compared.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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An Experimental Study of In-Tube Condensation and Evaporation Using Enhanced Heat Transfer (EHT) Tubes

et al. 2021

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“…The heat input of the test section varied with the temperature of the thermostat bath and the water flow rates; in order to achieve the desired vapor quality, the refrigerant was heated or cooled in the test section. Additional details of the test apparatus can be obtained from Li et al [21]. Figure 2b illustrates the test section employed in this work; the test section was a double-pipe heat exchanger with an effective heat length of 2 m. In this study, tubes with an inner diameter of 25 mm and 26 mm were employed as the outer tube in order to investigate the effect of annulus width; the tested tubes were used as the inner tube of the heat exchanger.…”

Section: Test Conditionsmentioning

confidence: 99%

Comparison of the Evaporation and Condensation Heat Transfer Coefficients on the External Surface of Tubes in the Annulus of a Tube-in-Tube Heat Exchanger

Tang

Kukulka

et al. 2020

Energies

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An experimental study was carried out to explore the heat transfer characteristics on the outside of smooth and enhanced tubes, during evaporation and condensation of R134A in the annulus of a tube-in-tube heat exchanger. The three-dimensional enhanced surface tube consisted of primary enhancement patterns and secondary patterns; results were compared to the performance of an equivalent smooth tube. The equivalent external diameter of the inside horizontal copper tubes used in this study was 19.05 mm, while the outer tube varied in size, allowing a comparison of heat transfer for different annulus dimensions. Tests were conducted with a fixed inlet/outlet vapor quality and a constant saturation temperature for varied mass velocities in the range of 30 to 100 kg/(m2∙s). For condensation, the ratio of heat transfer coefficient enhancement (enhanced tube/ smooth tube) was up to 1.78; this can be attributed to the turbulence increase, as well as liquid film re-distribution, produced from the dimples. Furthermore, the condensation heat transfer coefficient increased rapidly with increasing mass flux. For flow boiling in the annulus between the 1EHT tube and outer tube, the heat transfer coefficient during boiling was 11–36% higher when compared to the smooth tube at xave = 0.35, while the performance of the 1EHT tube was not as good as the smooth tube at xave = 0.5. The heat transfer deterioration can be explained by decreased effective nucleate flow boiling heat transfer area and the flow pattern transition between a slug/wavy-stratified flow to wavy-stratified flow.

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“…Research also revealed that the simultaneous drop-wise and film-wise condensations had a higher heat transfer coefficient compared to the single drop-wise or film-wise mode. Li et al (2018a) investigated the performance of different enhanced surfaces for the in-tube convective condensation of R410a.…”

Section: Optimisation Of Operating Conditionsmentioning

confidence: 99%

Thermal Energy Processes in Direct Steam Generation Solar Systems: Boiling, Condensation and Energy Storage – A Review

et al. 2019

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Convective condensation in three enhanced tubes with different surface modifications

Cited by 25 publications

References 29 publications

An Experimental Study of In-Tube Condensation and Evaporation Using Enhanced Heat Transfer (EHT) Tubes

An Experimental Study of In-Tube Condensation and Evaporation Using Enhanced Heat Transfer (EHT) Tubes

Comparison of the Evaporation and Condensation Heat Transfer Coefficients on the External Surface of Tubes in the Annulus of a Tube-in-Tube Heat Exchanger

Thermal Energy Processes in Direct Steam Generation Solar Systems: Boiling, Condensation and Energy Storage – A Review

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