Falling film boiling of refrigerants over nanostructured and roughened tubes: Heat transfer, dryout and critical heat flux

Bock, Bradley D.; Bucci, Matteo; Markides, Christos N.; Thome, John R.; Meyer, Josua P.

doi:10.1016/j.ijheatmasstransfer.2020.120452

Cited by 18 publications

(4 citation statements)

References 55 publications

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“…All surfaces exhibited power-law relationships between the HTC and pressure, with similar HTCs at the lowest pressure which then diverged at higher pressures. In a later study [33], the same surfaces were investigated for falling-film boiling for the refrigerants R-134a and R-245a. It was found that the nanoFLUX and oxidized-copped surfaces reached critical dryout at the lowest heat fluxes (~20 kW m −2 ), and that falling-film enhancement ratios typically reached values of 0.8−1.3.…”

Section: Discussionmentioning

confidence: 99%

“…The tubes had an external diameter of 19.05 and a spcaing of 3.25 mm between them. The apparatus is outlined in more detail in Bock et al [33] and images captured during the study are shown in figure 9.…”

Section: Film Boilingmentioning

confidence: 99%

“…Bock et al [33] considered falling-film evaporators, which use surfaces constructed using three approaches: a nanostructured tube; copper-oxide through chemical oxidation and the commercial nanoFLUX approach-also discussed in §4.3.2 and outlined in Bock et al [29]. Here, however, the authors investigated the effect of varying the mass flow rate from 0 to 0.13 kg m −1 s −1 , Reynolds numbers from 0 to around 1500 to 2500, and heat fluxes from 20 to 100 kW m −2 .…”

Section: Film Boilingmentioning

confidence: 99%

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RS–DFID Africa capacity-building initiative programme grant: harnessing unsteady phase-change heat exchange in high-performance concentrated solar power systems

Winchester,

Maghrabi,

Markides

2024

Interface Focus.

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The Royal Society and UK Department for International Development supported a consortium of three universities across sub-Saharan Africa and Imperial College London with the aim of developing new knowledge on direct-steam-generation concentrated solar power (CSP) plants and supporting relevant capacity building across the Universities of Lagos, Mauritius and Pretoria. Key research findings from the programme include an improved flow-classification scheme for two-phase, liquid–liquid flows; testing of advanced surfaces with much-improved steady-state heat transfer performance—the commercial nanoFLUX surface showed up to 200% higher heat-transfer coefficients (HTCs) in pool boiling compared with other surfaces with R-134a/R-245fa; first-of-a-kind measurements of transient flow boiling HTCs, which were up to 30% lower in step perturbations than quasi-steady-state expectations in horizontal pipes with R-245fa; error estimation and corrections for laser-induced fluorescence (LIF) measurements, leading to the development of an adapted planar LIF technique with uncertainty <10% for local, instantaneous film thickness measurements in annular flows, and the application of such diagnostic methods to pool, falling-film and flow boiling in pipes; and predictions of an ~80% increase in the net present value of a case-study CSP plant when integrated with solid storage media.

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Section: Discussionmentioning

confidence: 99%

Section: Film Boilingmentioning

confidence: 99%

Section: Film Boilingmentioning

confidence: 99%

See 1 more Smart Citation

RS–DFID Africa capacity-building initiative programme grant: harnessing unsteady phase-change heat exchange in high-performance concentrated solar power systems

Winchester,

Maghrabi,

Markides

2024

Interface Focus.

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“…This group of authors have also carried out studies [131][132][133] on the effect of cocurrent and transverse vapor flows on the evaporation of R134a freon film flowing down a bundle of horizontal pipes. Interesting results have been reported recently [134] with comparison of enhancement of heat transfer during boiling and evaporation of freon falling films with the use of various methods of nano-modification of the heat-release surface, including the application of "nanoFLUXc" nanocoatings. Comparing experimental data, the authors of [134] show that the use of commercial coatings "nanoFLUXc" yields the best results in increasing the HTC and CHF relative to rough pipes and pipes with CuO nanocoatings.…”

Section: Heat Transfer Enhancement and Increase In Critical Heat Flux At Film Flowsmentioning

confidence: 99%

Development of Methods for Heat Transfer Enhancement During Nitrogen Boiling to Ensure Stabilization of HTS Devices

Павленко

Кузнецов

2021

J. Engin. Thermophys.

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The paper presents a brief analysis of current achievements and key issues in the field of heat transfer and critical heat flux enhancement during boiling of cryogenic liquids and freons under various heat release laws via micro-structuring of the heat-generating surface. A review of new experimental data on the efficiency of heat transfer and critical heat flux enhancement during pool boiling via new micro-structured capillary-porous coatings created by plasma sputtering and selective laser melting/sintering (3D printing) is presented. The results of analysis of the efficiency of heat transfer and critical heat flux during boiling on heat-generating surfaces with micro-textures of different shapes and micro-profiling created by micro-deforming cutting are presented. New results obtained during nitrogen boiling under various hydrodynamical conditions on the mechanisms of sharp increase in the rate of non-stationary cooling of plates with new structured capillary-porous or low-heat-conductivity coatings with certain parameters are discussed. New results on the degree of heat transfer enhancement during boiling of liquids on micro-structured surfaces modified by the method of micro-arc oxidation are presented.

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Refrigerant film flow and heat transfer characteristics on the elliptical tube under constant wall temperature

Wan

2022

Applied Thermal Engineering

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Falling film boiling of refrigerants over nanostructured and roughened tubes: Heat transfer, dryout and critical heat flux

Cited by 18 publications

References 55 publications

RS–DFID Africa capacity-building initiative programme grant: harnessing unsteady phase-change heat exchange in high-performance concentrated solar power systems

RS–DFID Africa capacity-building initiative programme grant: harnessing unsteady phase-change heat exchange in high-performance concentrated solar power systems

Development of Methods for Heat Transfer Enhancement During Nitrogen Boiling to Ensure Stabilization of HTS Devices

Refrigerant film flow and heat transfer characteristics on the elliptical tube under constant wall temperature

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