A Critical Review on Condensation Pressure Drop in Microchannels and Minichannels

Awad, M. M.; Dalkılıç, Ahmet Selim

doi:10.5772/60965

Cited by 4 publications

(2 citation statements)

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“…Heat transfer characteristics of condensation inside tubes have been studied extensively using experimental methods. Reviews of condensation in circular mini/micro‐channels relating to flow regimes, pressure drop, and heat transfer correlations were conducted by Cavallini et al and Awad et al Though the experimental setup can obtain flow regimes, heat transfer coefficients, and other parameters in the condensation process, the flow field, temperature distribution, and liquid film thicknesses are hard to get. Nowadays, with the development of computer equipment and numerical methods, the numerical methods to study condensation are increasingly drawing investigators’ attention.…”

Section: Introductionmentioning

confidence: 99%

Numerical study on heat transfer and pressure drop characteristics of R410A condensation in horizontal circular mini/micro‐tubes

Zhang

2016

Can J Chem Eng

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Heat transfer and pressure drop characteristics of condensation for R410A inside horizontal circular tubes with inner diameters ranging from 0.25–4 mm were investigated numerically. The effects of mass flux, vapour quality, tube diameters, and gravity on heat transfer and pressure drop characteristics were discussed. Liquid‐vapour interfaces and stream‐traces were also presented to give a better understanding of these effects on the condensing flow. Numerical heat transfer coefficients and pressure gradients fitted well with the empirical correlations. The results indicate that local heat transfer coefficients and pressure drop increase with increasing mass flux, vapour quality, and with decreasing tube diameters. A thin liquid film is formed at the upper part of the tube in mini‐channels, while a symmetrical annular flow is observed in microchannels. A vortex with its core lying at the bottom of the tube is formed in the tubes with an inner diameter of 4 mm, while the stream‐traces start from the z‐axis and point to the liquid‐vapour interface when dh is 0.25 mm. The gravity effect on heat transfer is important in larger tubes at lower vapour quality, where stratified flow may occur.

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Section: Introductionmentioning

confidence: 99%

Numerical study on heat transfer and pressure drop characteristics of R410A condensation in horizontal circular mini/micro‐tubes

Zhang

2016

Can J Chem Eng

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“…The problematic issues are stated as entrance, exit effects, quality effects and change in channel erosion mainly in open sources including contradictions in measurements. Extra information on two-phase flow in a single microchannel (air-water) [144][145][146][147][148][149][150][151], two-phase flow of refrigerant in multiport minichannel [44,[152][153][154][155][156], two-phase flow of refrigerant in short tube orifice [157][158][159][160][161][162][163][164], two-phase flow in a single microchannel (refrigerant) [165][166][167][168], micro channel heat sink with nanofluids [169][170], and general reviews on microchannel can be seen from authors previous studies [171][172][173][174][175], respectively.…”

Section: Surface Modification In Minichannels and Microchannelmentioning

confidence: 99%

A Review of Flow Boiling in Mini and Microchannel for Enhanced Geometries

Dalkılıç¹

2018

Journal of Thermal Engineering

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Flow boiling researches in enhanced geometries practiced recently have been summarized in this review. Classical approximations in macroscale flows have not applied to the flows with small hydraulic diameters, so, this subject has been paid attention by the researchers. Application areas of these structures are increasing continuously due to cooling need in small confined spaces. The related studies have been reviewed in a chronological manner and their parameters have been given in a table in order for the researchers to observe the scientific duration regarding the progresses on this subject. Almost all papers on this subject have been produced after 2000, therefore, this subject is considered as an actual one to improve and worth to study in the literature. This study can not only be evaluated as the beginning argument for the researchers involved in flow boiling process in mini and microchannel, but it also consists of new works on the investigated subject.

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