Condensation in a Square Minichannel: Application of the VOF Method

Bortolin, Stefano; Riva, Enrico Da; Col, Davide Del

doi:10.1080/01457632.2013.812493

Cited by 90 publications

(32 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The same approach was also adopted in Bortolin et al [27], Kharangate et al [29], and Lee et al [16]. The basic equations for the continuity, momentum, energy, turbulence kinetic energy, and the specific dissipation rate are the same with those of single-phase flow as listed in Eq.…”

Section: Governing Equationsmentioning

confidence: 93%

“…3 and Eq.4 are based on the Lee [31] model which is widely adopted for condensation [16,17,[25][26][27][28][29] and evaporation [32,33] simulations.…”

Section: Governing Equationsmentioning

confidence: 99%

“…Based on this approach, Bortolin et al [27] studied the effect of channels shapes and Zhang et al [28] investigated the effect of saturation temperatures on the condensing flow.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The effect of gravity on R410A condensing flow in horizontal circular tubes

Zhang

et al. 2017

Numerical Heat Transfer, Part A: Applications

View full text Add to dashboard Cite

Heat transfer characteristics of R410A condensation in horizontal tubes with inner diameter of 3.78 mm under normal and reduced gravity are investigated numerically. The mass transfer model and numerical methods are validated by comparing the numerical heat transfer coefficients under normal gravity with the experimental work and empirical correlations. The results indicate that the heat transfer coefficients increase with increasing gravitational accelerations at a lower mass flux, while the difference of these under varing gravity is insignificant at a higher mass flux. The liquid film thickness decreases with increasing gravity at the top part of the tube at vapor quality x = 0.5 and 0.9, while the reverse is true for that at the tube bottom. The average liquid film thickness is nearly the same under different gravity accelerations at the same vapor quality and mass flux. The local heat transfer coefficients increase with increasing gravity at the top of the tube and decrease with increases in gravity at the bottom. The proportion of the thin liquid film region is important for the overall heat transfer coefficients for the condensing flow. A vortex with its core lying at the bottom of the tube is observed under normal gravity because of the combined effect of gravity and the mass sink at the liquid-vapor interface, while the stream traces point to the liquid-vapor interfaces under zero gravity. The mass transfer rate under zero gravity is much lower than that of normal gravity.

show abstract

Section: Governing Equationsmentioning

confidence: 93%

“…3 and Eq.4 are based on the Lee [31] model which is widely adopted for condensation [16,17,[25][26][27][28][29] and evaporation [32,33] simulations.…”

Section: Governing Equationsmentioning

confidence: 99%

See 1 more Smart Citation

The effect of gravity on R410A condensing flow in horizontal circular tubes

Zhang

et al. 2017

Numerical Heat Transfer, Part A: Applications

View full text Add to dashboard Cite

show abstract

“…For the steam flow condensation in tube, as well as the two-phase flow regime map, many investigations have been carried out, scholars have proposed many theoretical models about the steam flow condensation in tube, including VOF [20], Level set [21] and the interface tracking method [22][23][24][25][26][27][28]. Both VOF and the Level set model are based on the number of grids, so as a result, one can hardly obtain an accurate result when the film is thin enough.…”

Section: Condensate Film Development Inside Finned Flat Tubementioning

confidence: 99%

Anti-Freezing Mechanism Analysis of a Finned Flat Tube in an Air-Cooled Condenser

Guo

Cheng

et al. 2017

Energies

View full text Add to dashboard Cite

Abstract:In cold winter weather, the air-cooled condensers (ACCs) face serious freezing risks, especially with part load of the power generating unit. Therefore, it is of benefit to investigate the heat transfer process between the turbine exhaust steam and cooling air, by which the freezing mechanism of the finned tube bundles can be revealed. In this work, the flow and heat transfer models of the cooling air coupling with the circulating water, are developed and numerically simulated for the anti-freezing analysis on basis of the finned tube bundles of the condenser cell. The local air-side heat transfer coefficient, condensate film development, and non-condensable gas development are obtained and analyzed in detail. The results show that, the most freezing risk happens at the fin base due to the highest air-side cooling capacity, besides the windward velocity, ambient temperature and turbine back pressure all determine the freezing risk with the constant inlet flow rate of the non-condensable gas. Furthermore, increasing fin thickness and decreasing fan rotating speed are the most effective anti-freezing measures. Additionally, increasing turbine back pressure can also be adopted to avoid ACC freezing, however the adjustment of outlet steam-air flow is not recommended.

show abstract

“…Bortolin et al [6] presented a number of steady-state simulations of condensation of R134a at mass fluxes G = 400 kg m -2 s -1 and G = 800 kg m -2 s -1 inside a 1 mm square cross section minichannel. The gravity force has a minor effect on the liquid-vapour interface distribution in the square minichannel; the authors found that at these mass velocities, the heat transfer mechanism is dominated by shear stress and surface tension.…”

Section: Introductionmentioning

confidence: 99%

Minichannel condensation in downward, upward and horizontal configuration

Bortolato

Bortolin

Azzolin

2012

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

Abstract. An experimental investigation of condensation of R134a inside a single square cross section minichannel when varying the channel orientation is presented. Local heat transfer coefficients are measured in horizontal , vertical downflow and vertical upflow configurations. In the literature the number of local heat transfer coefficient values measured during condensation inside non-circular minichannels is rather limited and the effect of channel orientation during condensation is not much investigated. Some studies have been performed in inclined smooth tubes of larger diameters, where it was shown that the heat transfer coefficient is strongly affected by the liquid and vapour distributions. But minichannels may display a different behaviour because of the relative importance of shear stress, gravity and surface tension. The action of these forces may depend on operating conditions and orientation. In the present study, the channel is obtained from a copper rod and has a square cross section with 1.18 mm side length. Each corner has a curvature radius equal to 0.15 mm, which leads to a hydraulic diameter equal to 1.23 mm. Tests have been performed with R134a at 40°C saturation temperature, at mass velocity ranging between 100 and 790 kg m -2 s -1 . From the experimental results, the effect of the channel inclination when varying mass velocity and vapour quality is investigated.

show abstract

Condensation in a Square Minichannel: Application of the VOF Method

Cited by 90 publications

References 17 publications

The effect of gravity on R410A condensing flow in horizontal circular tubes

The effect of gravity on R410A condensing flow in horizontal circular tubes

Anti-Freezing Mechanism Analysis of a Finned Flat Tube in an Air-Cooled Condenser

Minichannel condensation in downward, upward and horizontal configuration

Contact Info

Product

Resources

About