Numerical study of condensation flow regimes in presence of non-condensable gas in minichannels

Lei, Yuchuan; Chen, Zhenqian

doi:10.1016/j.icheatmasstransfer.2019.04.001

Cited by 13 publications

(4 citation statements)

References 29 publications

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“…By using the numerical simulation method, the vapor condensation phenomena at each instant under the expected conditions can be easily obtained. The major numerical methods include traditional CFD methods, − molecular dynamics, − and the lattice Boltzmann (LB) method. , The LB method is a mesoscopic method, which has the properties of a simple algorithm, clear boundary, and efficient parallel computing capability. Owing to the superiority of the LB method, this method is widely used in the study of vapor condensation.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Vapor Condensation on a Hierarchical Microstructured Surface with a Phase-Change LB Method

Jin,

Mu,

et al. 2023

Ind. Eng. Chem. Res.

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Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Vapor Condensation on a Hierarchical Microstructured Surface with a Phase-Change LB Method

Jin,

Mu,

et al. 2023

Ind. Eng. Chem. Res.

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“…Nasrfard et al (2019) experimentally studied the condensation heat transfer of R141b in intermittent flow regime within a smooth horizontal tube. Lei and Chen (2019) conducted numerical research on flow regimes of R134a based on the VOF approach. Jige et al (2018) experimentally observed the two-phase flow characteristics of R32 in horizontal multiport rectangular minichannels with hydraulic diameters of 0.5 and 1.0 mm.…”

Section: Introductionmentioning

confidence: 99%

Flow Regimes and Transitions for Two-Phase Flow of R152a During Condensation in a Circular Minichannel

2021

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Two-phase flow regimes were experimentally investigated during the entire condensation process of refrigerant R152a in a circular glass minichannel. The inner and outer diameters of the test minichannel were 0.75 and 1.50 mm. The channel was 500 mm long to allow observation of all the two-phase flow regimes during the condensation process. The experiments used saturation temperatures from 30 to 50°C, a mass flux of 150 kg/(m2·s) and vapor qualities from 0 to 1. The annular, intermittent and bubbly flow regimes were observed for the experimental conditions in the study. The absence of the stratified flow regime shows that the gravitational effect is no longer dominant in the minichannel for these conditions. Vapor-liquid interfacial waves, liquid bridge formation and vapor core breakage were observed in the minichannel. Quantitative measurements of flow regime transition locations were carried out in the present study. The experiments also showed the effects of the saturation temperature and the cooling water mass flow rate on flow regime transitions. The results show that the annular flow range decreases and the intermittent and bubbly flow ranges change little with increasing saturation temperature. The cooling water mass flow rate ranging from 38.3 kg/h to 113.8 kg/h had little effect on the flow regime transitions.

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“…As computational science develops rapidly, numerical simulation has become one of the most effective tools in multiphase flows. Previously, condensation heat transfer was simulated using the macroscopic volume of fluid (VOF) method , and microscopic molecular dynamics method. , It is difficult for VOF method to capture phase interface according to Navier–Stokes equations when simulating the liquid–gas phase change process. In addition, due to the limitation of computer hardware and computational capacity, molecular dynamics can only be used to simulate the nucleation of nanodroplets but cannot predict the growth, coalescence, and departure behaviors of microdroplets.…”

Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Lattice Boltzmann Modeling of Condensation Heat Transfer on Downward-Facing Surfaces with Different Wettabilities

Wang

Chen

et al. 2020

Langmuir

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The model of vapor condensation heat transfer on downward-facing surfaces with different wettabilities is built by a two-dimensional (2D) lattice Boltzmann method. Dynamic evolution of condensate microdroplets on different wettability surfaces is simulated and the influence on heat transfer performance is analyzed. Moreover, the mechanism of a heterogeneous wettability surface enhancing condensation heat transfer is explored by investigating the condensate behaviors in the process of condensation. The numerical results indicate that as the contact angle of the homogeneous wettability surface increases, the initial nucleation time of the condensate is prolonged, while the departure time of the condensate is reduced significantly. The temperature adjacent to the gas−liquid interface, especially in the three-phase contact line region, is much higher than elsewhere due to the release of latent heat during condensation. Coalescence and detachment behaviors of condensate droplets cause the average heat flux to fluctuate locally with time. For the hybrid wettability surface, if the proportion of hydrophobic regions is small, the condensation heat transfer performance will be deteriorated. However, increasing the hydrophobic−hydrophilic ratio has a positive effect on enhancing heat transfer. It is found that a critical hydrophobic−hydrophilic ratio exists to optimize the heat transfer performance. For the gradient wettability surface, directional migration induced by capillary force facilitates the removal of condensate droplets, thereby enhancing the condensation heat transfer. Furthermore, a larger wetting gradient benefits to further improve the heat transfer performance. The results are valuable for optimally designing the heat transfer enhancement of vapor condensation on functionalized surfaces with heterogeneous wettability.

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Numerical study of condensation flow regimes in presence of non-condensable gas in minichannels

Cited by 13 publications

References 29 publications

Numerical Investigation of Vapor Condensation on a Hierarchical Microstructured Surface with a Phase-Change LB Method

Numerical Investigation of Vapor Condensation on a Hierarchical Microstructured Surface with a Phase-Change LB Method

Flow Regimes and Transitions for Two-Phase Flow of R152a During Condensation in a Circular Minichannel

Lattice Boltzmann Modeling of Condensation Heat Transfer on Downward-Facing Surfaces with Different Wettabilities

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