Visualization study of steam condensation in triangular microchannels

Chen, Yongping; Wu, Ruey-Shyang; Shi, Mingheng; Wu, Jiafeng; Peterson, G. P.

doi:10.1016/j.ijheatmasstransfer.2009.04.034

Cited by 48 publications

(20 citation statements)

References 28 publications

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“…Visualization and digital image analysis has enabled investigation of flow condensation and underlying flow mechanisms which affect condensation heat transfer. Chen et al [55] investigated steam condensation in triangular microchannel with hydraulic diameters of 100 lm and 250 lm and observed droplet, annular injection, and slug-bubbly flow. Increased mass flux was shown to enhance condensation heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Combined Visualization and Heat Transfer Measurements for Steam Flow Condensation in Hydrophilic and Hydrophobic Mini-Gaps

Chu

Derby

2016

Journal of Heat Transfer

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Condensation enhancement was investigated for flow condensation in mini-channels. Simultaneous flow visualization and heat transfer experiments were conducted in 0.952-mm diameter mini-gaps. An open loop steam apparatus was constructed for a mass flux range of 50-100 kg/m 2 s and steam quality range of 0.2-0.8, and validated with single-phase experiments. Filmwise condensation was observed in the hydrophilic minigap; pressure drop and heat transfer coefficients were compared to the (Kim and Mudawar, 2013, "Universal Approach to Predicting Heat Transfer Coefficient for Condensing Mini/Micro-Channel Flow," Int. J. Heat Mass Transfer, 56(1-2), pp. 238-250) correlation and prediction was very good; the mean absolute error (MAE) was 20.2%. Dropwise condensation was observed in the hydrophobic mini-gap, and periodic cycles of droplet nucleation, coalescence, and departure were found at all mass fluxes. Snapshots of six typical sweeping cycles were presented, including integrated flow visualization quantitative and qualitative results combined with heat transfer coefficients. With a fixed average steam quality ( x ¼ 0.42), increasing mass flux from 50 to 75 to 100 kg/m 2 s consequently reduced average sweeping periods from 28 to 23 to 17 ms and reduced droplet departure diameters from 13.7 to 12.9 to 10.3 lm, respectively. For these cases, condensation heat transfer coefficients increased from 154,700 to 176,500 to 194,800 W/m 2 K at mass fluxes of 50, 75, and 100 kg/m 2 s, respectively. Increased mass fluxes and steam quality reduced sweeping periods and droplet departure diameters, thereby reducing liquid thickness and increasing heat transfer coefficients.

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Section: Introductionmentioning

confidence: 99%

Combined Visualization and Heat Transfer Measurements for Steam Flow Condensation in Hydrophilic and Hydrophobic Mini-Gaps

Chu

Derby

2016

Journal of Heat Transfer

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“…In addition, Zhang et al [15,16] also investigated the bubble emission and the multichannel effect of condensation in rectangular microchannels. Recently, the flow pattern and heat transfer characteristics of condensation in triangular microchannels were detailed in a study by Chen et al [17]. The correlations of injection location and frequency with the inlet vapor Reynolds number, condensate Weber number, and hydraulic diameter were acquired based on the experimental data.…”

Section: Introductionmentioning

confidence: 99%

Visualization study of steam condensation in wide rectangular silicon microchannels

Shi

Chen

et al. 2010

International Journal of Thermal Sciences

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“…Chen et al [5] performed a visualization experiment to investigate the steam condensation in triangular microchannels with hydraulic diameters of 100 and 250 m. The experimental results indicated that the droplet, annular, injection, and slug-bubbly flows are the dominant flow patterns during steam condensation in microchannels. In addition, they proposed the correlations for injection location, injection frequency, and condensation Nusselt number.…”

Section: Introductionmentioning

confidence: 99%

Two-Phase Flow and Heat Transfer during Steam Condensation in a Converging Microchannel with Different Convergence Angles

Chang

Pan

2013

Advances in Mechanical Engineering

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The present study experimentally investigates the effect of convergence angle of microchannel on two-phase flow and heat transfer during steam condensation. Three condensation regimes, from the inlet to the outlet, are identified: mist/annular flow, injection flow, and slug-bubbly flow. Flow pattern maps are constructed using superficial vapor and liquid velocities as the coordinates, wherein relatively distinct boundaries between the flow patterns can be identified. The experimental results show that the condensation heat flux increases with an increase in the convergence angle and/or the steam mass flux at a given coolant flow rate but decreases with an increase in the coolant flow rate at a given steam mass flux. The results further demonstrate that the local condensation heat transfer coefficient in the mist/annular flow region is much higher than that in other condensation regimes. Moreover, the local condensation heat transfer coefficient in the mist/annular flow and injection flow region decreases with an increase in the convergence angle.

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Visualization study of steam condensation in triangular microchannels

Cited by 48 publications

References 28 publications

Combined Visualization and Heat Transfer Measurements for Steam Flow Condensation in Hydrophilic and Hydrophobic Mini-Gaps

Combined Visualization and Heat Transfer Measurements for Steam Flow Condensation in Hydrophilic and Hydrophobic Mini-Gaps

Visualization study of steam condensation in wide rectangular silicon microchannels

Two-Phase Flow and Heat Transfer during Steam Condensation in a Converging Microchannel with Different Convergence Angles

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