Liquid Film Thickness in Vertical Circular Pipes Under Flooding Conditions at the Top End

Takaki, Tomohiro; Murase, Michio; Nishida, Koji; Goda, Raito; Shimamura, Takeyuki; Tomiyama, Akio

doi:10.1080/00295450.2019.1656521

Cited by 11 publications

(12 citation statements)

References 14 publications

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“…To cover a wide range of flow conditions, a comprehensive analysis was conducted by combining previous experimental data obtained from the developed flow region with the current results. These data [11,12,15,18,33,[36][37][38][39][40][41] were then compared with Nusselt's theoretical solution and two recently proposed empirical predictions [36,37]. The comparison, as shown in Fig.…”

Section: Film Thicknessmentioning

confidence: 99%

Experimental Study of Developing Free-Falling Annular Flow in a Large Scale Vertical Pipe

Xue¹,

Stewart²,

Kelly³

et al. 2023

Preprint

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Section: Film Thicknessmentioning

confidence: 99%

Experimental Study of Developing Free-Falling Annular Flow in a Large Scale Vertical Pipe

Xue¹,

Stewart²,

Kelly³

et al. 2023

Preprint

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“…They obtained fw and fi for RF from the measured data, and showed that fw cannot be neglected. Takaki et al [6,7] conducted air-water experiments using vertical pipes of D = 20 mm and 40 mm with a sharp-edged top end and a rounded bottom end (S/R), and measured CCFL at the top end (CCFL-U), dP/dz and αG. They evaluated liquid film thickness δf, fw and fi, and proposed correlations of δf, fw and fi for SF [7,8].…”

Section: Introductionmentioning

confidence: 99%

“…Takaki et al [10] carried out air-water experiments using a vertical pipe of D = 40 mm with the rounded top and bottom ends (R/R), and measured CCFL characteristics, dP/dz and αG. They obtained fw and fi, and derived a correlation for fw, which did not classify the flow state, using the previously measured data with D = 20 mm [5,6,9] and D = 40 mm [5,7,10].…”

Section: Introductionmentioning

confidence: 99%

“…The results were compared with those obtained with other combinations of the shapes (sharp-edged or rounded) at the top and bottom ends (R/S, S/R, and R/R). From the results of those experiments [5][6][7][9][10] and this experiment, we obtained a fi correlation for all flow states including SF and RF, and we evaluated the effect of the fi correlation on the prediction of αG.…”

Section: Introductionmentioning

confidence: 99%

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Gas-liquid Interfacial Friction Factor under Flooding Conditions in Vertical Pipes

TAKAKI,

YAMASHITA,

KURIMOTO

et al. 2023

JAPANESE JOURNAL OF MULTIPHASE FLOW

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In our previous studies, we carried out air-water counter-current flow experiments under flooding conditions in vertical pipes of 40 mm diameter with combinations of sharp-edged or rounded top and bottom ends to measure counter-current flow limitation (CCFL), pressure gradient dP/dz, and void fraction αG. We obtained the wall and interfacial friction factors, fw and fi, and proposed a correlation of fw. In the present study, we carried out similar experiments with sharp-edged top and bottom ends, and obtained fw and fi. We proposed a correlation of fi for all flow patterns including smooth film (SF) and rough film (RF) due to flooding at the top and bottom ends, respectively. By using the one-dimensional annular flow model and the proposed fw and fi correlations, we computed the liquid volume fraction αL,cal and compared it with the experimental data αL,exp. The computation gave two solutions of αL,cal for SF and RF, which agreed relatively well with the αL,exp values for SF and RF in the regions of low gas superficial velocity JG and high JG, respectively.

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“…フラッディングでの流動状態は鉛直管の上端及び下端の形状によって異なる[1]。Goda et al [5] は上端ラウンドエッジ・下端シャープエッジの鉛直管(RS: Round/Sharp)を用いて、Takaki et al [6,7] 2～4 に、 RR、 SR、 RS それぞれの Time-strip 画像を示す。RR(Fig. 2) 、SR(Fig.…”

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鉛直管内でのフラッディング状態における管内流動特性

Sano¹,

Goda²,

Hayashi³

et al. 2021

JAPANESE JOURNAL OF MULTIPHASE FLOW

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Counter-current flow limitation (CCFL), the void fraction α, the wall friction factor fw, and the interfacial friction factor fi depend on the shapes of the top and bottom ends of vertical pipes, i.e., the sharp top end and round bottom end (SR), round top end and sharp bottom end (RS), and round top and bottom ends (RR). We observed flow structures with a high-speed video camera and measured CCFL (the relationship between superficial velocities of up-flow gas and down-flow liquid), pressure gradient dP/dz, and α in a RR vertical pipe with the diameter of 20 mm, and working fluids of air and water under flooding conditions, and we obtained fw and fi by using the annular flow model. The feature of flow structures in RR was occurrence of disturbance waves inside the vertical pipe, while they mainly appear at the bottom end in SR and RS. The liquid volume fraction (1−α), dimensionless pressure gradient −(dP/dz) * , and fi in RR for rough film were the same as those for rough film in SR and RS. (1−α), −(dP/dz) * , fw, and fi in RR for smooth film were close to those in SR for smooth film but they were larger than those in SR due to larger falling liquid volume fraction. The upward velocity of disturbance waves was also discussed.

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Liquid Film Thickness in Vertical Circular Pipes Under Flooding Conditions at the Top End

Cited by 11 publications

References 14 publications

Experimental Study of Developing Free-Falling Annular Flow in a Large Scale Vertical Pipe

Experimental Study of Developing Free-Falling Annular Flow in a Large Scale Vertical Pipe

Gas-liquid Interfacial Friction Factor under Flooding Conditions in Vertical Pipes

鉛直管内でのフラッディング状態における管内流動特性

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