Effects of fluid properties on CCFL characteristics at a vertical pipe lower end

Kusunoki, Takayoshi; Murase, Michio; Fujii, Yuki; Nozue, Takahiro; Hayashi, Kosuke; Hosokawa, Shigeo; Tomiyama, Akio

doi:10.1080/00223131.2014.990533

Cited by 22 publications

(13 citation statements)

References 12 publications

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“…The envelope can be obtained parametrically in terms of ∆P * . Kusunoki et al (2015) experimentally investigated the effects of the liquid viscosity on flow limitation at the sharp-edged lower end of a vertical pipe (CCFL-L). In this mode of flow limitation, the liquid flow is limited at the lower end of the pipe and some amount of liquid accumulated there is intermittently brought up by the gas flow (Govan et al, 1991;Kusunoki et al, 2015).…”

Section: Brief Review Of Ccfl Correlationsmentioning

confidence: 99%

“…Kusunoki et al (2015) experimentally investigated the effects of the liquid viscosity on flow limitation at the sharp-edged lower end of a vertical pipe (CCFL-L). In this mode of flow limitation, the liquid flow is limited at the lower end of the pipe and some amount of liquid accumulated there is intermittently brought up by the gas flow (Govan et al, 1991;Kusunoki et al, 2015). The following empirical correlation was proposed to take into account the effects of the gas and liquid viscosities on CCFL-L: Zapke and Kröger (1996) investigated the effects of the liquid viscosity and the surface tension σ on CCFL.…”

Section: Brief Review Of Ccfl Correlationsmentioning

confidence: 99%

“…In Kusunoki et al (2015), they obtained the CCFL characteristics for CCFL at the sharp-edged lower end of a vertical pipe (CCFL-L). In this section the fundamental functional form is reduced to the CCFL characteristics correlation for CCFL-L by making use of the CCFL data given in Kusunoki et al (2015). Figure 2 shows the CCFL characteristics of four two-phase systems, i.e.…”

Section: Ccfl Characteristics With Sharp-edged Lower Endmentioning

confidence: 99%

“…For example, CCFL may take place in the steam generator of a pressurized water reactor (PWR) during a reflux-cooling mode, and therefore, CCFL correlations are required to evaluate the flow rate of liquid flowing into the reactor core. Hence we have been investigating the CCFL characteristics in vertical pipes (Kusunoki et al, 2015(Kusunoki et al, , 2016Murase et al, 2016) and proposed some CCFL correlations (Kusunoki et al, 2015), which account for the effects of the fluid properties on the CCFL characteristics. The correlations were however obtained by a purely empirical manner.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Semi-empirical correlation for counter-current flow limitation at the upper or lower end of sharp-edged vertical pipes

Goda

Hayashi

Kirkland

et al. 2018

Nuclear Engineering and Design

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A semi-empirical correlation for CCFL (counter-current flow limitation) in vertical pipes was derived from one-dimensional momentum equations. Available correlations such as the empirical correlations proposed by Wallis (1969) and Zapke and Kröger (1996) can be deduced from the derived fundamental functional form of the semi-empirical correlation in limiting flow conditions. Comparisons between the semi-empirical correlation with available experimental data of CCFL taking place at the sharp-edged lower end of a vertical pipe showed that the correlation is applicable for various fluid properties and pipe diameters. The fundamental functional form of the correlation was also transformed so as to express the characteristics of CCFL occurring at the sharp-edged upper end of a vertical pipe. The present fundamental functional form of CCFL correlation is useful not only to express CCFL data but also to understand how relevant parameters play their roles in the CCFL characteristics.

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Section: Brief Review Of Ccfl Correlationsmentioning

confidence: 99%

Section: Brief Review Of Ccfl Correlationsmentioning

confidence: 99%

Section: Ccfl Characteristics With Sharp-edged Lower Endmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Semi-empirical correlation for counter-current flow limitation at the upper or lower end of sharp-edged vertical pipes

Goda

Hayashi

Kirkland

et al. 2018

Nuclear Engineering and Design

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“…シャープエッジ下端での CCFL(CCFL-L)を対象として空気・水実験を行い、Wallis 相関式において代表長さ w として直径 D を用いると CCFL 特性をよく整理できることを明らかにした [3]。また、蒸気・水実験 [4]と凝縮実験 [5]を行い、CCFL-L の相関式を導出した [5]。シャープエッジ上端での CCFL(CCFL-U)については、空気・水実験を行い w としてラプラス長さ L を用いるべきであることを明らかにし [6]、従来データ [7]を含めて CCFL-U の相関式を導出した [8]。また、前報 [9] では、上端・下端ともラウンドエッジでの従来データを用いて管内での CCFL(CCFL-P)について検討し、w ≈ D 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 1.E-03…”

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Effects of Fluid Properties on Countercurrent Flow Limitation in Vertical Pipes

Murase¹,

Kusunoki²,

Yamamoto³

et al. 2017

JAPANESE JOURNAL OF MULTIPHASE FLOW

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To evaluate effects of the diameter on countercurrent flow limitation (CCFL) in vertical pipes, in our previous study, we classified CCFL into CCFL-L at the sharp-edged lower end, CCFL-U at the sharp-edged upper end, and CCFL-P inside the vertical pipe with round-edged upper and lower ends, and we found that the characteristic length in the Wallis parameter,(where D and L respectively denote the diameter and the Laplace capillary length), is respectively β = 0, 1 and β ≈ 0.5 for CCFL-L, CCFL-U and CCFL-P. In this study, we evaluated effects of fluid properties on CCFL in vertical pipes by using existing CCFL data. The most effective fluid properties is the liquid viscosity and we selected the viscosity ratio of gas and liquid (μG/μL) as a dimensionless parameter. From effects of μG/μL on the slope m and constant C in the Wallis correlation, we classified three regions of large positive interrelations of m and C with μG/μL for small μL (room-temperature to high-temperature water), small interrelations of m and C with μG/μL for medium μL (low-concentration glycerol water solution), and the large negative interrelation of m with μG/μL for large μL (high-concentration glycerol water solution). We obtained exponent functions of μG/μL for m and C in the case of the small μL (room-temperature to high-temperature water) for CCFL-L and CCFL-U except CCFL-P without high-temperature CCFL data.

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An experimental study on gas–liquid two-phase countercurrent flow limitations of vertical pipes

Zeng²,

Shao³

et al. 2023

Experimental Thermal and Fluid Science

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Effects of fluid properties on CCFL characteristics at a vertical pipe lower end

Cited by 22 publications

References 12 publications

Semi-empirical correlation for counter-current flow limitation at the upper or lower end of sharp-edged vertical pipes

Semi-empirical correlation for counter-current flow limitation at the upper or lower end of sharp-edged vertical pipes

Effects of Fluid Properties on Countercurrent Flow Limitation in Vertical Pipes

An experimental study on gas–liquid two-phase countercurrent flow limitations of vertical pipes

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