Two-phase flow phenomena in full-scale reactor geometry

Mayinger, Franz; Weiss, Philipp; Wolfert, K.

doi:10.1016/0029-5493(93)90058-h

Cited by 60 publications

(51 citation statements)

References 2 publications

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“…It should be noted that the water level in the upper tank might relate to the dimensions of the inlet plenum of the upper tank. On the other hand, the CCFL characteristics obtained Figure 24 also compares CCFL data in the literature (Ohnuki, 1986, Mayinger et al, 1993 and the present study. Ohnuki (1986) examined the countercurrent flow using air-water and saturated steam-water systems with a 0.6 m length 45° inclined pipe and a 0.3 m length horizontal pipe with the inner diameter of 0.051 m, and a 0.6 m length 45° inclined pipe and a 0.4 m length horizontal pipe with the inner diameter of 0.076 m, in order to investigate the effects of length-to-diameter ratio in the horizontal pipe, the shape of the upper exit of the inclined riser, and the length of the inclined riser.…”

Section: (D) Oscillatory Flowsupporting

confidence: 84%

“…To improve reliability of the transient analysis, we need to understand and model the countercurrent flow in the hot leg. A number of experiments have been made about the countercurrent flow in the hot leg (Richter et al, 1978, Ohnuki, 1986, Ohnuki et al, 1988, Mayinger et al, 1993, Wongwises, 1996, Navarro, 2005, observations of detailed flow patterns in the hot leg, however, have not been reported. On the other hand, numerical simulations are a realistic way to evaluate the flow, because it is difficult to check the flow pattern in the actual PWR hot leg.…”

Section: Introductionmentioning

confidence: 99%

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Countercurrent Flow in a PWR Hot Leg under Reflux Condensation

Minami¹,

Murase²,

Tomiyama³

2011

Steam Generator Systems: Operational Reliability and Efficiency

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Section: (D) Oscillatory Flowsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Countercurrent Flow in a PWR Hot Leg under Reflux Condensation

Minami¹,

Murase²,

Tomiyama³

2011

Steam Generator Systems: Operational Reliability and Efficiency

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“…Figure 11 shows a comparison of CCFL data obtained by Mayinger et al 6) and the present study. The former experiments were carried out using saturated steam and water at 0.3 MPa in a real-scale apparatus simulating the hot leg.…”

Section: Discussionmentioning

confidence: 53%

“…Equations (5), (6), and (7) are for low, 18) intermediate, 19) and high 13) void fraction regions, respectively. The drift velocity is given by 20) V gj ¼ f1:4 À 0:4 expðÀ10ÞgðD…”

Section: Methodsmentioning

confidence: 99%

“…It is, therefore, necessary to understand the detailed characteristics of a countercurrent flow in the hot leg for developing a reliable model for predicting the flow. Although a number of experiments have been carried out on the countercurrent flow limitation, CCFL, in the hot leg, [3][4][5][6][7][8][9][10] two-phase flow patterns in the hot leg geometry have not been observed. Detailed knowledge on flow patterns in the inclined pipe and elbow in the hot leg under countercurrent flow conditions, therefore, has not been reported.…”

Section: Introductionmentioning

confidence: 99%

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Countercurrent Gas-Liquid Flow in a PWR Hot Leg under Reflux Cooling (II) Numerical Simulation of 1/15-Scale Air-Water Tests

Minami

Murase²,

Tomiyama

2010

Journal of Nuclear Science and Technology

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When reflux cooling is executed in the case of loss of residual heat removal systems under mid-loop operation of PWR, steam generated in the reactor core and water condensed in the steam generator may form a complicated countercurrent flow in the hot leg. Numerical simulations of air-water countercurrent flows in a 1/15-scale model of the hot leg are carried out in this study to examine the capability of predicting two-phase flow patterns and CCFL characteristics in the hot leg. A three-dimensional two-fluid model implemented in FLUENT6.3.26 is used in the simulations. Good agreements between measured and predicted flow patterns and CCFL characteristics are obtained by using an appropriate set of correlations for the interfacial friction coefficient in the momentum equation of the two-fluid model.

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Counter-current flow limitation velocity measured in annular narrow gaps formed between large diameter concentric pipes

Jeong

2008

Korean J. Chem. Eng.

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A two-phase flow configuration in which the gas phase flows upwards while the liquid phase flows downwards is referred to as a counter-current flow pattern. This flow configuration cannot be preserved if any flow rate exceeds a criterion known as the counter-current flow limitation (CCFL) or flooding. Since the CCFL is important to chemical engineers, it has long been studied via experimental and analytical approaches. Most of the previous CCFL experiments in annular channels have been carried out with a small diameter annulus and large gap-to-diameter ratio annulus. The present experiment examines the CCFL in narrow annular channels having gap sizes of 1, 2, 3, and 5 mm. The outer diameter of the annular passage is 500 mm. At a gap size of 1 mm, it was visually observed that a CCFL locally occurred in some region of the periphery while the other region remained in a counter-current flow configuration. The region under partial CCFL condition expanded with an increase in the air flow rate, finally reaching a global CCFL. The air flow rate for the global CCFL was roughly 15% larger than that for initiation of a partial CCFL. This difference in air flow rate between the initiation of a partial CCFL and the global CCFL was reduced as the gap size increased. When the gap size was 5 mm, the partial CCFL was not observed, but onset of flooding led to a global CCFL. Because of the existence of a transient period, the CCFL was experimentally defined as the situation where net water accumulation is sustained. The measured CCFL data are presented in the form of a Wallis' type correlation. Two length scales, hydraulic diameter and average circumference, were examined as the characteristic length scale. The average circumference appeared to better fit the experimental data, including results reported elsewhere. A new correlation using the average circumference as the characteristic length scale is suggested based on the experimental measurements of the present work and previous reports.

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Two-phase flow phenomena in full-scale reactor geometry

Cited by 60 publications

References 2 publications

Countercurrent Flow in a PWR Hot Leg under Reflux Condensation

Countercurrent Flow in a PWR Hot Leg under Reflux Condensation

Countercurrent Gas-Liquid Flow in a PWR Hot Leg under Reflux Cooling (II) Numerical Simulation of 1/15-Scale Air-Water Tests

Counter-current flow limitation velocity measured in annular narrow gaps formed between large diameter concentric pipes

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