scholarly journals Erratum: “Air/Water Counter-Current Flow Experiments in a Model of the Hot Leg of a Pressurized Water Reactor” [Journal of Engineering for Gas Turbines and Power, 2009, 131(2), p. 022905]

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Christophe Vallée ◽  
Deendarlianto ◽  
Matthias Beyer ◽  
Dirk Lucas ◽  
Helmar Carl
Keyword(s):  
Gas Turbines ◽  
Current Flow ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor ◽  
Counter Current Flow ◽  
Counter Current ◽  
Flow Experiments

Experimental study on the air/water counter-current flow limitation in a model of the hot leg of a pressurized water reactor

2008 ◽  
Vol 238 (12) ◽  
pp. 3389-3402 ◽  
Author(s):  
Deendarlianto ◽  
Christophe Vallée ◽  
Dirk Lucas ◽  
Matthias Beyer ◽  
Heiko Pietruske ◽  
...  
Keyword(s):  
Experimental Study ◽  
Current Flow ◽  
Flow Limitation ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor ◽  
Counter Current Flow ◽  
Counter Current

scholarly journals FENOMENA ALIRAN UDARA-AIR BERLAWANAN ARAH PADA PIPA HORIZONTAL PADA L/D = 25 DAN L/D = 50

2020 ◽  
Vol 1 (1) ◽  
pp. 21-32
Author(s):  
Yulia Venti Yoanita ◽  
Sinung Tirtha ◽  
Eli Kumolosari ◽  
Bayu Gilang Purnomo
Keyword(s):  
Current Flow ◽  
Flow Limitation ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor ◽  
Counter Current Flow ◽  
Counter Current

Fenomena aliran sangat penting dalam rangka untuk mengetahui lebih lanjut tentang mekanisme Counter-Current Flow Limitation (CCFL) atau transisi dari aliran berlawanan arah menjadi aliran searah. Pola aliran stratified menjadi karakter yang awal dalam fenomena selanjutnya. Peningkatan kecepatan udara yang kecil akan sangat mempengaruhi pola aliran berubah. Gangguan antar muka akan selalu besar seiring dengan peningkatan kecepatan udara. Alat yang digunakan untuk penelitian ini sama dengan salah satu komponen pada Pressurized Water Reactor (PWR) yang disebut hot leg dengan perbandingan 1/30. Hot leg adalah bagian pipa yang diamati dalam penelitian ini. Dimensi dari hotleg berupa pipa mendatar, pipa miring dan belokan yang terpasang menjadi satu dalam suatu saluran pokok PWR. Pada penelitian ini simulator hot leg dibuat dengan L/D = 50 dan L/D = 25. Simulator ini terdiri dari pipa horizontal, belokan dan miring dengan sudut kemiringan 50o. Visual yang dapat diamati dalam saluran hotleg, sehingga fenomena-fenomena yang terjadi dapat diamati secara rinci. Pengamatan visual dilakukan dengan menggunakan kamera berkecepatan tinggi. Sehingga data yang didapat dan diolah didapatkan secara valid. Hasil pengamatan yang diperoleh adalah pola aliran yang terjadi pada pipa horizontal. Penambahan kecepatan udara menyebabkan cepat terjadinya perubahan pola aliran pada L/D = 50. Sedangkan, pada L/D = 25 perubahan pola aliran dapat terjadi dengan kecepatan udara yang besar.

Air/Water Counter-Current Flow Experiments in a Model of the Hot Leg of a Pressurized Water Reactor

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Christophe Vallée ◽  
Deendarlianto ◽  
Matthias Beyer ◽  
Dirk Lucas ◽  
Helmar Carl
Keyword(s):  
Steam Generator ◽  
Pressure Vessel ◽  
Test Section ◽  
Current Flow ◽  
Flow Limitation ◽  
Two Phase ◽  
Pressurized Water ◽  
Counter Current Flow ◽  
Counter Current ◽  
Inlet Chamber

Different scenarios of small break loss of coolant accident for pressurized water reactors (PWRs) lead to the reflux-condenser mode in which steam enters the hot leg from the reactor pressure vessel (RPV) and condenses in the steam generator. A limitation of the condensate backflow toward the RPV by the steam flowing in counter current could affect the core cooling and must be prevented. The simulation of counter-current flow limitation conditions, which is dominated by 3D effects, requires the use of a computational fluid dynamics (CFD) approach. These numerical methods are not yet mature, so dedicated experimental data are needed for validation purposes. In order to investigate the two-phase flow behavior in a complex reactor-typical geometry and to supply suitable data for CFD code validation, the “hot leg model” was built at Forschungszentrum Dresden-Rossendorf (FZD). This setup is devoted to optical measurement techniques, and therefore, a flat test-section design was chosen with a width of 50 mm. The test section outlines represent the hot leg of a German Konvoi PWR at a scale of 1:3 (i.e., 250 mm channel height). The test section is mounted between two separators, one simulating the RPV and the other is connected to the steam generator inlet chamber. The hot leg model is operated under pressure equilibrium in the pressure vessel of the TOPFLOW facility of FZD. The air/water experiments presented in this article focus on the flow structure observed in the region of the riser and of the steam generator inlet chamber at room temperature and pressures up to 3 bar. The performed high-speed observations show the evolution of the stratified interface and the distribution of the two-phase mixture (droplets and bubbles). The counter-current flow limitation was quantified using the variation in the water levels measured in the separators. A confrontation with the images indicates that the initiation of flooding coincides with the reversal of the flow in the horizontal part of the hot leg. Afterward, bigger waves are generated, which develop to slugs. Furthermore, the flooding points obtained from the experiments were compared with empirical correlations available in literature. A good overall agreement was obtained, while the zero penetration was found at lower values of the gaseous Wallis parameter compared with previous work. This deviation can be attributed to the rectangular cross section of the hot leg model.

Interfacial behavior of the air-water counter-current two-phase flow in a 1/30 scale-down of pressurized water reactor (PWR) hot leg

2018 ◽  
Vol 116 ◽  
pp. 376-387
Author(s):  
Apip Badarudin ◽  
Andriyanto Setyawan ◽  
Okto Dinaryanto ◽  
Arif Widyatama ◽  
Indarto ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Phase Flow ◽  
Pressurized Water Reactor ◽  
Interfacial Behavior ◽  
Two Phase ◽  
Pressurized Water ◽  
Water Reactor ◽  
Scale Down ◽  
Counter Current

Experiments on Air-Water Countercurrent Flow in a Rectangular Duct Simulating PWR Hot Leg

2008 ◽  
Author(s):  
Noritoshi Minami ◽  
Daisuke Nishiwaki ◽  
Hironobu Kataoka ◽  
Akio Tomiyama ◽  
Shigeo Hosokawa ◽  
...  
Keyword(s):  
Current Flow ◽  
Heat Removal ◽  
Flow Patterns ◽  
Countercurrent Flow ◽  
Rectangular Duct ◽  
Horizontal Section ◽  
Pressurized Water ◽  
Mist Flow ◽  
Counter Current Flow ◽  
Counter Current

In the case of loss of the residual heat removal system under mid-loop operation during shutdown of the pressurized water reactor (PWR) plant, steam generated in a reactor core and condensed water in a steam generator (SG) form a countercurrent flow in a hot leg. In this study, in order to improve a counter-current flow model of a transient analysis code, experiments were conducted using a scale-down model of the PWR hot leg, and flow patterns and counter-current flow limitation (CCFL) characteristics were measured. A rectangular duct, whose height is about 1/5th of the hot leg diameter, was used to simulate the hot leg, and air and water at atmospheric pressure and room temperature were used for gas and liquid phases. In the horizontal section, as air flow rate QG increases, the flow pattern transits from a stratified flow to wavy flow, and then wavy to wavy-mist flow. When the latter transition takes place, water flow from the horizontal duct to the lower tank is to be restricted. Flow patterns in the elbow section are the same as those in the horizontal section. Wavy flow is not formed in the inclined section, where the transition to wavy-mist flow occurs due to the inflow of wavy-mist flow generated in the horizontal section. Flow patterns in the elbow and inclined section are strongly affected by those in the horizontal section. CCFL characteristics are well correlated with the Wallis-type correlation, and the onset of CCFL well corresponds to the transition from wavy flow to wavy-mist flow.

Air/Water Counter-Current Flow Experiments in a Model of the Hot Leg of a Pressurised Water Reactor

2008 ◽  
Author(s):  
Christophe Valle´e ◽  
Deendarlianto ◽  
Matthias Beyer ◽  
Dirk Lucas ◽  
Helmar Carl
Keyword(s):  
Steam Generator ◽  
Pressure Vessel ◽  
Test Section ◽  
Current Flow ◽  
Two Phase ◽  
Counter Current Flow ◽  
Counter Current ◽  
Flow Experiments ◽  
Inlet Chamber ◽  
Reactor Pressure

Different scenarios of small break Loss of Coolant Accident (LOCA) for pressurised water reactors (PWR) lead to the reflux-condenser mode in which steam enters the hot leg from the reactor pressure vessel (RPV) and condenses in the steam generator. A part of the condensate flows back towards the RPV in counter current to the steam. During the reflux-condenser mode, a counter-current flow limitation (CCFL) must be prevented because this would limit the core cooling. The simulation of CCFL conditions, which is dominated by 3D effects, requires the use of a computational fluid dynamics (CFD) approach. These methods are not yet mature and have to be validated before they can be applied to nuclear reactor safety. Therefore, dedicated experimental data is needed with high resolution in space and time. In order to investigate the two-phase flow behaviour in a complex reactor-typical geometry and to supply suitable data for CFD code validation, the “hot leg model” was built at Forschungszentrum Dresden-Rossendorf (FZD). This setup is devoted to optical measurement techniques, therefore, a flat test-section design was chosen with a width of 50 mm. The test-section outlines represent the hot leg of a German Konvoi PWR at a scale of 1:3, which corresponds to a channel height of 250 mm in the straight part of the hot leg. The test-section is mounted between two separators, one simulating the reactor pressure vessel and the other is connected to the steam generator inlet chamber. This allows to perform co-current as well as counter-current flow experiments. Moreover, the hot leg model is built in the pressure vessel of the TOPFLOW facility of FZD, which is used to perform high-pressure experiments under pressure equilibrium with the inside atmosphere of the vessel. Therefore, the test section can be designed with thin materials and equipped with big size windows like in the hot leg model. The presented air/water experiments focus on the flow structure observed in the region of the riser and of the steam generator inlet chamber at room temperature and pressures up to 3 bars. The performed high-speed observations show the evolution of the stratified interface and the distribution of the two-phase mixture (droplet and bubbles). Counter-current flow limitation, or the onset of flooding, was found by analysing the water levels measured in the separators. A confrontation with the images indicates that the initiation of flooding coincides with the reversal of the flow in the horizontal part of the hot leg due to high air velocities. Afterwards, bigger waves are generated, which develop to slugs. Furthermore, the CCFL data was compared with similar experiments and empirical correlations available in the literature. The agreement of the CCFL curve is good and indicate that the data is relevant for CFD validation purposes. The zero penetration was found at lower values of the Wallis parameter than in most of the previous work, which can be attributed to the rectangular geometry of the hot leg model.

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