scholarly journals Countercurrent Air-Water Flow in a Scale-Down Model of a Pressurizer Surge Line

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Takashi Futatsugi ◽  
Chihiro Yanagi ◽  
Michio Murase ◽  
Shigeo Hosokawa ◽  
Akio Tomiyama
Keyword(s):  
Inclination Angle ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Flow Direction ◽  
Reactor Core ◽  
Scale Model ◽  
Countercurrent Flow ◽  
Flow Limitation ◽  
Scale Down ◽  
Surge Line

Steam generated in a reactor core and water condensed in a pressurizer form a countercurrent flow in a surge line between a hot leg and the pressurizer during reflux cooling. Characteristics of countercurrent flow limitation (CCFL) in a 1/10-scale model of the surge line were measured using air and water at atmospheric pressure and room temperature. The experimental results show that CCFL takes place at three different locations, that is, at the upper junction, in the surge line, and at the lower junction, and its characteristics are governed by the most dominating flow limitation among the three. Effects of inclination angle and elbows of the surge line on CCFL characteristics were also investigated experimentally. The effects of inclination angle on CCFL depend on the flow direction, that is, the effect is large for the nearly horizontal flow and small for the vertical flow at the upper junction. The presence of elbows increases the flow limitation in the surge line, whereas the flow limitations at the upper and lower junctions do not depend on the presence of elbows.

Prediction Method of Countercurrent Flow Limitation in a Pressurizer Surge Line and Its Evaluation for a 1/10-Scale Model

2016 ◽  
Vol 2 (3) ◽  
Author(s):  
Michio Murase ◽  
Yoichi Utanohara ◽  
Takayoshi Kusunoki ◽  
Dirk Lucas ◽  
Akio Tomiyama
Keyword(s):  
Numerical Simulations ◽  
Prediction Method ◽  
3D Simulation ◽  
Scale Model ◽  
Countercurrent Flow ◽  
Flow Limitation ◽  
Vertical Pipe ◽  
Pressurized Water ◽  
Surge Line ◽  
Inclined Pipe

The method for predicting countercurrent flow limitation (CCFL) and its uncertainty in an actual pressurizer surge line of a pressurized water reactor (PWR) using 1/10-scale air–water experimental data, one-dimensional (1D) computations, and three-dimensional (3D) numerical simulations was proposed. As one step of the prediction method, 3D numerical simulations were carried out for countercurrent air–water flows in a 1/10-scale model of the pressurizer surge line to evaluate capability of the 3D simulation method and decide uncertainty of CCFL characteristics evaluated for the 1/10-scale model. The model consisted of a vertical pipe, a vertical elbow, and a slightly inclined pipe with elbows. In the actual 1/10-scale experiment, air supplied into the lower tank flowed upward to the upper tank and water supplied into the upper tank gravitationally flowed downward to the lower tank through the pressurizer surge line. In the 3D simulation, however, water was supplied from the wall surface of the vertical pipe to avoid effects of flooding at the upper end (the 3D simulation largely underestimated falling water flow rates at the upper end). Then, the flow pattern in the slightly inclined pipe was successfully reproduced, and the simulated CCFL values for the inclination angle of θ=0.6  deg (slope of 1/100) agreed well with the experimental CCFL data. The uncertainty among air–water experiments, 1D computations, and 3D simulations for the 1/10-scale model was dC=±0.015 for the CCFL constant of C=0.50. The effects of θ (θ=0,1.0 deg) on CCFL characteristics were simulated and discussed.

scholarly journals Effects of Diameters on Countercurrent Flow Limitation at a Square Top End in Vertical Pipes

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Michio Murase ◽  
Koji Nishida ◽  
Toshihide Torige ◽  
Toshiya Takaki ◽  
Raito Goda ◽  
...  
Keyword(s):  
Water Level ◽  
Flow Rate ◽  
Liquid Flow ◽  
Liquid Flow Rate ◽  
Strong Relationship ◽  
Countercurrent Flow ◽  
Flow Limitation ◽  
Vertical Pipe ◽  
Surge Line ◽  
Inclined Pipe

The falling liquid flow rate under flooding conditions is limited at a square top end of a vertical pipe in the pressurizer surge line with the diameter of about 300 mm that consists of a vertical pipe, a vertical elbow, and a slightly inclined pipe with elbows. In this study, therefore, we evaluated effects of diameters on countercurrent flow limitation (CCFL) at the square top end in vertical pipes by using existing air-water data in the diameter range of D = 19-250 mm. As a result, we found that there was a strong relationship between the constant CK and the slope m in the Wallis-type correlation where the Kutateladze parameters were used for the dimensionless gas and liquid velocities. The constant CK and the slope m increased when the water level is increased in the upper tank h. CCFL at the square top end of the vertical pipes could be expressed by the Kutateladze parameters with CK = 1.53±0.11 and m = 0.97 for D ≥ 30 mm. The CK values were smaller for D = 19-25 mm than those for D ≥ 30 mm.

Countercurrent flow limitation at a square top end of vertical pipes and in a pressurizer surge line

2020 ◽  
Vol 363 ◽  
pp. 110624
Author(s):  
Toshiya Takaki ◽  
Michio Murase ◽  
Koji Nishida ◽  
Toshihide Torige ◽  
Akio Tomiyama
Keyword(s):  
Countercurrent Flow ◽  
Flow Limitation ◽  
Surge Line

Countercurrent flow limitation in a pressurizer surge line

2018 ◽  
Vol 326 ◽  
pp. 175-182 ◽  
Author(s):  
Yasunori Yamamoto ◽  
Michio Murase ◽  
Akio Tomiyama
Keyword(s):  
Countercurrent Flow ◽  
Flow Limitation ◽  
Surge Line

scholarly journals Countercurrent Flow Limitation at the Junction between the Surge Line and the Pressurizer of a PWR

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Taiga Doi ◽  
Takashi Futatsugi ◽  
Michio Murase ◽  
Kosuke Hayashi ◽  
Shigeo Hosokawa ◽  
...  
Keyword(s):  
Gas Flow ◽  
Low Frequency ◽  
Water Levels ◽  
Countercurrent Flow ◽  
Flow Limitation ◽  
Cylindrical Tank ◽  
Two Phase ◽  
Surge Line ◽  
Cylindrical Tanks ◽  
Tank Geometry

An experimental study on countercurrent flow limitation (CCFL) in vertical pipes is carried out. Effects of upper tank geometry and water levels in the upper and lower tanks on CCFL characteristics are investigated for air-water two-phase flows at room temperature and atmospheric pressure. The following conclusions are obtained: (1) CCFL characteristics for different pipe diameters are well correlated using the Kutateladze number if the tank geometry and the water levels are the same; (2) CCFL occurs at the junction between the pipe and the upper tank both for the rectangular and cylindrical tanks, and CCFL with the cylindrical tank occurs not only at the junction but also inside the pipe at high gas flow rates and small pipe diameters; (3) the flow rate of water entering into the vertical pipe at the junction to the rectangular upper tank is lower than that to the cylindrical tank because of the presence of low frequency first-mode sloshing in the rectangular tank; (4) increases in the water level in the upper tank and in the air volume in the lower tank increase water penetration into the pipe, and therefore, they mitigate the flow limitation.

Countercurrent Flow Limitation in Slightly Inclined Pipes With Elbows

2015 ◽  
Vol 1 (4) ◽  
Author(s):  
Michio Murase ◽  
Ikuo Kinoshita ◽  
Takayoshi Kusunoki ◽  
Dirk Lucas ◽  
Akio Tomiyama
Keyword(s):  
Friction Coefficient ◽  
Single Phase ◽  
Wall Friction ◽  
Scale Model ◽  
Gas Flows ◽  
Countercurrent Flow ◽  
Flow Limitation ◽  
Adjustment Factor ◽  
Pressurized Water ◽  
Inclined Pipes

One-dimensional (1D) sensitivity computations were carried out for air–water countercurrent flows in a 1/15-scale model of the hot leg and a 1/10-scale model of the pressurizer surge line in a pressurized water reactor (PWR) to generalize the prediction method for countercurrent flow limitation (CCFL) characteristics in slightly inclined pipes with elbows. In the 1D model, the wall friction coefficient fwG of single-phase gas flows was used. The interfacial drag coefficient of fi=0.03, an appropriate adjustment factor of NwL=6 for the wall friction coefficient fwL of single-phase liquid flows (NwG=1 for fwG of single-phase gas flows), and an appropriate adjustment factor of Nde=6 for the pressure loss coefficient ζe of elbows in single-phase flows were determined to give good agreement between the computed and measured CCFL characteristics. The adjusted factors were used to compute and then discuss effects of the inclination angle and diameter on CCFL characteristics.

scholarly journals Design and Calibration of a Hall Effect System for Measurement of Six-Degree-of-Freedom Motion within a Stacked Column

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3740
Author(s):  
Olafur Oddbjornsson ◽  
Panos Kloukinas ◽  
Tansu Gokce ◽  
Kate Bourne ◽  
Tony Horseman ◽  
...  
Keyword(s):  
Hall Effect ◽  
Degrees Of Freedom ◽  
Reactor Core ◽  
Degree Of Freedom ◽  
Life Extension ◽  
Scale Model ◽  
Design Development ◽  
Seismic Safety ◽  
Six Degrees Of Freedom ◽  
Six Degree Of Freedom

This paper presents the design, development and evaluation of a unique non-contact instrumentation system that can accurately measure the interface displacement between two rigid components in six degrees of freedom. The system was developed to allow measurement of the relative displacements between interfaces within a stacked column of brick-like components, with an accuracy of 0.05 mm and 0.1 degrees. The columns comprised up to 14 components, with each component being a scale model of a graphite brick within an Advanced Gas-cooled Reactor core. A set of 585 of these columns makes up the Multi Layer Array, which was designed to investigate the response of the reactor core to seismic inputs, with excitation levels up to 1 g from 0 to 100 Hz. The nature of the application required a compact and robust design capable of accurately recording fully coupled motion in all six degrees of freedom during dynamic testing. The novel design implemented 12 Hall effect sensors with a calibration procedure based on system identification techniques. The measurement uncertainty was ±0.050 mm for displacement and ±0.052 degrees for rotation, and the system can tolerate loss of data from two sensors with the uncertainly increasing to only 0.061 mm in translation and 0.088 degrees in rotation. The system has been deployed in a research programme that has enabled EDF to present seismic safety cases to the Office for Nuclear Regulation, resulting in life extension approvals for several reactors. The measurement system developed could be readily applied to other situations where the imposed level of stress at the interface causes negligible material strain, and accurate non-contact six-degree-of-freedom interface measurement is required.

scholarly journals Cat-CrNP as new material with catalytic properties for 2-chloro-2-propen-1-ol and ethylene oligomerizations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jacek Malinowski ◽  
Dagmara Jacewicz ◽  
Artur Sikorski ◽  
Mariusz Urbaniak ◽  
Przemysław Rybiński ◽  
...  
Keyword(s):  
Complex Compound ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Organometallic Compounds ◽  
Ethylene Oligomerization ◽  
High Catalytic Activity ◽  
New Material ◽  
Activity Requirement ◽  
Olefin Oligomerization ◽  
Xrd Method

AbstractThe contemporary search for new catalysts for olefin oligomerization and polymerization is based on the study of coordinating compounds and/or organometallic compounds as post-metallocene catalysts. However known catalysts are suffered by many flaws, among others unsatisfactory activity, requirement of high pressure or instability at high temperatures. In this paper, we present a new catalyst i.e. the crystalline complex compound possesing high catalytic activity in the oligomerization of olefins, such as 2-chloro-2-propen-1-ol and ethylene under very mild conditions (room temperature, 0.12 bar for ethylene oligomerization, atmospheric pressure for 2-chloro-2-propen-1-ol oligomerization). New material—Cat-CrNP ([nitrilotriacetato-1,10-phenanthroline]chromium(III) tetrahydrate) has been obtained as crystalline form of the nitrilotriacetate complex compound of chromium(III) with 1,10-phenanthroline and characterized in terms of its crystal structure by the XRD method and by multi-analytical investigations towards its physicochemical propeties The yield of catalytic oligomerization over Cat-CrNP reached to 213.92 g · mmol−1 · h−1· bar−1 and 3232 g · mmol−1 · h−1 · bar−1 for the 2-chloro-2-propen-1-ol and ethylene, respectively. Furthemore, the synthesis of Cat-CrNP is cheap, easy to perform and solvents used during preparation are environmentally friendly.

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