scholarly journals Experimental Investigation on Flow-Induced Vibration of Fuel Rods in Supercritical Water Loop

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Licun Wu ◽  
Daogang Lu ◽  
Yu Liu
Keyword(s):  
Fuel Assembly ◽  
Flow Rate ◽  
Supercritical Water ◽  
Vibrational Energy ◽  
Experimental Result ◽  
Small Scale ◽  
Leakage Flow ◽  
Flow Induced Vibration ◽  
Fuel Rods ◽  
Vibration Experiment

The supercritical water-cooled reactor (SCWR) is one of the most promising Generation IV reactors. In order to make the fuel qualification test for SCWR, a research plan is proposed to test a small scale fuel assembly in a supercritical water loop. To ensure the structure safety of fuel assembly in the loop, a flow-induced vibration experiment was carried out to investigate the vibration behavior of fuel rods, especially the vibration caused by leakage flow. From the experiment result, it can be found that: the vibration of rods is mainly caused by turbulence when flow rate is low. However, the effects of leakage flow become obvious as flow rate increases, which could changes the distribution of vibrational energy in spectrum, increasing the vibrational energy in high-frequency band. That is detrimental to the structure safety of fuel rods. Therefore, it is more reasonable to improve the design by using the spacers with blind hole, which can eliminate the leakage flow, to assemble the fuel rods in supercritical water loop. On the other hand, the experimental result could provide a benchmark for the theoretical studies to validate the applicability of boundary condition set for the leakage-flow-induced vibration.

Crucial Factors Analysis of 5×5 Grid Flow-Induced Vibration Test

2017 ◽  
Author(s):  
C. Z. Zhang ◽  
J. Ding ◽  
Y. X. Zheng ◽  
F. J. Gan ◽  
S. J. Gong ◽  
...  
Keyword(s):  
Fuel Assembly ◽  
Flow Rate ◽  
High Frequency ◽  
Vibration Velocity ◽  
Small Scale ◽  
Laser Vibrometer ◽  
Flowing Water ◽  
Flow Induced Vibration ◽  
High Frequency Vibration ◽  
Test Assembly

5×5 small-scale test fuel assembly was manufactured to carry out flow-induced vibration tests, aiming to obtain the vibration responses of new designed grid subjected to axial-flowing water. This test was carried out in a hydraulic loop with the maximum flow rate of 65 m3/h and room temperature and pressure. Laser vibrometer was used to measure the vibrating velocity of grid straps. The vibration peaks were generally distributed in three domains of the frequency spectrum. The first domain is from zero to decades of Hz, in which the vibration may be turbulence-buffeting-induced test assembly vibration as an integer entity. The second domain is from decades to hundreds of Hz, in which the vibration may also be test assembly vibration as an integer entity due to turbopump-induced pressure wave. The third domain is above 1000Hz, in which the vibration may be local strap vibration mainly due to vortex shedding along the edges of the straps. Series of tests were accomplished to figure out the characteristics of the trend of maximum high-frequency vibration velocity and related frequency with increasing flow rate. The high-frequency vibration characteristics of the grid in axial-flowing water are crucial for the fuel assembly designers when evaluating the anti-abrasion performance of fuel rods under reactor flow rate conditions.

Influences of wear-ring clearance leakage on performance of a small-scale pump-turbine

2019 ◽  
Vol 234 (4) ◽  
pp. 454-469 ◽  
Author(s):  
Jianru Yan ◽  
Zhitao Zuo ◽  
Wenbin Guo ◽  
Hucan Hou ◽  
Xin Zhou ◽  
...  
Keyword(s):  
Flow Rate ◽  
Total Pressure ◽  
Labyrinth Seal ◽  
Work Capacity ◽  
Small Scale ◽  
Leakage Flow ◽  
Pump Mode ◽  
Pump Turbine ◽  
Flow Angle ◽  
Turbine Mode

Wear-ring clearance leakage would affect performance of pump-turbine significantly. In this paper, the variation of the leakage and efficiency of flat ring seal and labyrinth seal are numerically studied on one pump-turbine when the width of clearance is 0.2 mm and 0.5 mm. The result shows that the effect of leakage flow cannot be neglected. The pump-turbine performance affected by leakage in turbine mode is more than that in pump mode at the same sealing structure and width of clearance. Each component’s proportion of total pressure loss hardly varies with flow rate at pump mode, which is opposite to that at turbine mode. Leakage does not change proportionally with system flow rate. When the width of clearance decreases to 0.2 mm, the leakage is reduced obviously because the maximum entropy occurs in the front pump chamber. The mixing of leakage flow and mainstream at impeller inlet at pump mode will increase the total pressure and decrease the flow angle and relative flow angle. Finally, it reduces the impeller’s work capacity.

Flow-Induced Grid-to-Rod Fretting Test and Simulation for NFI PWR Fuel Assembly

2013 ◽  
Author(s):  
Shota Okui ◽  
Yuichiro Kubo ◽  
Shumpei Kakinoki ◽  
Roger Y. Lu ◽  
Zeses Karoutas ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Fuel Assembly ◽  
Wear Test ◽  
Flow Induced Vibration ◽  
Fuel Rods ◽  
Spacer Grids ◽  
Fuel Rod ◽  
Non Linear ◽  
Computational Fluid Dynamics Cfd

A long-term flow-induced vibration and wear test was performed for a full-scale 17×17 PWR fuel mockup, and the test results were compared with numerical simulations. The flow-induced vibration on a fuel assembly or fuel rods may cause Grid-to-Rod Fretting (GTRF) and result in the leakage of fuel rods in PWRs. GTRF involves non-linear vibration of a fuel rod due to the excitation force induced by coolant flow around a fuel rod. So, the numerical simulation is performed by VITRAN (Vibration Transient Analysis Non-linear) and Computational Fluid Dynamics (CFD). VITRAN code was developed by Westinghouse to simulate fuel rod flow induced vibration and GTRF. In this paper, it was confirmed that the code can reproduce GTRF wear for NFI fuel assembly. CFD calculation is performed to obtain the axial and lateral flow velocity around the fuel rods, reflecting detailed geometries of fuel assembly components like bottom nozzle, spacer grids. The numerical simulation reasonably reproduced the vibration and wear test for NFI fuel assembly.

Flow-Induced Vibration Analysis of an Integral Economizer Once-Through Steam Generator

1989 ◽  
Vol 111 (4) ◽  
pp. 501-506
Author(s):  
M. K. Au-Yang ◽  
B. Brenneman
Keyword(s):  
Fuel Assembly ◽  
Steam Generator ◽  
Flow Rate ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
First Generation ◽  
Second Generation ◽  
Flow Induced Vibration ◽  
Operational Test

The integral economizer once-through steam generator is a second-generation steam generator used in B&W’s 205-fuel assembly nuclear power plants. Besides having an integral economizer, this steam generator differs from the first generation units, sixteen of which have been operating with B&W’s 177 fuel assembly nuclear power plants for more than ten years, in having a much higher flow rate. This higher flow rate induces a correspondingly higher fluid-dynamic load on all of the steam generator internal components, particularly the tube bundle. This paper describes the flow-induced vibration design analysis of this second-generation nuclear steam generator. The three most commonly known flow-induced vibration phenomena were considered: fluid-elastic instability, turbulence-induced vibration and vortex-induced vibration. To minimize uncertainties in the many experimentally determined input parameters such as damping ratios, Connors’ constant and the dynamic pressure power spectral densities, a parallel analysis was carried out on the operating first-generation steam generator, and the results compared. The analytical results were verified by the recent start-up of B&W’s first 205-fuel assembly nuclear plant. No vibration problems were encountered during either the pre-operational test or in several months of full power operations.

European Project “Supercritical Water Reactor–Fuel Qualification Test”: Overview, Results, Lessons Learned, and Future Outlook

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Mariana Ruzickova ◽  
Ales Vojacek ◽  
Thomas Schulenberg ◽  
Dirk C. Visser ◽  
Radek Novotny ◽  
...  
Keyword(s):  
Fuel Assembly ◽  
Supercritical Water ◽  
Lessons Learned ◽  
Reactor Fuel ◽  
Small Scale ◽  
Plant Design ◽  
Qualification Test ◽  
Water Reactor ◽  
European Collaboration ◽  
Supercritical Water Reactor

The supercritical water reactor (SCWR) is one of the six reactor concepts being investigated under the framework of the Generation IV International Forum (GIF). One of the major challenges in the development of a SCWR is to develop materials for the fuel and core structures that will be sufficiently corrosion resistant to withstand supercritical water conditions and to gain thermal-hydraulic experimental data that could be used for further improvement of heat transfer predictions in the supercritical region by numerical codes. Previously, core, reactor, and plant design concepts of the European high-performance light water reactor (HPLWR) have been worked out in great detail. As the next step, it has been proposed to carry out a fuel qualification test (FQT) of a small-scale fuel assembly in a research reactor under typical prototype conditions. Design and licensing of an experimental facility for the FQT, including the small-scale fuel assembly, the required coolant loop with supercritical water, and safety and auxiliary systems, was the scope of the recently concluded project “Supercritical Water Reactor–Fuel Qualification Test” (SCWR-FQT) described here. This project was a collaborative project cofunded by the European Commission, which took advantage of a Chinese–European collaboration, in which China offered an electrically heated out-of-pile loop for testing of fuel bundles. The design of the facility, especially of the test section with the fuel assembly, and the most important results of steady-state and safety analyses are presented. Material test results of the stainless steels considered for the fuel cladding are briefly summarized. Finally, important outcomes and lessons learned in the “Education and Training” and “Management” work packages are presented.

Design of a Small-Scale Supercritical Water Oxidation Reactor. Part II: Numerical Modeling

2021 ◽  
Author(s):  
Anmol L. Purohit ◽  
John A. Misquith ◽  
Brian R. Pinkard ◽  
Stuart J. Moore ◽  
John C. Kramlich ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Small Scale ◽  
Supercritical Water Oxidation ◽  
Oxidation Reactor

scholarly journals Impact of Orifice-to-Pipe Diameter Ratio on Leakage Flow: An Experimental Study

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2189
Author(s):  
Tingchao Yu ◽  
Xiangqiu Zhang ◽  
Iran E. Lima Neto ◽  
Tuqiao Zhang ◽  
Yu Shao ◽  
...  
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Pipe Wall ◽  
Pressure Head ◽  
Diameter Ratio ◽  
Pipe Diameter ◽  
Leakage Flow ◽  
Leakage Flow Rate ◽  
Different Shapes ◽  
Real Scale

The traditional orifice discharge formula used to estimate the flow rate through a leak opening at a pipe wall often produces inaccurate results. This paper reports an original experimental study in which the influence of orifice-to-pipe diameter ratio on leakage flow rate was investigated for several internal/external flow conditions and orifice holes with different shapes. The results revealed that orifice-to-pipe diameter ratio (or pipe wall curvature) indeed influenced the leakage flow, with the discharge coefficient ( C d ) presenting a wide variation (0.60–0.85). As the orifice-to-pipe diameter ratio decreased, the values of C d systematically decreased from about 12% to 3%. Overall, the values of C d also decreased with β (ratio of pressure head differential at the orifice to wall thickness), as observed in previous studies. On the other hand, orifice shape, main pipe flow velocity, and external medium (water or air) all had a secondary effect on C d . The results obtained in the present study not only demonstrated that orifice-to-pipe diameter ratio affects the outflow, but also that real scale pipes may exhibit a relevant deviation of C d from the classical range (0.61–0.67) reported in the literature.

Effect of Active Modulation of Through-Casing Coolant Injection on Turbine Efficiency

2017 ◽  
Author(s):  
Brian M. T. Tang ◽  
Marko Bacic ◽  
Peter T. Ireland
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Total Pressure ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Turbine Efficiency ◽  
Coolant Injection ◽  
Cooling Air

This paper presents a computational investigation into the impact of cooling air injected through the stationary over-tip turbine casing on overall turbine efficiency. The high work axial flow turbine is representative of the high pressure turbine of a civil aviation turbofan engine. The effect of active modulation of the cooling air is assessed, as well as that of the injection locations. The influence of the through-casing coolant injection on the turbine blade over-tip leakage flow and the associated secondary flow features are examined. Transient (unsteady) sliding mesh simulations of a one turbine stage rotor-stator domain are performed using periodic boundary conditions. Cooling air configurations with a constant total pressure air supply, constant mass flow rate and actively controlled total pressure supply are assessed for a single geometric arrangement of cooling holes. The effects of both the mass flow rate of cooling air and the location of its injection relative to the turbine rotor blade are examined. The results show that all of the assessed cooling configurations provided a benefit to turbine row efficiency of between 0.2 and 0.4 percentage points. The passive and constant mass flow rate configurations reduced the over-tip leakage flow, but did so in an inefficient manner, with decreasing efficiency observed with increasing injection mass flow rate beyond 0.6% of the mainstream flow, despite the over-tip leakage mass flow rate continuing to reduce. By contrast, the active total pressure controlled injection provided a more efficient manner of controlling this leakage flow, as it permitted a redistribution of cooling air, allowing it to be applied in the regions close to the suction side of the blade tip which more directly reduced over-tip leakage flow rates and hence improved efficiency. Cooling air injected close to the pressure side of the rotor blade was less effective at controlling the leakage flow, and was associated with increased aerodynamic loss in the passage vortex.

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