The Experts below are selected from a list of 6072 Experts worldwide ranked by ideXlab platform
M. Ishii - One of the best experts on this subject based on the ideXlab platform.
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Design and test of hydraulic vacuum breaker Check Valve for simplified boiling water reactor
Nuclear Engineering and Design, 2006Co-Authors: H-j Yoon, Shripad T Revankar, Y. Xu, M. IshiiAbstract:In the current design of the simplified boiling water reactor, the vacuum breaker Check Valve is an important safety component. The vacuum breaker Check Valve is the only key safety components which is not passive in nature. Failure of this mechanical Valve drastically reduces the passive containment cooling system cooling capability and hence containment pressure may exceed the design pressure. To eliminate this problem novel vacuum breaker Check Valve was developed to replace the mechanical Valve. This new design is based on a passive hydraulic head, which is fail-safe and is truly passive in operation. Moreover this new design needs only one additional tank and one set of piping each to the wetwell and drywell. This system is simple in design and hence is easy to maintain and to qualify for operation. The passive vacuum breaker Check Valve performance was first evaluated using RELAP5. Then the passive vacuum breaker Check Valve was constructed and implemented in the PUMA integral test facility. Its performance was studied in a large break loss of coolant accident simulation test performed in PUMA facility. ?? 2006 Elsevier B.V. All rights reserved.
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Design and testing of vacuum breaker Check Valve for simplified boiling water reactor
International Conference on Nuclear Engineering Proceedings ICONE, 2002Co-Authors: M. Ishii, Y. Xu, Shripad T RevankarAbstract:A new design of the vacuum breaker Check Valve was developed to replace the mechanical Valve in a simplified boiling water reactor. Scaling and design calculations were performed to obtain the geometry of new passive hydraulic vacuum breaker Check Valve. In order to Check the Valve performance, a RELAP5 model of the simplified boiling water reactor system with the new Valve was developed. The Valve was implemented in an integral facility, PUMA and was tested for large break loss of coolant accident.
Shripad T Revankar - One of the best experts on this subject based on the ideXlab platform.
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Design and test of hydraulic vacuum breaker Check Valve for simplified boiling water reactor
Nuclear Engineering and Design, 2006Co-Authors: H-j Yoon, Shripad T Revankar, Y. Xu, M. IshiiAbstract:In the current design of the simplified boiling water reactor, the vacuum breaker Check Valve is an important safety component. The vacuum breaker Check Valve is the only key safety components which is not passive in nature. Failure of this mechanical Valve drastically reduces the passive containment cooling system cooling capability and hence containment pressure may exceed the design pressure. To eliminate this problem novel vacuum breaker Check Valve was developed to replace the mechanical Valve. This new design is based on a passive hydraulic head, which is fail-safe and is truly passive in operation. Moreover this new design needs only one additional tank and one set of piping each to the wetwell and drywell. This system is simple in design and hence is easy to maintain and to qualify for operation. The passive vacuum breaker Check Valve performance was first evaluated using RELAP5. Then the passive vacuum breaker Check Valve was constructed and implemented in the PUMA integral test facility. Its performance was studied in a large break loss of coolant accident simulation test performed in PUMA facility. ?? 2006 Elsevier B.V. All rights reserved.
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Design and testing of vacuum breaker Check Valve for simplified boiling water reactor
International Conference on Nuclear Engineering Proceedings ICONE, 2002Co-Authors: M. Ishii, Y. Xu, Shripad T RevankarAbstract:A new design of the vacuum breaker Check Valve was developed to replace the mechanical Valve in a simplified boiling water reactor. Scaling and design calculations were performed to obtain the geometry of new passive hydraulic vacuum breaker Check Valve. In order to Check the Valve performance, a RELAP5 model of the simplified boiling water reactor system with the new Valve was developed. The Valve was implemented in an integral facility, PUMA and was tested for large break loss of coolant accident.
Shengwei Wang - One of the best experts on this subject based on the ideXlab platform.
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enhancing the performance of large primary secondary chilled water systems by using bypass Check Valve
Energy, 2011Co-Authors: Shengwei WangAbstract:Large primary-secondary chilled water systems often suffer from low chilled water temperature difference (i.e., known as low delta-T central plant syndrome) during operation. This paper presents a detailed study to investigate the feasibility and potential benefits related to the use of a bypass Check Valve in the chiller decouple line to solve this operational problem and hence, to improve the overall system operating efficiency. The objective of this study is to provide some guidance and necessary confidence as well as the awareness of potential problems that may arise when a bypass Check Valve is considered to handle the low delta-T syndrome. Based on testing the effects of the low delta-T syndrome, the performances of the systems with and without the bypass Check Valve are then evaluated by using a simulated virtual system. In the tests, the low delta-T syndrome was introduced through air-side fouling by changing the air-side thermal resistance coefficient in the cooling coil model. The results show that, if the chilled water system suffered from 20% air-side fouling, about 6.77% total energy of the chilled water system studied can be saved when a bypass Check Valve is used, as compared to that without the bypass Check Valve.
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performance enhancement of a complex chilled water system using a Check Valve experimental validation
Applied Thermal Engineering, 2010Co-Authors: Shengwei WangAbstract:Abstract The large primary–secondary chilled water systems often suffer from the excess flow demand and low chilled water temperature difference, which is known as the low ΔT central plant syndrome, during operation. This paper presents an approach for experimental validation of the possible utility of a Check Valve (i.e., putting a one-direction Check Valve in the chilled water by-pass line) to solve this operational problem and enhance the overall system performance, prior to a Check Valve is really installed. The experimental tests were carried out on the complex central chiller plant in a super high-rise building using a simulated Check Valve through fully closing one of the butterfly Valves in the by-pass line when the system operated with a significant excess flow demand and experienced the low ΔT syndrome. The results from the tests showed that the system operational performance can be improved when the simulated Check Valve was used. Compared to that without using the Check Valve, about 9.2% of the total energy of the chillers and secondary water pumps was saved in the test period when the simulated Check Valve was used.
Zeng Xiangwei - One of the best experts on this subject based on the ideXlab platform.
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Numerical Simulation of Closing Process of Shuttle Check Valve
The Open Mechanical Engineering Journal, 2015Co-Authors: Xiang Kefeng, Zeng XiangweiAbstract:For studying the kinetic characteristics of passive shuttle Check Valve at the moment that it closes its Valve core on the condition of high pressure differences, this paper first constructs the equation of motion of the Valve core and two- dimensional geometrical model by using computation fluid dynamics method, then with the help of the calculation method and physical model provided by Fluent software, employing the dynamic mesh and user-defined functions, simulates the unsteady flow in the Valve core's closing process under the different pressure fluctuations, and obtains the stress nephogram, the velocity vector diagram, the speed curve, and pressure curve of the interior flow field of the Valve. The results show that the bigger the value of Valve fluctuation is, the larger the fluid pressure that the Valve core is subjected to, the openness of the core and the speed fluctuation of the core are, and that in the case of sudden decompression at the entrance, the core can be shut down quickly with the steady speed field and pressure field. The simulation results are conducive to the design and optimization of structure parameter of shuttle Check Valve. The shuttle Check Valve invented by Zeng Xiangwei can automatically open and close itself under the control of the energy of the pipeline system, needing no extra power or control. The shuttle Check Valve can be closed safely and quickly in a relatively small back pressure due to its reasonable structure (1), and it now has been used in tens of large chemical plants and oil plants in China. In recent years, many researchers have been studying the shuttle Check Valve (2-6). Li Liangchao (7) finished the numerical simulation of the opening process of shuttle Valves; Chen Kun (8) analyzed the characteristic of the water attack in the shuttle Valve pipe system; RenYuxin (9) simulated the noise-reduction feature of the shuttle Valve. Yet few studies on the Valve score's activity during the closing process of shuttle Valve under the fluctuant pressure have come out. Simulation of the Valve has been developed from the steady simulation at a certain opening degree to the non-steady simulation under a certain motion law. Therefore, it is necessary to study the impact of the pressure differences between the inlet and the outlet upon the closing process of the Valve. The paper simulates the motion of the Valve clack during the Valve closing; provides the reference to the design of the structure parameter of the shuttle Check Valve and optimization. 2. STRUCTURE OF SHUTTLE Check Valve The structure of shuttle Check Valve is shown in Fig. (1). The outside is the Valve body and the inside is the spool, and a spring is placed in the rear of Valve spool for pre- tightening. When medium flows into the left side of the picture, and the fluid's pressure on the spool is larger than the pressure of the spring and fluid from the right on the spool, the Valve will move towards the right, and consequently Valve is opened and the fluid will flow from the left to the right. When the pressure of the fluid from the left is less than the pressure of the fluid from the right and the spring's acting force, the spool will move to the left and consequently the Valve is closed and backflow is prevented. Because the closing results from the spring's force and the pressure differences of both sides, therefore, the shuttle Check Valve can act as non-return function even in the case of the lowest backpressure (10). Functionally speaking, the shuttle Check Valve can function as opening and closing, throttling, damping, and amplify regulator and controller.
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research on the noise reduction performance of passive shuttle type anti water attack Check Valve
Machine Tool & Hydraulics, 2011Co-Authors: Zeng XiangweiAbstract:The operating principle of the viscous fluid damper in passive shuttle-type anti-water-attack Check Valve was analyzed.The flow field of the Check Valve was simulated with ADINA software.The results show that the variation of velocity and the pressure distribution within the Valve is axially symmetric and the function of noise reduction as well as the shock absorption is obvious.After modeling for the Valve and simulating with MATLAB software,the results show that the opening and closing time can be adjusted by the viscous fluid damper,and the pressure of water hammer is made to reduce to the minimum,which is basically anastomosis with the experiment.Therefore,the water attack damage to pressure pipeline can be weaken effectively by the viscous fluid damper and it is significant for the protection of pressure pipeline.
Y. Xu - One of the best experts on this subject based on the ideXlab platform.
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Design and test of hydraulic vacuum breaker Check Valve for simplified boiling water reactor
Nuclear Engineering and Design, 2006Co-Authors: H-j Yoon, Shripad T Revankar, Y. Xu, M. IshiiAbstract:In the current design of the simplified boiling water reactor, the vacuum breaker Check Valve is an important safety component. The vacuum breaker Check Valve is the only key safety components which is not passive in nature. Failure of this mechanical Valve drastically reduces the passive containment cooling system cooling capability and hence containment pressure may exceed the design pressure. To eliminate this problem novel vacuum breaker Check Valve was developed to replace the mechanical Valve. This new design is based on a passive hydraulic head, which is fail-safe and is truly passive in operation. Moreover this new design needs only one additional tank and one set of piping each to the wetwell and drywell. This system is simple in design and hence is easy to maintain and to qualify for operation. The passive vacuum breaker Check Valve performance was first evaluated using RELAP5. Then the passive vacuum breaker Check Valve was constructed and implemented in the PUMA integral test facility. Its performance was studied in a large break loss of coolant accident simulation test performed in PUMA facility. ?? 2006 Elsevier B.V. All rights reserved.
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Design and testing of vacuum breaker Check Valve for simplified boiling water reactor
International Conference on Nuclear Engineering Proceedings ICONE, 2002Co-Authors: M. Ishii, Y. Xu, Shripad T RevankarAbstract:A new design of the vacuum breaker Check Valve was developed to replace the mechanical Valve in a simplified boiling water reactor. Scaling and design calculations were performed to obtain the geometry of new passive hydraulic vacuum breaker Check Valve. In order to Check the Valve performance, a RELAP5 model of the simplified boiling water reactor system with the new Valve was developed. The Valve was implemented in an integral facility, PUMA and was tested for large break loss of coolant accident.