Double leaf insulating wall is widely applied in many fields, such as air-planes, high-speed trains cars and so on, because the performance of transmission loss is higher than that of single panel of the same weight. ...
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ISBN:
(纸本)9781627485609
Double leaf insulating wall is widely applied in many fields, such as air-planes, high-speed trains cars and so on, because the performance of transmission loss is higher than that of single panel of the same weight. But transmission loss of double leaf wall is apt to be decreased by resonance between the panels and air space of the wall. Local depression of transmission loss by resonance transmission is often observed. We tried to improve this problem of transmission loss by using dynamic vibration absorber. Our purpose was to investigate the effectiveness of the small and light-weight dynamic vibration absorbers and suitable positions to set them, and to investigate the usefulness of computational analysis for this problem through experiments. We found that even dynamic vibration absorbers were small and light-weight, they were effective, if they had suitable vibration damping and they were equipped at suitable positions. We found that the most suitable position to be equipped and the amount of improvement for transmission loss were computed fairly well by comparing between experimental and computed results. And it was observed and confirmed that the dynamic vibration absorber worked to excite the vibration modes to arise acoustic cancellation effectively through using lazer Doppler scanning apparatus and computed visualizations of surface vibration modes of the panel.
In this paper, the exemplary results of the IEA Wind Task 30 "Offshore Code Comparison Collaboration Continuation" (OC4) Project - Phase I, focused on the coupled simulation of an offshore wind turbine (OWT)...
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During an overpower transient, the fuel rod cladding may be subjected to major stresses due to differential expansion of the fuel and the cladding. This may lead to clad failure through the Pellet Clad Interaction (PC...
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During an overpower transient, the fuel rod cladding may be subjected to major stresses due to differential expansion of the fuel and the cladding. This may lead to clad failure through the Pellet Clad Interaction (PCI) phenomenon. So the aim of this paper is to present the linear power reached during the most limiting condition II transients(Excessive Load Increase (ELI), Uncontrolled RCCA Withdrawal at Power (URWP) and undetected Rod Drop (RD)) with respect to Qinshan-II long cycle fuel management project PCI analysis.
Hydrogen combustion in the containment building may be a threat to containment *** in some subcompartments,hydrogen detonation is more easier to happen,which may destroy the containment structure or the safety equipme...
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Hydrogen combustion in the containment building may be a threat to containment *** in some subcompartments,hydrogen detonation is more easier to happen,which may destroy the containment structure or the safety equipments in the containment. A study has been carried out using the GASFLOW three-dimensional CFD code to evaluate the hydrogen distribution in the subcompartment during a severe *** Chinese 600MW NPP containment is modeling by GASFLOW. The GASFLOW calculation gave detailed results for the spatial distribution of gas concentrations in the reactor coolant pump(RCP) compartment and the steam generator(SG) compartment within containment.
The advanced pressurized water reactor with a tight hexagonal lattice has its potential to improve uranium utilization. With a smaller pitch-to-diameter ratio(p/d) ranging from 1.06 to 1.20, a major problem is the eme...
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The advanced pressurized water reactor with a tight hexagonal lattice has its potential to improve uranium utilization. With a smaller pitch-to-diameter ratio(p/d) ranging from 1.06 to 1.20, a major problem is the emergency core cooling in a loss-of-coolant accident. The NEPTUN-III and FLORESTAN flooding experiments at PSI and KfK have been performed during the verification period 1985-1990, and the results shows that the reflooding behavior of LWHCR is quite different from that of LWR with higher peak clad temperatures and smaller quench rates. The existing system codes like RELAP5, CATHARE, TRAC may not be able to be used in the calculations of the reflooding phase of LWHCR. Though some efforts have been put into the validation of the improvement of codes, the results are not so good. In this study, the characteristics of the reflooding behavior of tight lattice are pointed out, and the deficiencies of the reflooding models of RELAP5/MOD3 are also fount out after a simulation of the NEPTUN-III reflooding test. The precursory cooling in tight lattice is not effective especially at low reflooding rates (<4cm/s), the droplet enhancement is not significant compared to LWR, and the vapor Reynolds number is much smaller. Finally, a few modifications to RELAP5/MOD3 are made. Compared with the original code, the modified one can better predict the reflooding phase of tight lattice especially the peak clad temperatures at low reflooding rates. More work should be done to deal with the heat transfer characteristics in the transition region of reflooding in tight lattice..
plate fuel assembly is widely used as the research reactor core geometry due to the narrow rectangular channel benefit, but the research on the post-CHF thermal-hydraulic characteristics in the narrow rectangular chan...
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plate fuel assembly is widely used as the research reactor core geometry due to the narrow rectangular channel benefit, but the research on the post-CHF thermal-hydraulic characteristics in the narrow rectangular channel is few. Once the loss of coolant accident (LOCA) happens the post-CHF thermal-hydraulic characteristics is important for the accident mitigation. This paper studies the characteristics of the inverted annular flow regime during the narrow channel through the comparison between narrow and general channel inside tube heat reflooding experiment, give the assumptions of the post-CHF reflooding flow regime. Then through the comparison of narrow annular channel experimental wall temperature with the RELAP5 simulation wall temperature for this experiment process. The far downstream of the quench front heat flux is obviously lower than the calculated value, so the wall temperature is higher than the calculated wall temperature. The quality is assumed lower during the far downstream of the quench front in the narrow channel experiment. Because the liquid is consumed during the close downstream of the quench front. Through the comparison of the wall temperature between the calculated by code and experimental value, the liquid core in the inverted annular flow regime which may appears during close downstream of the quench front shortly will breakup earlier due to the more severe surrounding steam disturbing, bringing on the quickly consumption of the liquid, then the quality during far downstream of the quench front is higher than general channel.
Direct numerical simulation is a powerful research tool, which provides a level of information and accuracy that cannot be equaled with other approaches. In this paper, the development of a CFD code for direct numeric...
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Direct numerical simulation is a powerful research tool, which provides a level of information and accuracy that cannot be equaled with other approaches. In this paper, the development of a CFD code for direct numerical simulation is described, which is named dnsPisoFoam. In order to validate the code, direct numerical simulation of channel flow with dnsPisoFoam was performed. The present results are compared with existing simulation results and shows good agreement.
Introduce the basic concept of best rational approximation and constructing procedure of the best rational approximation function in Laplace domain. By an illustrative example the design method of FOC based on best ra...
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Introduce the basic concept of best rational approximation and constructing procedure of the best rational approximation function in Laplace domain. By an illustrative example the design method of FOC based on best rational approximation is discussed. The performance comparison of transfer functions between the FOC obtained by best rational approximation method and conventional PID shows that it is effective to apply the method in design of FOC, which can guarantee maximum absolute error of amplitude frequency characteristic of approximation function in a given error tolerance.
This paper describes a calculation model for pre-stressed bolted joints used to connect turntable bearing to the flanges. A traditional pre-stressed bolted joint calculation model is described and its insufficiencies ...
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Based on BPR theory, the new product development and manufacturing process status of a discrete manufacturing enterprise was analysed with finding out its existing problems, then a new reasonable process was designed ...
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