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Bottom Structure

The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

Xiao Xi – 1st expert on this subject based on the ideXlab platform

  • Analysis about the Slamming Pressure Peak Value on a Flat-Bottom Structure
    Journal of Shanghai Jiaotong University, 2006
    Co-Authors: Xiao Xi

    Abstract:

    The water entry of a flat-Bottom Structure was studied by using simulation software MSC.Dytran.A 2D finite element model was built up and some cases including the flat-Bottom Structure with different constant velocities and initial velocities impacting the water were calculated.The results show that the air captured by the flat-Bottom Structure acts as a buffer cushion and reduces the slamming pressure greatly.The mass of the Structure also has a great effect on the slamming pressure.The effect of air cushion and the mass of Structure was analyzed and a formula was given to calculate the peak value of slamming pressure.The study shows that the simulation method is an effective way for the water entry problems.

  • The Distribution of Slamming Pressure on Flat-Bottom Structure
    , 2005
    Co-Authors: Xiao Xi

    Abstract:

    While an object enters into the water with a certain velocity,it will get pressure from the water.Usually the pressure will persist in a short time but the quantity of it is rather great.Some researches about the water entry of flat-Bottom Structure are performed by means of simulation software in this paper.2-D finite element model is established and many cases including the flat-Bottom Structure with different constant velocity entering into the water are calculated.After analyzing the results of simulation,it is found that at the moment of Structure arriving the water surface the pressure acting on the slamming surface increases quickly and comes to peak value at the position of the primary water surface.The persisting time of the slamming pressure shortens as the increasing of the slamming velocity of the Structure.The pressure on the slamming surface is also not even.Center position of the slamming surface gets the biggest pressure while the edge gets small.Authors analyze the persisting time and distribution of the slamming pressure and regress a formula of the pressure distribution on the slamming surface.

  • Simulation Analysis on the Role of Air Cushion in the Slamming of a Flat-Bottom Structure
    Journal of Shanghai Jiaotong University, 2005
    Co-Authors: Xiao Xi

    Abstract:

    Study on the water entry of a flat-Bottom Structure was carried out by means of a simulation method. Two dimensional finite element models were established and the factor of air cushion and gravity was considered. In the calculation the mixture status of air layer and water was observed and the variation of physical parameters such as density, specific internal energy (SIE) and pressure were recorded. And (also) the effect of free water surface and splash was analyzed and the production mechanism of the peak value of impact pressure was discussed.

Yoshiyuki Inagaki – 2nd expert on this subject based on the ideXlab platform

  • R&D on thermal hydraulics of core and core–Bottom Structure
    Nuclear Engineering and Design, 2004
    Co-Authors: Yoshiyuki Inagaki, Ryutaro Hino, Kazuhiko Kunitomi, Kazuyuki Takase, Ikuo Ioka, So Maruyama

    Abstract:

    Abstract Thermal hydraulic tests on the core and core–Bottom Structure of the high-temperature engineering test reactor (HTTR) were carried out with the helium engineering demonstration loop (HENDEL) under simulated reactor operating conditions. The HENDEL was composed of helium gas circulation loops, mother sections (M 1 and M 2 ) and adaptor section (A), and two test sections, i.e. the fuel stack test section ( T 1 ) and in-core Structure test section ( T 2 ). In the T 1 test section simulating a fuel stack of the core, thermal and hydraulic performances of helium gas flowing through a fuel block were investigated for thermal design of the HTTR core. In the T 2 test section simulating the core–Bottom Structure, demonstration tests were performed to verify the structural integrity of graphite and metal components, seal performance against helium gas leakage among the graphite permanent blocks and thermal mixing performance of helium gas. The above test results in the T 1 and T 2 test sections were applied to the detailed design and licensing works of the HTTR and the HENDEL-loop was dismantled in 1999.

  • Seismic Response of the High-Temperature Engineering Test Reactor Core Bottom Structure
    Nuclear Technology, 1992
    Co-Authors: Tatsuo Iyoku, Masatoshi Futakawa, Yoshiyuki Inagaki, Shusaku Shiozawa, Toshiyo Miki

    Abstract:

    This paper discusses the High-Temperature Engineering Test Reactor (HTTR) a 30-MW (thermal) helium gas-cooled rector that uses a prismatic block. The core Bottom Structure (CBS) of the HTTR consists of an arrangement of graphite components, and it supports the core elements within the reactor vessel. vibration tests are performed with two scale models to clarify the seismic response of the CBS. The vibration characteristics of the CBS are clarified quantitatively, and the structural integrity of the graphite components is confirmed.

  • Thermal-Hydraulic Characteristics of Coolant in the Core Bottom Structure of the High-Temperature Engineering Test Reactor
    Nuclear Technology, 1992
    Co-Authors: Yoshiyuki Inagaki, Kazuhiko Kunitomi, Ikuo Ioka, Yoshiaki Miyamoto, Kunihiko Suzuki

    Abstract:

    This paper discusses the high-temperature engineering test reactor (HTTR), a 30-MW (thermal) helium gas-cooled reactor being constructed by the Japan Atomic Energy Research Establishment. A thermal mixing study of the coolant in the core Bottom Structure (CBS) of the HTTR is conducted to clarify the thermal-hydraulic characteristics of the coolant and estimate the influence of a hot streak on the intermediate heat exchanger (IHX) and a pressurized water cooler (PWC) down-stream from the core. An experiment is carried out using an in-core Structure test section (a full-scale simulation model of the (CBS) of the helium engineering demonstration loop (HENDEL), and a numerical analysis is made using a three-dimensional time-dependent flow and heat transfer code including a k-{epsilon} model of turbulence. It is confirmed that the coolant is mixed sufficiently in the CBS and the outlet gas duct of the HTTR, and the hot streak had little effect on the IHX and the PWC.

Chen Zhen – 3rd expert on this subject based on the ideXlab platform

  • Simulation of Flat-Bottom Structure Slamming
    , 2005
    Co-Authors: Chen Zhen

    Abstract:

    A study is performed about the water entry of a flat-Bottom Structure by use of the FE software MSC Dytran. The aim of the study is to find out the effect of the air cushion and structural mass on the impact peak pressure and the role of splash in the course of water entry. Some FE models are built up and some cases including the flat-Bottom Structure with different masses impacting water at some constant or initial velocities are calculated. The calculation shows that air plays an important role in the course of water entry of a flat-Bottom Structure and the compression of the air captured by the flat-Bottom Structure produces the first peak pressure. And the mass of the Structure has a great effect on the peak value of impact pressure. The Structure with different masses will produce different impact pressures even at the same impact velocity. Splash will occur a long time after the impact pressure reaches the peak value. A formula is given for the calculation of the peak value of impact pressure in this paper.

  • Prediction of slamming pressure on a flat-Bottom Structure by means of Neural Network
    Ocean Engineering, 2005
    Co-Authors: Chen Zhen

    Abstract:

    This paper discusses the issue about the prediction of the peak value of slamming pressure of a flat-Bottom Structure by means of Neural Network. At first we utilize the simulation software to calculate the slamming pressure of a flat-Bottom Structure entering water go as to form the data group for training the Neural Network. Then we discuss the different Structure forms of the network with different node numbers, compare the precision of different study rules and thus get the reasonable network form fit for the flat-Bottom Structure entering water system.