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以用于RnR模型验证的气溶胶再悬浮试验的设计参数及条件为基础,利用GASFLOW程序构建分析模型进行模拟计算,并与RnR模型的计算结果和试验数据进行对比。研究结果表明:在发生再悬浮的主要阶段,GASFLOW能较好地模拟气溶胶再悬浮行为;在较低气流速度的条件下,RnR模型分析结果更接近试验数据;在较高气流速度的条件下,GASFLOW再悬浮模型分析得出的结果更加保守。为提升计算结果的准确性,建议加入对黏附力概率分布特性的考虑,并进一步研究在GASFLOW中开发RnR模型的可行性。 相似文献
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事故工况下,安全壳内已经沉降的气溶胶由于气流扰动等原因可能发生再悬浮现象,文章中基于STORM(Simplified Test Of Resuspension Mechanism)实验结果对气溶胶再悬浮力学平衡模型适用性进行评估。针对实验建立分析模型,研究了Wichner力学平衡模型中扰动力系数、沉积表面粗糙度和Michael力学平衡模型中沉积表面微凸体之间的距离的影响。通过对比分析模型预测结果与实验测量结果,评估模型的适用性。结果表明:Wichner力学平衡模型更适用于预测气溶胶粒径较小时,较大扰动气流速度区间内的再悬浮行为。 相似文献
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利用中国原子能科学研究院开发的CABSA程序气溶胶再悬浮模块中的ECART模型,对STORM项目的SR11试验进行计算,分析了核电厂严重事故下的气溶胶再悬浮特性。结果表明:气溶胶所受各种力均随直径的增大而增大,其中使气溶胶悬浮的拖曳力和爆发力比使气溶胶附着在结构表面的黏着力和重力增长更快;直径大的气溶胶悬浮率更大;结构表面流体速度能够影响拖曳力和爆发力,速度增大会提高拖曳力和爆发力,最终导致悬浮率增加。利用该特点,可通过降低结构表面流速降低拖曳力和爆发力,从而减小悬浮率,最终减小裂变产物向空间的重新释放。 相似文献
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湍流模型对安全壳内氢气浓度场模拟的影响 总被引:1,自引:1,他引:0
利用计算流体力学程序FLUENT和GASFLOW研究了不同湍流模型下,氢气在安全壳内的传输与混合过程。计算结果表明:RNG k-ε模型能够得到较合理的结果,它能够较好的模拟氢气的质量扩散,动量扩散和湍流特征;FLUENT标准k-ε模型、标准k-ε模型和GASFLOW中k-ε模型能够在氢气浓度场分布上得到与RNGk-ε模型基本一致的结果,但由湍流导致的各种流动参数的波动不能在前三个模型中得到满意的模拟;GASFLOW中代数模型没能较好的模拟氢气的质量扩散和动量扩散,氢气的浓度场分布与其他模型的计算结果存在较大的差别。因此,选择合适的湍流模型,对于研究严重事故下安全壳内的氢气分布有重要的意义。 相似文献
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严重事故下安全壳内氢气浓度场分布 总被引:3,自引:2,他引:1
利用计算流体力学程序FLuENT和GASFLOW,采用不同的湍流模型,研究了核电站严重事故下氢气在安全壳内的传输与混合过程.计算结果表明,FLUENT中的RNG k-ε模型能够较好的模拟氢气的质量扩散,动量扩散和湍流脉动特征;FLUENT中的标准k-ε模型和GASFLOW中的k-ε模型能得到工程上可以接受的计算结果;而GASFLOW中代数模型未能较好地模拟氢气的质量扩散和动量扩散,氢气的浓度场分布与其他模型的计算结果存在较大的差别.同时,本文对混合气体中的水蒸汽浓度和气体的质量流速对安全壳内氢气浓度分布的影响进行了初步研究.研究表明,破口气体的密度和流速是影响氢气浓度场的重要因素;混合气体密度越小、流速越大,则有更大的浮力和初始动量作用于气体.湍流模型的选择和对浮力驱动的湍流射流的模拟是影响严重事故下氢气在安全壳内的分布模拟结果的重要因素. 相似文献
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利用计算流体力学程序FLUENT和GASFLOW,采用不同的湍流模型,研究了核电站严重事故下氢气在安全壳内的传输与混合过程。计算结果表明,FLUENT中的RNGk-ε模型能够较好的模拟氢气的质量扩散,动量扩散和湍流脉动特征;FLUENT中的标准k-ε模型和GASFLOW中的k-ε模型能得到工程上可以接受的计算结果;而GASFLOW中代数模型未能较好地模拟氢气的质量扩散和动量扩散,氢气的浓度场分布与其他模型的计算结果存在较大的差别。同时,本文对混合气体中的水蒸汽浓度和气体的质量流速对安全壳内氢气浓度分布的影响进行了初步研究。研究表明,破口气体的密度和流速是影响氢气浓度场的重要因素;混合气体密度越小、流速越大,则有更大的浮力和初始动量作用于气体。湍流模型的选择和对浮力驱动的湍流射流的模拟是影响严重事故下氢气在安全壳内的分布模拟结果的重要因素。 相似文献
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Based on the design parameters and conditions of the aerosol resuspension test for the validation of the RnR model, an analysis model was built by using GASFLOW code for calculation and simulation, and the results were compared with the calculation results of RnR model and the test data. The study results show that GASFLOW can simulate aerosol resuspension well in the main stage of resuspension. Under the condition of lower air velocity, the analysis results of RnR model are closer to the test data. Under the condition of higher air velocity, the results of GASFLOW model are more conservative. In order to improve the accuracy of the calculation results, it is suggested to consider the probability distribution characteristics of adhesion, and carry out further study on the feasibility of developing RnR model in GASFLOW. 相似文献
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Utilizing ECART model in resuspension module of CABSA code developed by China Institute of Atomic Energy, the SR11 test in STORM project was calculated and the features of aerosol resuspension under severe accident of nuclear power plant were analyzed. The result shows that all the forces on aerosol increase with aerosol diameter, drag force and burst force increase faster than adhesive force and gravity force. Aerosol with larger diameter has greater resuspension rate. Fluid velocity above structure can affect drag force and burst force, the increment of velocity can enlarge both the forces, and make the resuspension rate increase. By taking this advantage, the drag force and burst force can be reduced by reducing the fluid velocity above structure, and finally decrease the release of fission product to the environment. 相似文献
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The graphite dust generated in an HTR/PBMR during normal reactor operation is deposited inside the primary system and becomes radioactive due to sorption of fission products. A significant amount of radioactive dust may be resuspended and released to the environment in case of LOCA. Therefore accurate particle resuspension models are required for HTR/PBMR safety analyses.Thermal-hydraulic safety analyses of HTR/PBMR type reactors are typically performed using computer codes such as FLOWNEX, MELCOR, or SPECTRA. None of these codes currently includes a well-tested mechanistic resuspension model.The resuspension model based on the Vainshtein model has been developed and implemented into the SPECTRA thermal-hydraulic system code. The resuspension model formulation has been extended in such way that other formulations, for example the Rock’n Roll model, may easily be defined and used within the general model framework.Several test calculations were performed, including comparisons of the numerical SPECTRA results with the analytical solutions obtained by means of MathCAD. Furthermore, comparisons with the experimental results of the Reeks and Hall, and STORM experiments were made. It was concluded that the model gives satisfactory results for a number of tests. 相似文献
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This study was conducted as part of the construction of an integrated system to mechanistically evaluate flame acceleration characteristics in a containment of a nuclear power plant during a severe accident. In the integrated analysis system, multi-dimensional hydrogen distribution and combustion analysis codes are used to consider three-dimensional effects of the hydrogen behaviors. GASFLOW is used for the analysis of a hydrogen distribution in the containment. For the analysis of a hydrogen combustion in the containment, an open-source CFD (computational fluid dynamics) code OpenFOAM is chosen. Data of the hydrogen and steam distributions obtained from a GASFLOW analysis are transferred to the OpenFOAM combustion solver by a conversion and interpolation process between the solvers. The combustion solver imports the transferred data and initializes the containment atmosphere as an initial condition of a hydrogen combustion analysis. The turbulent combustion model used in this study was validated by evaluating the F22 test of the FLAME experiment. The coupled analysis method was applied for the analysis of a hydrogen combustion during a station blackout accident in an APR1400. In addition, the characteristics of the flame acceleration depending on a hydrogen release location are comparatively evaluated. 相似文献
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Analysis of steam and hydrogen distributions with PAR mitigation in NPP containments 总被引:1,自引:0,他引:1
P. Royl H. Rochholz W. Breitung J. R. Travis G. Necker 《Nuclear Engineering and Design》2000,202(2-3)
The 3-D-field code, GASFLOW is a joint development of Forschungszentrum Karlsruhe and Los Alamos National Laboratory for the simulation of steam/hydrogen distribution and combustion in complex nuclear reactor containment geometries. GASFLOW gives a solution of the compressible 3-D Navier–Stokes equations and has been validated by analysing experiments that simulate the relevant aspects and integral sequences of such accidents. The 3-D GASFLOW simulations cover significant problem times and define a new state-of-the art in containment simulations that goes beyond the current simulation technique with lumped-parameter models. The newly released and validated version, GASFLOW 2.1 has been applied in mechanistic 3-D analyzes of steam/hydrogen distributions under severe accident conditions with mitigation involving a large number of catalytic recombiners at various locations in two types of PWR containments of German design. This contribution describes the developed 3-D containment models, the applied concept of recombiner positioning, and it discusses the calculated results in relation to the applied source term, which was the same in both containments. The investigated scenario was a hypothetical core melt accident beyond the design limit from a large-break loss of coolant accident (LOCA) at a low release location for steam and hydrogen from a rupture of the surge line to the pressurizer (surge-line LOCA). It covers the in-vessel phase only with 7000 s problem time. The contribution identifies the principal mechanisms that determine the hydrogen mixing in these two containments, and it shows generic differences to similar simulations performed with lumped-parameter codes that represent the containment by control volumes interconnected through 1-D flow paths. The analyzed mitigation concept with catalytic recombiners of the Siemens and NIS type is an effective measure to prevent the formation of burnable mixtures during the ongoing slow deinertization process after the hydrogen release and has recently been applied in backfitting the operational German Konvoi-type PWR plants with passive autocatalytic recombiners (PAR). 相似文献