共查询到19条相似文献,搜索用时 515 毫秒
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中国先进研究堆冷中子源两相虹吸氢系统的概念设计及可行性试验 总被引:2,自引:1,他引:1
提出了中国先进研究堆冷中子源氢系统的概念设计方案,并进行了可行性试验。针对概念设计中采用的两相虹吸氢回路系统,使用氟里昂113进行了1:1的模化试验研究,确定了中子慢化室含气率、热虹吸系统循环能力及各部件的初步结构形式和尺寸。还进行了气泡在不同液体中上升速度的试验研究,以决定密度、粘度及表面张力等物性对气泡上升速度、含气率、系统循环能力的影响,分析得到模化关系,以便将氟里昂模化试验的结果应用于中国先进研究堆(CARR)堆冷中子源氢系统的设计。 相似文献
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《中国原子能科学研究院年报》2017,(0)
正中国先进研究堆(CARR)冷中子源装置采用单相液氘作为冷中子慢化剂,液氘慢化剂通过堆内装置热交换器热虹吸回路封闭式自然循环和氦气夹层内低温氦气(约19K)的冷却维持在液态。CARR冷中子源系统充氘调试主要目的为:1)实现首次氘装载、冷中子源冷态运行考验及带核综合试验,验证冷中子源系统满足合同规定的技术要求,能够安全稳定地运行;2)测量冷中子源热负荷、冷中子源运行模式运行参数验证以及冷中子 相似文献
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《中国原子能科学研究院年报》2017,(0)
正中国先进研究堆(CARR)冷中子源堆内部分由真空容器及堆内组件组成,包括热虹吸系统、主法兰和与冷中子源堆外系统的连接管线部分,称为冷源堆内装置。CARR冷中子源堆内装置安装在重水箱内,冷包及热虹吸回路装置安装在真空容器内,氘系统管线、氦制冷系统管线、真空管线在堆水池内需要安装固定并与冷包及热虹吸回路装置连接。冷包处在堆芯活性区中心标高位置。CARR冷中子源堆内安装具体流程如图1所示。冷中子源堆内安装具有难度大、精度高、技术 相似文献
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LIXiao-Ming BIQin-Cheng FENGQuan-Ke CHENTing-Kuan DUShe-Jiao 《核技术(英文版)》2004,15(4):243-247
To keep the void fraction of two-phase hydrogen in the moderator cell of the cold neutron source (CNS) of China Advanced Research Reactor (CARR) to a specified range, an annular vessel with the same size as the actual moderator cell was used as test section. Deionized water and alcohol, sucrose, and sodium chloride solutions with different concentrations were used as working fluid to find out influences of physical properties, such as density, viscosity and surface tension, of the two-phase mixture on void fraction. The tests proved that the ratio of surface tension to density of liquid phase has great influence on void fraction: the larger the ratio, the smaller the void fraction. Since the ratio of surface tension to density of Freon 113 is lower than that of liquid hydrogen, Freon 113 can be used as a working fluid to study the void fraction in the two-phase hydrogen thermosiphon loop in the CNS of CARR and the results will be conservative. 相似文献
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DUShe-Jiao BIQin-Cheng CHENTing-Kuan FENGQuan-Ke LIXiao-Ming 《核技术(英文版)》2004,15(6):375-380
The cold neutron source (CNS) is a facility to increase cold neutrons by scattering thermal neutrons in liquid hydrogen or deuterium around 20 K. For extracting a stable cold neutron flux from the CNS, the liquid quantity in the moderator cell should be maintained stably against disturbance of nuclear heating. The China Institute of Atomic Energy (CIAE) is now constructing the China Advanced Research Reactor (CARR: 60 MW). and designing the CARR-CNS with a two-phase thermo-siphon loop consisting of a condenser, two moderator transfer tubes and an annular cylindrical moderator cell. The mock-up tests were carried out using a full-scale loop with Freon-113,for validating the self-regulating characteristics of the loop, the void fraction less than 20% in the liquid hydrogen of the moderator cell, and the requirements for establishing the condition under which the inner shell has only vapor. The density ratio of liquid to vapor and the volumetric evaporation rate due to heat load are kept the same as those innormal operation of the CARR-CNS. The results show that the loop has the self-regulating characteristics and the inner shell contains only vapor, while the outer shell liquid. The local void fraction in the liquid increases with increasing of the loop pressure. 相似文献
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In certain natural-circulation reactor systems proposed recently, vapor generation takes place by flashing in an adiabatic riser above the core. A step-by-step facility design procedure was used to define suitable scaling criteria for a refrigerant-113 (R-113) experiment simulating the dynamics and stability of such a loop. The fact that vapor generation does not normally take place in the core allows additional flexibility in designing the model; almost perfect simulation can be achieved, mainly by reducing the height of the facility according to the liquid density ratio and scaling for similar void fraction distributions in the prototype and the model. 相似文献
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Experiments have been performed using sodium, water, white spirit and Freon 113 in a simple small-scale system, to determine the conditions necessary for gas entrainment inception at a vortex with an unstable gas core. The results demonstrate that surface tension effects play a major role and hence they must not be ignored when developing an entrainment-free system. 相似文献
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The three-dimensional moving particle semi-implicit (MPS) method is employed to simulate the deposition process of single droplet on the liquid film. The model accounts for the presence of inertial, gravitation, viscous and surface tension and is validated by comparison with experimental results. The parameters of liquid droplets and film are calculated by a one-dimensional mixture model in which correlations and methods on void fraction, entrainment fraction and droplet velocity and size distribution are employed. The simulation results are analyzed to study the effect of splash on the deposition and re-entrainment processes in annular-mist flow. It is found that splash plays an important role in the deposition and re-entrainment processes in high quality conditions of BWR. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(12):1078-1089
The purpose of the study is to develop a method for predicting steam carryunder which is one of the important characteristics of a steam separator. Bubbles returning to the liquid surface and trapped by the re-circulating flow are calculated by tracking the behavior of bubbles moving in liquid bulk where velocity and temperature distributions have been calculated beforehand in conjunction with the Monte-Carlo method. Regarding the statistics of bubbles, a survey of references and visual tests have been conducted. To validate this method, several tests to measure bubble behavior under air/water conditions at atmospheric pressure and high temperature and pressure ranging 3~7 MPa have been conducted with a full-scale steam separator. As a result, the developed method predicted with good precision the carryunder ratio obtained by the full-scale tests under the condition that carried-under void fraction was less than 20%, but underestimated carryunder ratio in the ATR “Fugen” reactor in which steam drum water level was shallow and average void fraction in water bulk was high. This method has a characteristic that carryunder ratio is underestimated in the case that void fraction is more than 20%. 相似文献
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Hideyuki Kudoh Dawei Zhao Ken-ichiro Sugiyama Tadashi Narabayashi Hiroyuki Ohshima Akikazu Kurihara 《Journal of Nuclear Science and Technology》2013,50(12):1175-1185
Little work on the void fraction behaviors along structural materials with poor-wettability for liquid metals has been performed. In the present study, void fraction behaviors around a single cylinder with non-wetting surface condition were quantitatively discussed by using a gas jet–cylinder system where the impinging jet flow, the boundary layer flow, the separation flow, and the wake flow appear. One cylinder with a non-wetting surface and two cylinders with a wetting surface were used to vary the wettability for liquid sodium, and void fraction distributions were measured around the cylinders. In the case of wetting condition, void fraction distributions around the cylinder decrease clearly in the backward region of the cylinder, and liquid-rich region is formed due to bubble separation from the cylinder surface. On the other hand, under non-wetting condition, because of two-phase flow without bubble separation on the cylinder surface, void fraction distributions show almost steady values around the cylinder compared to those with wetting surface. The void behaviors on a non-wetting surface were also confirmed by a visualization experiment conducted in water. The observed differences can be basically attributed to the work of adhesion required for liquid–solid interfacial separation. 相似文献
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The local void fraction, bubble size and interfacial area concentration for co-current air-water bubbly flow through a horizontal pipe of 50.3 mm internal diameter were investigated experimentally using the double-sensor resistivity probe method. The local and area-averaged void fractions and interfacial area concentrations were analyzed as a function of liquid and gas flow rates. These parameters were found to increase systematically with decreasing liquid flow and increasing gas flow. However, variations with the liquid flow were not as significant as with the gas flow. A consistent variation of the gas phase drift velocity and distribution parameter with the liquid flow rate was observed. It was demonstrated that presentation of the average void fraction in terms of flowing volumetric concentration was more appropriate for horizontal bubbly flow. Several bubble break-up mechanisms were discussed. It was concluded that average pressure fluctuations generated by the turbulent liquid fluctuations acting across a bubble diameter are the only mechanism which causes distortion of a bubble. Based on this force and the competing surface tension force, a theoretical model was developed for mean bubble size and interfacial area concentration. The theoretically predicted mean bubble size and interfacial area concentration were found to agree reasonably well with those measured by the double-sensor resistivity method. 相似文献
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Simultaneous measurement of void fraction and fundamental bubble parameters in subcooled flow boiling 总被引:1,自引:0,他引:1
Visualization was performed for the vapor bubbles in water subcooled flow boiling in a vertical heated tube to measure simultaneously the void fraction and the four fundamental bubble parameters: nucleation site density, bubble release frequency, bubble lifetime and bubble size. Using the mass flowrate and liquid subcooling as the experimental parameters, the changes of void fraction and bubble parameters with the wall heat flux were measured. The results of image analysis showed that the vapor void fraction could be approximated by the function of nucleation site density and bubble lift-off diameter; the bubble lift-off diameter was more influential than the nucleation site density. It was hence concluded that the bubble lift-off diameter could be regarded as the key parameter to determine the vapor void fraction under the present experimental conditions. The strong relation of bubble lift-off diameter to superheated liquid layer thickness was indicated for the future model development studies of bubble lift-off diameter. 相似文献