中国先进研究堆堵流事故分析

堵流事故是板状燃料研究堆发生概率相对较高的一种事故。本文进行CARR堵流事故分析时,假定额定功率运行下,1盒燃料组件的入口全部堵塞。用Relap5\Scdapsim\Mod3．2程序分析堵流事故时反应性、堆功率、压力、流量和温度等的变化,并分析发生堵流的标准燃料组件对周边燃料组件的影响。结果表明,发生堵流的燃料组件将烧毁,但不向相邻的组件扩展。CARR设计采取的安全措施可以把堵流事故后果控制在可接受范围之内。     

低压铸造流动与传热耦合计算的研究

根据低压铸造充型流动的特点 ,利用计算机数值模拟技术 ,对低压铸造充型阶段的流动怀传热过程进行了耦合计算 ,从而保证了模拟结果的准确性和可靠性。在此基础上开发出了模拟软件 ,并对实际低压铸件进行了模拟分析 ,结果与实际生产情况吻合很好     

Tree-shaped flow structures designed by minimizing path lengths

This paper outlines a direct route to the construction of effective tree-shaped flow structures. Dendritic flow structures dominate the design of natural and engineered flow systems, especially in thermal and fluid systems. The starting point is the optimization of the shape of each elemental area or volume, such that the length of the flow path housed by the element is minimized. Proceeding toward larger and more complex structures - from elements, to first constructs, second constructs, etc. - the paper develops tree-shaped flow structures between one point and a straight line, one point and a plane, a circle and its center, and a point and many points distributed uniformly over an area. In the latter, the construction method is applied to a fluid flow configuration with laminar fully developed flow. The constructions reveal several features that are supported by empirical observations of natural tree-shaped flows: asymmetry, flow rate imbalance, pairing or bifurcation, angles between branches, and Y-shaped constructs that lie in a plane. It is shown that these basic features are necessary because of “packing”, i.e., assembling optimized elements into a fixed space, and filling the space completely. For the flow between an area and one point, the best elemental shape is the regular hexagon. It is shown that the emergence of string-shaped links that connect two or more elements are necessary features, which are also required by packing. Strings cover some of the inner zones of the tree network, particularly the inner zones of large and complex trees. Dichotomous Y-shaped constructs dominate the tree structure, especially the peripheral zones of the tree canopy. The practical importance of the simplified design method is discussed.     

砾岩油藏合理注采压力系统研究--以七中东区八道湾组油藏为例

注采压力系统指的是从注水泵站到采油井井口的各环节的压力配置 ,在这一压力系统中 ,地层压力和油井流动压力是决定整个压力系统的关健 ,也是油藏工程研究的核心。本文利用油藏工程方法对砾岩油藏高含水期油井和注水井的地层压力、流动压力等注采压力系统进行了研究界定 ,将为砾岩油藏的开发水平提供技术支持     

受约束且TCP友好的拥塞控制研究

提出了一种使用RTP／RTCP来收集信息的TCP友好的流控算法。当前的多媒体源对发送速率能够调整的粒度和上下限都有要求。本文提出的算法不仅满足了流控算法的TCP友好（TCP－friendly）的特性，还考虑了多媒体源的这些限制。提出的流控算法能够调整的步长是阶梯的。最后还对TCP友好的流控算法和它的约束算法进行了仿真，并分析了结果。     

大型水平输气管线优化设计新方法

提出了含进分气点的水平输气管线优化设计新方法，该方法对于传统的优化思想进行了改进，概念清晰，方法简便，同时，将遗传算法引入输气管线的优化设计中，与常规的优化方法相比，具有明显的优越性。     

Modelling of a gas flow measurement: Application to nuclear containment vessels

The objective of this work is to simulate the gas flow across a concrete wall of a nuclear power plant internal enclosure. In the laboratory, permeability measurements are generally made on cylindrical samples (15 cm diameter×5 cm height: ∅ 15×5 cm) with a steady-state experiment. To be able to predict structural behaviour, we studied size effect and steady-state time with a modified CEMBUREAU permeability test. A statistical approach showed that there is no size effect on concrete permeability. Laboratory results found on cylindrical samples can be applied to tests in situ, where concrete specimens are thicker. A model based on the mass balance relation provided times to reach steady state and reproduced experimental flow kinetics for uniform water content across specimens.     

CALCULATION ON TWO-PHASE FLOW TRANSIENTS AND THEIR EXPERIMENTAL RESEARCH

From basic equations of gas-liquid, solid-liquid, solid-gas two-phase flow, the calculating method on flow transients of two-phase flow is developed by means of characteristic method. As one example, a gas-liquid flow transient is calculated and it agrees well with the experimental result. It is shown that the method is satisfactory for engineering demand.     

LS SIMD微处理器中的三组指令并发执行的设计

文章介绍了LS SIMD微处理器中实现三组指令并发执行的可能性和必要性，分析了三组指令并发执行给流水线带来的影响，并讨论了控制逻辑对三级指令并发执行的控制及其实现形式。