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养鱼污水进行处理后再循环回用于养鱼对防止养鱼污水的污染和节省水资源均具有重要意义,但目前尚未见相应的国家和行业标准。本文通过文献调研,并结合相关标准,特别参考《渔业水质标准》,提出了养鱼循环水回用的水质标准。考虑到铝盐絮凝剂的使用,本文还提出了铝的指标限制。 相似文献
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Chang Kyu Rheem Hajime Yamaguchi Hiroharu Kato 《Journal of Marine Science and Technology》1997,2(2):101-121
A new model, called the distributed mass/discrete floe model, is proposed for performing practical computations of mesoscale
pack ice rheology. This model possesses the advantages of both the continuum and the discrete element models: it can express
the discrete nature of pack ice, for which it is difficult to use a continuum model, and requires a much shorter computation
time than a discrete element model. The pack ice is divided into ice bunches in which the floes, assumed to be distributed
uniformly, are modeled as inelastic disks or rectangles floating on the water. The ice interaction forces are formulated from
the relationship between the impulse on the bunch and the variation of momentum in the bunch. The ocean flow is calculated
simultaneously with the floe movement using a multilayer model. In a circulating water channel, drift tests of physical model
floes were performed in order to investigate the characteristics of their motion and interaction with ocean structure models.
Near the structure, the floe motion depends on the floe shape. Disk floes show a lateral motion in front of the structure.
They flow out around both sides of the structure and the number of floes in front of the structure decreases with the lapse
of time. On the other hand, rectangular floes scarcely flow laterally. The number of floes in front of the structure remains
constant over time. These experiments indicate that when the motion of pack ice around a structure is simulated, it is important
to consider the floe shape. The disk floe motion and the rectangular floe motion can be regarded as extreme cases of pack
ice motion. Actual pack ice motion may be between these two extremes. Computations were carried out using the distributed
mass/discrete floe (DMDF) model. Simulation results were compared with the circulating water channel experiment results and
sea ice motion in the southern part of the Sea of Okhotsk. The DMDF model predicted the circulating water channel drift test
results quite closely. The DMDF model results also compared quite well with the sea ice motion. 相似文献
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针对轨道吸污装置吸污能力不足和污染周边环境的问题,提出吸风循环吸污的解决方案,即将吹风机产生的全部风量仅供给一侧吹嘴吹风吸污,将吸风机产生的排风供给另外一侧吹嘴吹风吸污,形成吸风机排风的循环利用,并通过调节风门开启的大小,调节吹风的风量和风速,从而增强轨道吸污装置吹风吸污的效果.基于流体力学,在忽略空气黏性力和密度变化以及不同流速气体混合时能量损失的前提下,对按照解决方案改进得到的吸风循环式轨道吸污装置吸污能力及能耗进行分析计算.结果表明:在作业速度为10 km· h-1时,吸风循环式轨道吸污装置能够吸净单层粒径分别达5 mm的铁屑和14.3 mm的石子;相比改进前的轨道吸污装置,吸收污物的最大粒径提高了7倍左右,污物吸净率高于98%;吸污作业功率节省74 kW,能耗下降2o%. 相似文献
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环形水槽机理与应用研究 总被引:4,自引:0,他引:4
通过对环形水槽水流测试,得出流速垂向和径向分布.依据泥沙动水沉降试验,分析横向流对泥沙沉降影响,指出环形水槽应用前景。 相似文献
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循环水槽同传统拖曳水池相比具有许多优点,因而日益广泛地应用于船型开发和船舶水动力性能研究。在水槽中设置隔板可以模拟海洋中的分层流,但隔板的迟滞作用必然会对循环水槽计测部流场品质造成一定的影响。为了研究这一设想对流场的影响,数值模拟循环水槽在无隔板、整段隔板以及分段隔板情况下的流动情况。对比结果表明,采用分段隔板形式较为理想。另一方面,循环水槽作为一种基础实验设施,对其计测部的水平度有着严格要求,探讨安装中的误差或投入使用后地基沉降引起的水槽倾斜对计测部流动带来的影响。基于VOF模型,模拟水平及各倾角二维条件下循环水槽计测部的流动情况,结果表明,较大倾角时,计测部波面变化较大,且计测部末端有气泡产生,而在微小倾角时,波面变化不明显。 相似文献