共查询到18条相似文献，搜索用时 140 毫秒
1.
随着陆地资源的日益短缺，深海矿产资源将成为人类未来社会经济可持续发展的重要保障。采集装置作为深海采矿系统的重要组成部分，不仅要解决采集率问题还要关注采矿活动造成的环境扰动。基于康达效应与CFD方法，获取采集装置不同运动状态下的流场数值模拟结果，精细划分流场内部结核各运动阶段的迁移状态，并使用射流角度与凸曲面壁半径控制变量，探讨采集装置参数对流场特征的影响，进而优化采集装置参数匹配。结果表明：1) 采集装置射流角度和凸曲面壁半径的增大，增加了流场均匀度，使得动能更集中于底部区，采集装置运动速度的增加会增强凸曲面壁下康达效应，当速度为0.5 m/s时，内部流场较为稳定；2) 采集装置射流角度、凸曲面壁半径与结核升力指数和曳力存在显著相关性，一定范围内，升力指数随着采集装置射流角度变大或凸曲面壁半径变小而升高；3) 分析对比结核运动阶段中迁移变化，当采集装置离底高度为80 mm，射流角度为45°，凸曲面壁半径为350 mm，采集装置运动速度为0.5 m/s时，结核能够精准进入吸入口。研究结果可为深海多金属结核采集装置的设计与研发提供重要参考。 相似文献
2.
随着新能源等新兴产业的高速发展，金属矿产资源需求激增，国内外争相发展深海采矿技术。基于竖轴漩涡的水动力特性，设计了一种带有4个切向射流喷嘴的吸盘式水力集矿装置，提出应用切向射流在集矿装置内诱导生成竖轴漩涡的新集矿方法。开展水力集矿模型试验，研究竖轴漩涡集矿流场流速分布特征；分析低、中、高3种旋流度流态下，集矿流量对矿粒运动轨迹和采集率的影响。结果表明：矿粒起动轨迹随着旋流度的增加，逐渐从混乱无序转向明显的圆周运动；在特定集矿流态下，矿粒采集率随集矿流量的增加不断提高；当矿粒采集率超过90%时，集矿流量需求随着旋流度的增加而减小。通过采矿车原理样机水池测试，初步验证了集矿装置的集矿性能，可为集矿装备的设计研发与论证提供借鉴。 相似文献
3.
深海蕴藏着丰富的多金属结核资源，受海水深度等限制，结核采集目前仍存在巨大挑战。水力式采矿具有结构简单、可靠性高的优势，是目前最具发展前景的采集方式之一。水力式采矿通过水流动力进行结核采集，喷射形成的复杂流场结构直接影响海床上结核颗粒剥离、起动、采集效率和海洋环境扰动强度，采集器离地高度、喷嘴射流角度和速度等具有较大优化空间。基于计算流体力学数值模拟研究了集矿头附近三维水流结构，分析了喷嘴射流速度和结核粒径对局部流场、床面剪切力以及结核采集能效的影响。结果表明：集矿头周围流场存在典型分区结构，包括淹没射流区、冲击区、壁面射流区、汇合区和上升区；随着喷射流速增大，最大床面剪切力近似线性增长，结核有效起动面积指数增长；随着结核粒径增大，有效起动面积减小，结核采集能效降低；综合考虑结核采集强度和采集能效，建议采集器喷射流速取8～9 m/s。 相似文献
4.
超声多普勒测量海底渗漏气泡流速的实验研究 总被引：1，自引：0，他引：1
海底渗漏气泡流速是测量海底冷泉渗漏气体流量的主要参数。为了测量海底渗漏气泡流速,利用超声多普勒测量的原理和气泡的二次多普勒效应,提出海底渗漏气泡速度的超声多普勒测量方法。超声多普勒测量根据超声多普勒原理设计了气泡流量测量装置,通过多普勒频移算出海底渗漏气泡流速,同时用视频法测出海底渗漏气泡流速。从多普勒法和视频法的气泡速度数据t分布95%的置信水平误差可知,视频法的气泡速度数据的波动大于多普勒法的气泡速度数据的波动,表明了超声多普勒测量海底渗漏气泡流速的有效性和准确性,优于视频法测量海底渗漏气泡流速。 相似文献
5.
基于图像处理技术的养殖池集污特性研究 总被引：2，自引：0，他引：2
本文针对养殖池的集污试验,研究了用于量化分析污物聚集面积的图像处理技术,并将其用于方形圆切角养殖池在边侧管式射流方式下的集污特性研究。图像处理技术包括图像预处理、图像增强、图像分割、轮廓提取四个步骤,成功获得了污物的量化分布面积。在养殖池集污特性研究方面,本文研究了射流流速为24cm/s条件下,不同射流角(射流方向与池壁夹角)对污物聚集效果的影响。结果表明,方形圆切角养殖池存在一个最优的射流角度,本文研究条件下,最优角度约为40°。本文研究结果,可为养殖池水力驱动优化布置提供参考。 相似文献
6.
为使深海采矿作业更为高效、环保，提出了一种用于深海采矿的循环式水力集矿系统设计方案。该系统主要由集矿头、矿-沙分离器、水-沙分离器、水泵以及连接各部件的管道组成。采用基于欧拉法的液固两相流计算模型对该系统的关键问题，即矿-沙分离器和水-沙分离器的泥沙颗粒流动进行数值研究。相间拖曳力采用Richardson-Zaki模型。液相与固相湍流分别采用标准k-ε模型和Tchen湍流响应模型。该模型经验证对于直径0.165 mm与0.27 mm细颗粒具有较高精度。利用该模型，以0.165 mm泥沙颗粒为例，得到了两种分离器的分离效果与入口流速之间的规律，分析了两者颗粒浓度分布与流场特征。结果表明，两种分离器的性能均与入口流速有关，在选取适当入口条件时均可取得良好效果。 相似文献
7.
海底输油管线是海洋油气田开发的生命线工程,在复杂的海洋环境中易发生破坏.为使管线实现自埋防护,提出用柔性材料代替刚性导流板安装在管线顶部,不仅可以增加阻水面积,加大冲刷深度和范围,而且可以减缓刚性导流板对管线上部水流的扰动强度和尾流涡旋的扰动强度,减小管线的振动.利用力学关系由变形方程推导出海底管线与海底间距离为零以及不为零情况下柔性导流板变形的二次曲面方程和自由端最大挠度.在单向流条件下将不同材料不同长度的柔性导流板安装在管线中轴上方开展试验研究,测量柔性导流板在水流作用下的变形曲面.对比分析利用公式计算柔性导流板的自由端最大挠度和曲面变形数据与试验结果,发现两者吻合较好. 相似文献
8.
对挡潮闸枢纽中矩形中孔、底孔鱼道中紊流结构进行了较为系统的试验研究,并做了放鱼试验。选择了一种鱼类偏爱流速所对应的流量作为典型流量,考虑了不同的孔口位置(中孔和底孔),用声学多普勒测速仪(ADV)量测了测点的三维瞬时流速及流向,分析了矩形孔口鱼道的三维时均流速分布特征、断面最大流速沿程变化规律、流速矢量场、紊动强度分布及雷诺应力分布。此外,还通过放鱼试验,利用在鱼体植入T形标签和高速摄影机观察了过鱼对象对中孔、底孔的反应情况,分析了过鱼对象与矩形孔口鱼道紊流结构的关系。试验结果表明:水流经中孔形成三维紊动自由射流,经底孔形成三维壁面射流,中孔纵向流速呈高斯分布,而底孔纵向流速则近似为高斯分布,流速由孔口向两侧逐渐减小;中孔和底孔横向流速在位于孔口范围内的纵剖面上沿程减小,孔口之外则变化较小;中孔和底孔垂向流速分布特征表现为在铅垂方向上均存在旋涡;在中孔水平面和纵剖面上,纵向最大流速均沿程衰减;中孔和底孔情形孔口处紊动强度和雷诺应力比非孔口处大得多,而非孔口处不同水深平面上紊动强度和雷诺应力变化趋于平缓;过鱼对象喜爱在紊动强度分布的峰值区和雷诺应力较大变幅区溯游。 相似文献
9.
采用超声水位和PIV流速测量技术,对不同水力坡度下非淹没丁坝近区的水流结构进行了试验研究。结果表明,随着水力坡度的降低,在坝头处,紊动强度较大的区域逐渐向主流区及上游扩散;在坝后,跌水最低点逐渐下移,漩涡中心向丁坝侧边壁靠近。回流区长度与宽度的变化和水力坡度的变化无明显对应关系,但坝头近壁区的流速与坝后回流区的长度及宽度存在高度响应的线性关系。研究成果揭示了丁坝在不同水力坡度下调整水流结构的机理,同时对各家测量得到的回流区长度不等有了较明确的答案,为工程中丁坝的设计及河道岸线的规划提供了科学依据。 相似文献
10.
针对管线绕流剪切层区的水流特征,利用射流分析的类似方法,通过简化控制方程,从理论上探讨了剪切层区的时均速度分布规律。物理试验中采用ADV测速仪对回流区流场进行了测量,对各流区流速和紊动强度变化趋势进行了讨论,并将试验结果与理论推导进行对比,二者基本吻合,为进一步研究海底管线防护措施提供了理论依据。 相似文献
11.
The megabenthos plays an important role in the abyssal ecosystem. The holothuroids have been proposed as indicators of physical disturbance of the seabed caused, for example, by commercial deep-sea mining of manganese nodules. Environmental studies at seabed mining claims have resulted in numerous still photographs that provide an overview of the megabenthos in manganese nodule fields. Data from these investigations and from the large-scale disturbance and recolonization experiment DISCOL have been used to summarize knowledge of the taxonomy and ecology of holothurians at manganese nodule sites. 相似文献
12.
文章旨在确定深海多金属结核的物理特性，并分析其对采输过程的影响，以指导工程应用。总结了深海多金属结核开采的最新研究进展，通过对数据进行统计整理、回归分析，确定了结核形成机理及主要成分、在海底的分布特性、结核形态及构造、结核尺寸与重量关系、含水量、密度、孔隙特性及结核强度等关键物理特性。研究表明：结核形状多样，质松多孔隙，含水率高，近似均匀分布在海床上或浅泥层中。颗粒质量和尺寸联合概率分布具有长右尾特性，需使用更广义的联合概率密度函数copula才能准确建模。结核抗拉强度随结核直径增大按对数函数递减。此外，深海高压环境下结核的开采需更多能耗，且结核表现出更高的延性。结合固液两相流分析和颗粒沉降理论，分析了结核形状、尺寸、密度等主要参数对水力举升过程的影响，确定了颗粒破碎的主要方式和规律，总结了不同粒径级配输运造成堵塞的可能原因。 相似文献
13.
深海采矿尾矿排放产生的细颗粒羽状流会对海底生态环境造成影响，预测尾矿排放羽状流行为及其对环境影响具有工程意义。基于欧拉多相流方法，采用欧拉双流体模型对深海采矿细颗粒羽状流开展数值模拟研究，分析近海底排放的羽状流演化和发展过程，探究羽状流初始排放质量浓度、排放速度对羽状流扩散过程的影响。结果表明：初始排放条件对羽状流演化性质有重要影响。主射流区被稀释的程度随着初始入射速度的增大而减小，随着入射质量浓度的增大而增大；初始羽状流入射速度和质量浓度越大，撞击海底后的水平方向流动速度越快，影响区域越广；水平速度的峰值随着初始入射速度的增大呈对数增长；当初始质量浓度和速度高于50 g/L和 0.5 m/s 时可能会导致颗粒在海底撞击点附近堆积成坡状，影响底流的后续发展。研究结果可以为深海采矿尾矿排放参数选择提供参考。 相似文献
14.
Quantitative estimation of seafloor features from photographs and their application to nodule mining
Rahul Sharma 《Marine Georesources & Geotechnology》2013,31(4):311-331
Methods developed for quantitative estimation of seafloor features from seabed photographs and their application for estimation of nodule sizes, coverage, abundance, burial, sediment thickness, extent of rock exposure, density of benthic organisms, and their lebensspuren have been presented. Digitization of the photographs shows variable nodule size (< 1 to 10 cm), coverage (< 1 to 75%) and abundance (< 1 to 20 kg/m2). Nodule population is inversely proportional to the coverage of the sediment (10–100%) and its thickness (0 to > 10 cm), which causes differential burial (0–100%) of nodules. Correlation between nodule parameters (diameter and coverage) in the photographs and grab recovery is used to evolve empirical relationships for estimating nodule abundance in different seabed settings. The rock outcrops (basalts) with a coverage of 6–100% are the sources of nuclei for the nodules, the distribution of which is controlled by the local topography. Higher concentrations of nodules are observed along the slopes, followed by the crests of seamounts, and are lowest in the valleys and plains. A population density of 6–7 benthic organisms per 100 m2 belonging to 7 different phyla is observed, with a high frequency of lebensspuren (4–12 traces/m2) in association with nodules. Estimation of these parameters can be used as important inputs in the design of the nodule collector, as it will have to encounter a variety of seafloor conditions, such as patchy nodule distribution, rock outcrops, steep slopes, and frequent microtopographic changes, as well as benthic life. The distribution and relation of various features with one another can also be used to understand the possible impact of nodule mining on the seabed. Estimates show that for a yield of 3 million tonnes of nodules per year, the volume of sediment disturbed will be between 200 × 107 and 500 × 107 m3over an area of 300–600 km2, depending upon the average abundance of nodules. Hence, the nodule collector will have to be a self‐propelled system, with photographic and acoustic sensors, to enable selective mining and avoid unfavorable areas. 相似文献
15.
By utilizing characteristic interaction processes of nuclear radiation with matter and by applying automatic data acquisition and reduction methods, various analytical problems encountered in mining and processing of manganese nodules can be solved. Development work performed at the Geesthacht research center demonstrates thatgamma -ray transmission spectrometry allows a reliable quasi-continuous and nondestructive determination of both the nodule drift velocity and the space concentrations of nodules, sediment, and water in a conveyer flow. Such data are representative of the efficiency of collector or hydraulic lift systems and are of considerable importance in economy deliberations. Measuring devices have been designed which may be attached to a conveyer pipe in the deep sea. For elemental analyses of manganese nodules, a rapid nuclear method based on fast-neutron activation techniques has been developed that allows determinations of the most relevant metals without sample treatment, thus being particularly suited for quasi-continuous applications. 相似文献
16.
A seabed instrument called Lancelot has been developed to measure pore pressure characteristics within potentially unstable marine sediment deposits, in any water depth. An estimate of the coefficient of consolidation can be obtained from the sediment pore pressure dissipation response that occurs following penetration into the seabed. This data can be used to calculate the coefficient of hydraulic conductivity, which is useful in analyzing the seepage velocity of pore fluids moving within the sediment mass. Pore-water pressures in excess of the normal hydrostatic profile are detected and used in static and dynamic liquefaction analyses, with a view toward understanding the origin of unusual seabed features such as pockmarks, as well as short-term instability caused by wave loading. An example of static liquefaction due to seepage stress is given for sites in and adjacent to the well-known 1929 Grand Banks debris flow, along with an example of incomplete liquefaction caused by dynamic wave loading within Miramichi Inner Harbor, New Brunswick. The adoption of in situ measurement techniques is shown to produce data of a quality not normally obtainable from recovered core samples, due to pressure relief and sampling disturbance effects. 相似文献
17.
B. J. Lees 《Geo-Marine Letters》1981,1(3-4):249-254
A method is described to calculate the relationship (β) between the eddy diffusivity of suspended particles and the eddy viscosity
of the fluid. The data were obtained while making suspended sediment concentration measurements near the seabed on the British
continental shelf. β was calculated for 0.50 size fractions and varies inversely with the suspended sediment concentration.
The values were used successfully to calculate suspended sediment transport rates for separate sand fractions through a spring
tidal cycle. Finally, specific values of β are suggested for varying concentrations of sand at a reference height of 100 cm
above the seabed. 相似文献
18.
Chan-Young Park Seung-Ho Park Choon-Woo Kim Jung-Keuk Kang Ki-Hyune Kim 《Marine Georesources & Geotechnology》1999,17(4):371-386
In order to develop the mineral resources contained in manganese nodules of the deep sea, the Korea Ocean Research & Development Institute (KORDI) has explored the area allocated by the United Nations in the Clarion-Clipperton Fracture Zone in the northeastern Pacific. During research cruises, the seabed surface was photographed every 30 s by the KORDI Deep Tow Imaging System (DTIS). Features such as the coverage and size distribution of manganese nodules on the photographs serve as the essential information to determine the potential mining areas. This article presents (semi)automatic procedures to extract the useful features from the photographs of the seabed surface using digital image processing techniques. The 35-mm films are first digitized by the film scanner. The depth information written on the film is then recognized to compensate for distortions due to nonuniform illumination. The nodule areas on the digitized image are recognized and separated from the background based on the characteristics of the nodules. The nodule coverage and distribution of nodule diameters are then calculated from the processed image. The proposed technique has been applied to sample photographs of the seabed surface. Experimental results indicate that the technique could be utilized as an efficient tool to process the massive collection of photographs of the seabed surface. 相似文献