The Water-Bearing Numerical Model and Its Operational Forecasting Experiments PartII: The Operational Forecasting Experiments

おhe water-bearing numerical model is undergone all round examinations during the operational forecasting experiments from 1994 to 1996. A lot of difficult problems arising from the model′s water-bearing are successfully resolved in these experiments through developing and using a series of technical measures. The operational forecasting running of the water-bearing numerical model is realized stably and reliably, and satisfactory forecasts are obtained.

Bearing splitting and near-surface source ranging in the direct zone of deep water

Sound multipath propagation is very important for target localization and identification in different acoustical zones of deep water. In order to distinguish the multipath characteristics in deep water, the Northwest Pacific Acoustic Experiment was conducted in 2015. A low-frequency horizontal line array towed at the depth of around 150 m on a receiving ship was used to receive the noise radiated by the source ship. During this experiment, a beating-splitting phenomenon in the direct zone was observed through conventional beamforming of the horizontal line array within the frequency band 160 Hz- 360 Hz. In this paper, this phenomenon is explained based on ray theory. In principle, the received signal in the direct zone of deep water arrives from two general paths including a direct one and bottom bounced one, which vary considerably in arrival angles. The split bearings correspond to the contributions of these two paths. The beating-splitting phenomenon is demonstrated by numerical simulations of the bearing-time records and experimental results, and they are well consistent with each other. Then a near-surface source ranging approach based on the arrival angles of direct path and bottom bounced path in the direct zone is presented as an application of bearing splitting and is verified by experimental results. Finally, the applicability of the proposed ranging approach for an underwater source within several hundred meters in depth in the direct zone is also analyzed and demonstrated by simulations.

Experimental Study on Hydrocarbon Formation Due to Reactions Between Carbonates and Water or Water Bearing Minerals in Deep Earth

In order to investigate the mechanism of formation of abiogenetic hydrocarbons at the depth of the Earth, experimental research on reactions between carbonates and water or water bearing minerals was carried out at the pressure of about 1 GPa and the temperature range of 800-1500℃. The reactions took place in an open and nonequilibrium state. Chromatographic analyses of the gas products indicate that in the experiments there were generated CH 4 dominated hydrocarbons, along with some CO 2 and CO. Accordingly, we think there is no essential distinction between free state water and hydroxy in the minerals in the process of hydrocarbon formation. This study indicates that reactions between carbonates and water or water bearing minerals should be an important factor leading to the formation of abiogenetic hydrocarbons at the Earth’s depth.

The Water-Bearing Numerical Model and Its Operational Forecasting Experiments Part I: The Water-Bearing Numerical Model

In first paper of articles, the physical and calculating schemes of the water-bearing numerical model are described. The model is developed by bearing all species of hydrometeors in a conventional numerical model in which the dynamic framework of hydrostatic equilibrium is taken. The main contributions are: the mixing ratios of all species of hydrometeors are added as the prognostic variables of model, the prognostic equations of these hydrometeors are introduced, the cloud physical framework is specially designed, some technical measures are used to resolve a series of physical, mathematical and computational problems arising from water-bearing; and so on. The various problems (in such aspects as the designs of physical and calculating schemes and the composition of computational programme) which are exposed in feasibility test, in sensibility test, and especially in operational forecasting experiments are successfully resolved using a lot of technical measures having been developed from researches and tests. Finally, the operational forecasting running of the water-bearing numerical model and its forecasting system is realized stably and reliably, and the fine forecasts are obtained. All of these mentioned above will be described in second paper.

A New Method to Calculate Water Film Stiffness and Damping for Water Lubricated Bearing with Multiple Axial Grooves

Water lubricated guide bearings for hydro turbines and pumps are conventionally designed with multiple axial grooves to provide effectively cooling and flushing away abrasives.Due to the variety of groove configuration in terms of number and size,a predication of their performance is difficult.This paper deals with an analytical procedure to investigate groove effect on load capacity,stiffness and damping for this type of bearing where it is considered as an assembly of many inclined slide bearings.The result can be applied to bearings made of hard materials combined with low bearing pressure.

Nonlinear Vibration Induced by the Water-film Whirl and Whip in a Sliding Bearing Rotor System

Many industrial applications and experiments have shown that sliding bearings often experience fluid film whip due to nonlinear fluid film forces which can cause rotor-stator rub-impact failures. The oil-film whips have attracted many studies while the water-film whips in the water lubricated sliding bearing have been little researched with the mechanism still an open problem. The dynamic fluid film forces in a water sliding bearing are investigated numerically with rotational, whirling and squeezing motions of the journal using a nonlinear model to identify the relationships between the three motions. Rotor speed-up and slow-down experiments are then conducted with the rotor system supported by a water lubricated sliding bearing to induce the water-film whirl/whip and verify the relationship. The experimental results show that the vibrations of the journal alternated between increasing and decreasing rather than continuously increasing as the rotational speed increased to twice the first critical speed, which can be explained well by the nonlinear model. The radial growth rate of the whirl motion greatly affects the whirl frequency of the journal and is responsible for the frequency lock in the water-film whip. Further analysis shows that increasing the lubricating water flow rate changes the water-film whirl/whip characteristics, reduces the first critical speed, advances the time when significant water-film whirling motion occurs, and also increases the vibration amplitude at the bearing center which may lead to the rotor-stator rub-impact. The study gives the insight into the water-film whirl and whip in the water lubricated sliding bearing.

Resistivity tomography study on samples with water-bearing structure

The apparent resistivity of the samples with water-bearing configuration was measured by an electrode-array and 2-D resistivity images of these samples were reconstructed then. The obtained series of tomograms reveal the dis tribution and its variation of true resistivity within the samples caused by the changes of crack and liquid distribu tion. Applying this method to the simulation experiment on the electrical properties of rocks, the fracturing and water filling process, which produces the electrical changes, can be brought to light clearly.

Sedimentary facies and depositional model of shallow water delta dominated by fluvial for Chang 8 oil-bearing group of Yanchang Formation in southwestern Ordos Basin,China

A systematic analysis of southwestern Ordos Basin's sedimentary characteristics,internal architectural element association styles and depositional model was illustrated through core statistics,well logging data and outcrop observations in Chang 8 oil-bearing group.This analysis indicates that shallow water delta sediments dominated by a fluvial system is the primary sedimentary system of the Chang 8 oil-bearing group of the Yanchang Formation in southwestern Ordos Basin.Four microfacies with fine grain sizes are identified: distributary channels,sheet sandstone,mouth bar and interdistributary fines.According to the sandbody's spatial distribution and internal architecture,two types of sandbody architectural element associations are identified: amalgamated distributary channels and thin-layer lobate sandstone.In this sedimentary system,net-like distributary channels at the delta with a narrow ribbon shape compose the skeleton of the sandbody that extends further into the delta front and shades into contiguous lobate distribution sheet sandstone in the distal delta front.The mouth bar is largely absent in this system.By analyzing the palaeogeomorphology,the palaeostructure background,sedimentary characteristics,sedimentary facies types and spatial distribution of sedimentary facies during the Chang 8 period,a distinctive depositional model of the Chang 8 shallow water fluvial-dominated delta was established,which primarily consists of straight multi-phase amalgamated distributary channels in the delta plain,net-like distributary channels frequently diverting and converging in the proximal delta front,sheet sandstones with dispersing contiguous lobate shapes in the distal delta front,and prodelta or shallow lake mudstones.

High Water Content Material Based on Ba-Bearing Sulphoaluminate Cement

A new type of high water content material which is made up of two pastes is prepared, one is refute from lime and gypsum, and another is based on Ba-bearing sulphoaluminate cement. It has excellent properties such as slow single paste solidifing ,fust double pustes solidifing ,fast coagulating and hardening, high early strength, good suspeasion property at high W/C ratio and low cost. Meanwhile, the properties and hydration mechanism of the material were analyzed by using XRD, DTA- TG and SEM. The hydrated products of new type of high water content material are Ba-bearing ettringite, BaSO4 , aluminum gel and C-S-H gel.

Steady Characteristics of the Water-Lubricated Conical Bearings

The water-lubricated conical bearing has attracted attentions of researchers for its simple structure, easily adjusted gap （fdm thickness ）, lower friction loss, and less pollution in application. A mathematic model with consideration of the effects of turbulence, two-phase flow, and temperature on the pressure field at bearing surface is proposed here. Using this model, the Reynolds＇ equation and energy equation are solved in which the thermo- physical properties of the water as lubricant are taken into account. The dependency of characteristics of bearing, such as load-earrying capacity, flow rate （pumping losses ）, and frictional losses, on angular velocity, conical angle, and radial eccentricities, is presented. The research results are beneficial to the improvement of the efficiency of conical bearing and the environmental protection.

纤维材质对UHMWPE水润滑轴承复合材料摩擦学性能的影响

超高分子量聚乙烯(Ultra-high molecular weight polyethylene, UHMWPE)在水润滑轴承领域具有巨大的发展潜力,然而单一的UHMWPE难以满足水润滑轴承的耐磨性需求,尤其是在低速重载工况下.通过纤维改性的方法可以提高其摩擦学性能,但是纤维材质的不同特性对于复合材料摩擦学性能的影响存在差异.通过热压模具分别制备剑麻纤维(Sisal fiber,SF)、碳纤维(Carbon fiber,CF)和聚酯纤维(Polyester fiber,PETF)与UHMWPE混合的定向纤维复合材料,并与纯UHMWPE做对照试验.利用R-tec往复摩擦试验机模拟不同载荷(5和10 N)和不同速度(20、40和60 mm/s)下铜球与不同复合材料的摩擦过程,通过邵氏硬度和极限抗弯强度试验对复合材料力学性能进行表征测试,采用接触角测试复合材料的浸润性,试验结束后用扫描电子显微镜观察表面磨损形貌.结果表明:纤维的力学性能,尤其是硬度和抗弯强度是影响定向纤维复合材料摩擦学性能的关键因素,所添加纤维在复合材料中强有力的支撑作用使摩擦学性能显著提高,纤维的耐磨性和浸润性是次要因素.试验工况下,CF/UHMWPE摩擦系数最低,且在低速重载(载荷10 N,速度20 mm/s)时的摩擦系数与纯UHMWPE相比降低了36.92%;添加耐磨性强的PETF纤维后,复合材料磨损体积与纯UHMWPE相比降低了30.56%.

嵌入式水润滑轴承水膜压力无线传感监测方法

现有测试水润滑轴承特性重要表征参数水膜压力的诸多方法中,由于传感器距离真实测点较远或对轴系创伤较大等原因,导致准确的水膜压力实证数据难以获取,制约了轴承进一步研究与发展。针对上述难题,提出将薄膜传感器嵌入到轴承轴瓦中,而压力数据通过无线传感传输的全新监测方法。首先,建立轴瓦开槽轴承的物理模型,通过对沟槽附近轴瓦变形的有限元分析确定开槽位置、结构与数量;建立轴承流体域和固体域物理模型,对水膜压力分布进行仿真分析;然后,提出薄膜传感器标定方法对其准确标定;最后,进行多工况轴承水膜压力测试试验并与仿真结果和现有方法进行对比分析。研究结果表明,通过在轴承轴瓦开槽嵌入薄膜传感器并进行数据无线传输的方法可行,水膜压力实测数据与仿真结果偏差低于10%,比现有方法实测数据更精确。水膜压力沿轴向递减,轴承内部存在部分润滑膜,处于混合润滑状态。

水润滑轴承衬套装配间隙对轴系振动的影响

水润滑尾轴承通常安装在美人架和尾轴管中,轴承衬套的安装间隙大小直接影响到轴承刚度,从而对轴系振动产生影响,极大程度影响到舰船隐身性能。通过试验验证过盈配合和间隙配合2种安装结构的轴承在静载条件下的摩擦特性与振动特性。结果表明,2种安装间隙下的水润滑轴承的摩擦扭矩的变化趋势一致,均随载荷的增大而增大,随转速的升高而减小,间隙配合轴承的扭矩大于相同工况条件下过盈配合轴承的扭矩;在振动性能上,间隙配合轴承的振动幅值大于过盈配合的轴承,且相比于过盈配合轴承有更大机率出现高频特征频率。在相同工况条件下,过盈配合的轴承的摩擦特性和振动特性均优于间隙配合的轴承。

海上风电单柱复合筒型基础承载特性

文章针对一种新型海上风机基础型式的单柱复合筒型基础的承载特性,在砂土中进行了小比尺物理模型试验。试验中采用了位移控制的水平单调加载方式,选择加载速度与压载为变量,得到水平承载力荷载位移曲线。试验结果表明,基础极限承载力与加载速度和压载质量均呈正相关。得出了基础在加载过程中不同舱内孔隙水压力的变化规律。

矩形沟槽结构参数对水润滑轴承润滑性能的影响

为了研究矩形沟槽结构参数对水润滑轴承弹流润滑性能的影响,建立水润滑轴承流固耦合(FSI)分析模型,采用有限元法,通过比对轴承周向水膜压力、最大水膜压力、摩擦系数、承载力、偏位角和轴承最大径向变形等参数,阐述了矩形沟槽结构参数对轴承润滑性能的变化规律。结果表明,沟槽宽度或深度越大的轴承,其承载性能越差。通过合理调整沟槽的宽深比,可以有效地改善轴承的润滑状态。在相同流水槽总断面积下,沟槽宽深比过大或过小均不是轴承弹流润滑的最好状态,沟槽宽度对轴承承载性能的影响要高于沟槽深度对轴承的影响。

考虑精确磁通的电磁加载装置等效磁路建模

为提高电磁加载装置在控制应用时的模型预测快速性与精确性,考虑电磁加载装置硅钢片表面涡流磁场生成因素与不同轴偏心下有效气隙长度,采用非线性方程拟合硅钢片磁化曲线,建立包含磁极边缘效应、磁极铁心、转子硅钢片动态磁阻与涡流磁场的电磁加载装置非线性等效磁路模型。研究了硅钢片表面涡流磁场生成因素与气隙磁场分布,并与有限元仿真结果比较分析。应用该模型在水润滑轴承试验台上进行电磁加载力测试试验。研究结果表明:等效磁路法对磁场分布的表征与有限元法一致,且对气隙的计算更为精确;电磁加载力稳态误差小于4%,响应时间低于0.55 s。

船舶轮缘推进器关键技术研究现状和发展趋势

采用电力直驱模式来完成电能与机械能的无传动转化是高端交通动力装备领域的未来战略性技术之一。轮缘推进器(RDT)作为一种高度集成的电力直驱推进,是近年来研究的热点。文章梳理了船舶轮缘推进器的6项关键技术,包括水力部件设计及优化、电机设计及控制、水润滑轴承的设计和性能强化、系统集成与测试、船体匹配及联合控制以及可靠性评估与智能运维;阐述了各项技术的研究现状和趋势,总结了国内外RDT产品和实船应用情况。研究和应用表明,节能、环保、灵活的轮缘推进器是绿色智能船舶电力推进形式的重要选择,高性能轮缘推进器专用化设计、效能提升和状态监测以及智能运维是轮缘推进器未来重要发展趋势。

Hydrogeochemical Studies in Drought Scenarios: Canelones, Uruguay Case Study

The water scarcity in quality and quantity is becoming more noticeable and an urgent concern around the world. In Uruguay, these issues become exacerbated by the need to obtain drinking water in coastal areas, influenced by the climate change. Basic and structural geologies are strong conditioners in heterogeneous coastal aquifers. The objective of this study is to characterize the hydrochemistry of the fractured aquifers after having identified the main bearing fractures and the causes of aleatoreous water scarcity and quality problems, for hydric resources sustainable management. Identification of water bearing fracture, hydrogeochemical analysis and water quality evaluation are specific objectives. Some strategies were performed: 1) a base map in QGIS Software;2) fracture photointerpretation;3) geological correlation;4) statistical analysis of the background geochemistry data;5) ions analysis of strategically located wells. There were found water bearing fractures corresponding to 28 m3/h maximum flow rate for the NW-SE and 12 m3/h maximum flow rate for the NE-SW fracture direction, respectively. Besides, there could be a problem related to the high Sodium (Na) and Chloride (Cl) levels. In this respect, having previous data from 25 well samples, ions geochemical analysis has been carried out for 14 wells from Costa Azul and surrounding to have a first approach about the possible cause for the high values of Na (max. 385 mg/L) and Cl (max. 381 mg/L). The selected area for this study has a particular characteristic, because it corresponds to a heterogeneous fractured aquifer, which makes it difficult to catch water with enough flow rates and water quality to meet the population demand.

沱江流域水资源生态安全状况分析

为研究沱江流域水资源可持续利用状况,采用水生态足迹模型计算流域2010—2021年的水资源生态足迹和水资源生态承载力。通过二者的差值水资源生态盈亏指数,对沱江流域内各市近12年的水资源可持续发展状况分析;通过水资源生态压力指数,对沱江流域各市水资源受压迫程度分析。分析结果如下:①沱江流域内水资源生态状况日益改善,至2021年流域内各市水资源生态均处于盈余状态,水资源压力指数均>1,表明流域内各市水资源处于安全状态;②流域内农业水资源生态足迹是总水资源生态足迹主要贡献者;③流域内各市水资源安全状况各异,其中内江市水资源生态压力最大,泸州市水资源丰富有更多合理开发利用的空间。

基于极限平衡理论的陷落柱防水煤柱留设研究

为有效治理含水陷落柱的导水致灾现象,以平朔井工一矿4108工作面为背景,根据井下实际地质生产条件计算防水煤柱极限平衡宽度,从理论层面初步确定防水煤柱留设宽度,同时利用UDEC软件对不同宽度的煤柱塑性破坏进行数值模拟分析。模拟结果表明:当煤柱宽度达到40 m时,煤柱内的屈服区和周边裂隙带基本保持稳定,根据煤柱稳定性对弹性区宽度应大于14 m的要求,防水煤柱宽度应留设40 m;在煤柱宽度与弹性区宽度关系上,煤柱内弹性区的宽度随着煤柱宽度的增加而增加,当煤柱宽度大于40 m时,煤柱内屈服区与塑性区的宽度已基本稳定。4108工作面采用设计的绕过陷落柱方案,优化了绕过陷落柱工序,有效降低了煤炭资源的损失。