Measurement of oil volume fraction and velocity distributions in vertical oil-in-water flows using ERT and a local probe

This paper presents the use of a high performance dual-plane electrical resistance tomography (ERT) system and a local dual-sensor conductance probe to measure the vertical upward oil-in-water pipe flows in which the mean oil volume fraction is up to 23.1%. A sensitivity coefficient back-projection (SBP) algorithm was adopted to reconstruct the flow distributions and a cross correlation method was applied to obtain the oil velocity distributions. The oil volume fraction and velocity distributions obtained from both measurement techniques were compared and good agreement was found, which indicates that the ERT tech- nique can be used to measure the low fraction oil-water flows. Finally, the factors affecting measurement precision were discussed.

Partial dehydration of brucite and its implications for water distribution in the subducting oceanic slab

Hydrous minerals within the subducting oceanic slab are important hosts for water.Clarification of the stability field of hydrous minerals helps to understand transport and distribution of water from the surface to the Earth’s interior.We investigated the stability of brucite,a prototype of hydrous minerals,by means of electrical conductivity measurements in both open and closed systems at 3 GPa and temperatures up to 1300 K.Dramatic increase of conductivity in association with characteristic impedance spectra suggests that partial dehydration of single-crystal brucite in the open system with a low water fugacity occurs at 950 K,which is about 300 K lower than those previously defined by phase equilibrium experiments in the closed system.By contrast,brucite completely dehydrates at 1300 K in the closed system,consistent with previous studies.Partial dehydration may generate a highly defective structure but does not lead to the breakdown of brucite to periclase and water immediately.Water activity plays a key role in the stability of hydrous minerals.Low water activity(a H_(2)O)caused by the high wetting behavior of the subducted oceanic slab at the transition zone depth may cause the partial dehydration of the dense hydrous magnesium silicates(DHMSs),which significantly reduces the temperature stability of DHMS(this mechanism has been confirmed by previous study on super hydrous phase B).As a result,the transition zone may serve as a‘dead zone’for DHMSs,and most water will be stored in wadsleyite and ringwoodite in the transition zone.

Water, Air Emissions, and Cost Impacts of Air-Cooled Microturbines for Combined Cooling, Heating, and Power Systems： A Case Study in the Atlanta Region

城市化进程的加快意味着城市和国际组织需要去寻找各种能够提高能源效率和减少空气中污染物排放的方法。冷热电联产(CCHP)系统可以同时供暖、制冷和发电,具有提高城市或城市区域能源发电效率的潜力。本研究的目的是在满足建筑热需求(供热和制冷)的各种运行条件下,对亚特兰大大都市区内的五种常见建筑类型在采用CCHP系统时的发电耗水、CO_2和NO_x排放,及其经济性进行评价。对于大多数采用或不采用净计量策略的建筑类型来说,以满足每小时热需求去运行CCHP系统均可减少CO_2的排放量。该系统能否对这些建筑类型产生经济效益,主要取决于天然气的价格、净计量策略的采用和假定的CCHP系统的成本结构。当建筑物采用净计量策略并且CCHP系统是以满足建筑物每年的最大热需求而运行时,CCHP系统的发电耗水量和NO_x的排放量均有最大限度的减少,尽管此时该运行情景会增加温室气体排放和发电成本。CCHP系统对中型办公楼、大型办公楼和多户型住宅建筑更经济、实用。

PRIMARY ANALYSIS ON GROUNDWATER,SOIL MOISTURE AND SALINITY IN FUKANG OASIS OF SOUTHERN JUNGGAR BASIN

Soil salinity is the most important factor affecting vegetation distribution,and the secondary salinization has affected the development of oasis agriculture.In arid areas the spatial variation of soil moisture and sa lt content is marked-ly affected by groundwater,irratio nal irrigation in artificial oasis.By analyzing the soil moisture,salt content and groundwa-ter table in different areas of old oasis,new oasis and desert in Fukang Oa sis,it is shown that topography and l and use are main factors affecting the change of groundwater table,the redistribution of soil moisture and salt cont ent.When undis-turbed by human,the groundwater tab le rises from mountain to belt of grou nd water spillage,the groundwater t able rises mightily in plain because of the artificial irrigation,and the secondary salinization of soil is very seriou s.In oasis the ground-water table raises compared with that in the natural desert at the same latitude.In old oasis of upper reaches o f river salt has not been concentrated too much in rhizosphere because this area is the belt of groundwater drainage,soil t exture is coarse,the groundwater table is very low,and the salt in soil is drained i nto the groundwater.The new oasis has been the areas of salt accumulation becau se of the artificial irrigation,the salt content in soil is higher than th at in old oasis,so some cultivated fields here had to be thrown out because of the serious s econdary salinization.

Pressure Distribution Induced by Ionic Wind in Needle-to-water Corona Discharge

The negative DC corona discharge in air at atmospheric pressure was investigated in a needle-to-water system to obtain the pressure distribution of corona ionic wind.The deformation of water surface was measured and the distribution of wind pressure over the water surface was calculated.The effects of varying discharge parameters,such as applied voltage,gap spacing,tip radius of needle,and the shape of grounded electrode,on the wind pressure were studied.The measured wind pressure ranges from several Pa to several tens of Pa and up to 33 Pa over a small area;the pressure is comparatively large in the center and decreases quickly outwards.In the experiment system,a higher voltage on a 3 mm gap resulted in a stronger pressure of the ionic wind;around the onset voltage,using a needle with tip radius of 50μm obtained a larger wind pressure than using a needle with 100μm tip radius,but the latter one can produce larger pressure at higher voltages.Plus,the shape of the grounded electrode only influences the wind pressure a little.

Energy Consumption in the Municipal Water Supply Sector in the Kingdom of Bahrain

Water-energy nexus is an emerging issue that receives considerable attention in the world in general and in the Gulf Cooperation Council (GCC) countries in particular. The GCC countries depend mainly on energy generated from fossil fuels to produce drinking water. Yet, the amount of water-related energy use in Bahrain remains unexplored. This study aims to quantify the amount of energy used in the water supply cycle for the first time in Bahrain using quantitative methods. A bottom-up approach for data collection was adopted where data for the three main stages of the water supply in Bahrain: water production, water transmission, and water distribution were collected. Results show that the water production stage consumes about 97% of the total energy consumption in the water supply sector, followed by water transmission (2.9%) and water distribution (0.1%). Comparisons conducted with best practices in the world show that water desalination plants in Bahrain consume relatively high amounts of energy to produce water based on the desalination technology used. This study calls for focusing on the production stage in achieving energy efficiency since it is the largest consumer and where losses are occurring based on the benchmarking. This study also recommends investigating the share of electricity and thermal energy consumed in the water supply cycle in Bahrain in addition to the wastewater treatment sector. This is imperative to provide a holistic overview of the water-related energy use in Bahrain.

Optimization of the Open Degree of Key Valves Based on Relative Entropy and Pipeline Leakage

Based on information entropy theory, the definition of relative entropy, and the relative entropy minimum principle, this study establishes a multi-objective optimization model for a key valve opening of an urban water distribution network(WDN). Each node pressure is taken as the main research object to reduce pipeline leakage. Moreover, genetic algorithm is applied in the proposed model to solve the key valve opening of the actual WDN in a city in southern China. Using the proposed model, the relevant decision variables of a WDN can be optimized to provide a new manner of network dispatching.

咸淡水组合灌溉对土壤盐分和棉花生长的影响

为揭示不同微咸水(农田排水)与淡水在“先咸后淡”的组合灌溉模式下对土壤容重、盐分迁移和棉花生长的影响。以淡水灌溉为对照(CK),设置7种不同微咸水、淡水组合灌溉(微咸水∶淡水=1∶14(T1)、2∶13(T2)、3∶12(T3)、6∶9(T4)、9∶6(T5)、12∶3(T6)),T7处理采用全额微咸水灌溉,于2022年4-9月进行了棉花田间试验。结果表明,采用微咸水灌溉造成土壤表层盐分积累,0~40 cm土层出现积盐现象,棉花生育期结束后,各处理与淡水对照(CK)比较,T1~T6在0~40 cm土层的电导率分别增加1.16%~26.61%,T7处理电导率增加86.40%;与淡水对照相比,组合灌溉后各处理土层0~40 cm土壤容重明显增加,土壤孔隙度降低,以全额微咸水灌溉T7处理最为显著(容重增加10.24%);微咸水组合灌溉有效提高棉花株高、叶面积指数、茎粗。合理利用微咸水组合灌溉能够为棉花生长提供良好的水盐环境,提高棉花产量,能够为极端干旱区合理利用微咸水提供一种新的灌水模式,为灌区发展节水灌溉及农业可持续发展提供理论支撑。

FIRD-HPD方式对蓝莓干燥特性及品质的影响

为探究蓝莓在FIRD-HPD干燥方式下,内部水分含量及迁移状况随贮藏时间的变化规律,采用低场核磁共振(LF-NMR)及其成像技术(MRI),采集不同水分转换点干燥过程的蓝莓弛豫特性以及质子密度图像信息,分析其规律变化,并研究干燥前、后蓝莓品质的变化。结果表明:在水分转换点为30%,40%,50%时,蓝莓到达干燥终点的时间分别为480,420min和360 min。蓝莓的T2反演谱有3个不同的弛豫峰:T21(0.01~10 ms)结合水、T22(10~100 ms)不易流动水和T23(100~1000 ms)自由水。自由水(T23)和不易流动水(T22)向弛豫时间短的方向迁移,在干燥后期,结合水成为蓝莓中主要水分状态,自由水完全消失。基于MRI技术得到不同干燥方式各干燥阶段的磁共振成像,质子信号随干燥进程逐渐减小。LF-NMR和MRI技术可很好地监测干燥过程中动态水分分布和迁移变化。另外,在40%水分转换点联合远红外热泵干燥处理下,蓝莓果干色泽、营养品质等指标均优于30%和50%的水分转换点联合远红外热泵干燥方式。综合考量后,联合红外干燥水分转换点设置为40%是加工蓝莓果干的最优选择。

基于油藏化学驱能耗分配原理的理想流度控制型驱油剂研究Ⅰ:聚/表二元复合驱油体系的渗流阻力调控机理及应用

针对驱油剂的深部流度控制能力与近井地带注入性之间的矛盾,提出了理想流度控制型驱油剂应满足低黏度配制/输送、近井地带低吸附量长期稳定注入和低浓度产出液的技术要求,同时,在渗流过程中能够在储层深部不同位置建立多级渗流阻力峰值,并且前缘后驱替相渗流阻力应始终保持在较低水平。基于固/液界面吸附作用与分子间相互作用的协同效应,设计了在渗流过程中具备动态改变体系组成和微观溶液结构,从而改变其渗流阻力特征的疏水缔合聚合物/阴离子型表面活性剂二元体系。相较于HP-1(1500 mg/L),表观黏度相近、组成不同的二元体系HP-1(1500 mg/L)/SDSB(150 mg/L)和HP-1(1500 mg/L)/SDSB(200 mg/L),在段塞注入及其后续水驱过程中可以在多孔介质的中、后部构建数值更高、空间分布更优的动态渗流阻力,说明二元体系具备运移增黏特征和延迟突破特征,其前缘的流度控制能力更强,并且渗流阻力在储层的空间分布更合理,从而延长了段塞整体突破时间,有利于提高波及体积和驱油效率。在相对稠油、强非均质性和水驱含水率为80%的渤海某油田油藏条件下,采用基本相同剂量、相近成本的化学剂工业产品进行的驱油实验表明:二元体系后续水驱突破之前驱油剂段塞渗流阻力的空间动态分布特征是影响驱油效率的关键因素,二元体系(AP-P4(1400 mg/L)/ZX-27(300 mg/L),黏度为6.4 mPa·s)比疏水缔合聚合物AP-P4(1750 mg/L,黏度为62.9 mPa·s)多提高10%的原油采收率。

水下多针电极微秒脉冲流光放电特性

多针电极结构是实现大体积水下放电的基础性电极结构,研究其放电基本特性对其他大体积水下放电电极结构的设计具有重要参考意义.本文构建了一个可安装21根针的多针电极,利用四分幅超高速相机研究了单个脉冲放电过程中可能放电的针电极数目以及电极阵列边缘和内侧针电极放电形态的差异;采用COMSOL软件模拟计算了多针电极结构的电场分布,讨论了电场分布对多针电极放电的影响,研究了多针电极结构的放电能量效率.结果发现:在单个脉冲放电过程中,21根针电极不是同时发生放电的,最大放电针电极数目随电压和针针间距的增大而增加.在同一个脉冲放电过程中,位于电极阵列边缘的针电极相比于位于阵列内侧的针电极产生的流光丝较长且偏离针电极轴线的偏角相对较大,这主要是针电极之间电场相互叠加干扰引起的.针针间距越小,针电极之间电场的相互叠加干扰越大,阵列边缘与内侧电极放电形态的差异越大,放电能量效率越低.

Molecular ecological networks reveal the spatial-temporal variation of microbial communities in drinking water distribution systems

Microbial activity and regrowth in drinking water distribution systems is a major concern for water service companies.However,previous studies have focused on the microbial composition and diversity of the drinkingwater distribution systems(DWDSs),with little discussion on microbial molecular ecological networks(MENs)in different water supply networks.MEN analysis explores the potentialmicrobial interaction and the impact of environmental stress,to explain the characteristics of microbial community structures.In this study,the random matrix theory-based network analysis was employed to investigate the impact of seasonal variation including water source switching on the networks of three DWDSs that used different disinfection methods.The results showed that microbial interaction varied slightly with the seasons but was significantly influenced by different DWDSs.Proteobacteria,identified as key species,play an important role in the network.Combined UV-chlorine disinfection can effectively reduce the size and complexity of the network compared to chlorine disinfection alone,ignoring seasonal variations,which may affect microbial activity or control microbial regrowth in DWDSs.This study provides new insights for analyzing the dynamics of microbial interactions in DWDSs.

煤矿典型导含水体井下孔中电法三维正演模拟研究

煤矿开采深度逐步加大,隐伏导含水体成为水害的主要隐患。为了提高孔中电法探测精度,采用有限元法通过电位分析对典型导含水体模型进行全空间三维正演模拟,研究了三维正演理论中的电位计算式、边界问题、变分问题及网格剖分,建立了基础模型,分析了电位分布规律及其误差;针对隐伏正断层、垂直陷落柱、含水采空区典型模型的三维正演模拟结果,总结了各模型的电位等值线特征及变化规律。结果表明,低电阻率使电位等值线变得稀疏,高电阻率使电位等值线变得稠密,且畸变的范围与模型设定的规格相吻合。煤矿井下孔中电法可以有效探测导含水体,探测效率高,靠近靶点,三维正演模拟效果良好,为反演计算提高探测精度奠定了理论基础。

基于组合权重-TOPSIS模型的贵州省水资源承载力评价

以贵州省为研究对象,基于2010—2020年水资源公报、统计年鉴数据等相关数据,从水资源、社会、经济、生态环境4个方面选取16项指标,构建水资源承载力评价指标体系,采用组合权重-TOPSIS模型对研究区88个县进行水资源承载力评价分析。结果表明:1)贵州省2020年县域水资源承载变化范围为0.329~0.716,总体水资源承载状况差异显著,较2010年水资源承载力有明显提升,且2020年水资源承载力呈现黔中区域的水资源承载力较低、周边区域较高的变化趋势,黔东区域水资源承载力最高。2)利用ArcGIS对贵州省县域的水资源承载指数进行全局莫兰指数分析,贵州省县域水资源承载力的莫兰指数为0.515,z值显著大于临界值2.58,p值小于显著性水平,贵州省水资源承载指数呈现空间集聚趋势。3)通过地理探测器分析可知,单因子对水资源承载力影响解释力最大的是人均水资源占有量;双因子交互作用下对水资源承载力的影响程度结果显示,人均水资源占有量是水资源承载力的主导因子。

水冷式盘式组合刹车送钻应用系统

介绍一种新型的水冷式盘式组合刹车送钻应用系统的技术性能、工作原理、结构和特点。该系统由软件和硬件2大部分构成,以水冷式盘式组合刹车的大小气缸为控制对象,采用电控气的原理送钻,形成由钻压外环与气缸压力内环构成的双闭环控制,主控钻压、辅控速度,实现了恒压送钻,保护了设备的安全。将该系统与同类送钻系统进行比较,总结该系统存在的优点和不足,并提出水冷式盘式组合刹车通过钻压优化改进送钻应用系统的方案。

结合谷电制冰的吊顶辐射板室内供冷实例研究

水基吊顶辐射板供冷系统可以提供一个无强烈冷空气对流和噪声的舒适热环境。建立水基吊顶辐射板末端供冷系统模型,结合辐射末端供冷与谷电制冰,通过循环水系统将冰块中储存的冷量输送至辐射板,测量室内垂直方向上的温度分布,分析谷电制冰的吊顶辐射板室内供冷功能。在大连市某厂区办公室进行实例应用,对该方式的应用效果和热经济性进行研究。研究表明,水基吊顶辐射板末端供冷系统可以有效降低室内温度,满足人员热舒适度要求,使用谷电供能制得的冰块作为冷源,辐射板的运行成本可以减少60%。

Combination of drainage, water supply and environmental protection as well as rational distribution of water resource in Zhengzhou mining district

The geological condition of coalfield is much complex in China. With increasing in mining depth and drainage amount, the contradiction of drainage, water supply and environ-mental protection is becoming more and more serious. However, the contradiction can be solved by the scientific management of optimizing combination of drainage, water supply and environ-mental protection. The Philip multiple objectives simplex method used in this article has searched for a possible solution at the first step, and then it goes on searching to find out whether there is a weight number that can lead the solution to the biggest. It can reduce the randomness and diffi-culty of traditional weight method which determine the weight number artificially. Some beneficial coefficients are vague and the number is larger in the model of water resource dispatch. So the vague layer analysis method can consider these vague factors fully, combining the qualitative and quantitative analysis together. Especially, this method can quantify the experiential judge-ment of policy decider, and it will turn to be more suitable if the structure of objective factors is complex or the necessary data are absent. In the paper, the two methods above are used to solve the plans of drainage, water supply and optimizing distribution of water resource in the Zhengzhou mining district.

Combining Market-Based Control with Distribution Grid Constraints when Coordinating Electric Vehicle Charging

The charging of electric vehicles(EVs) impacts the distribution grid, and its cost depends on the price of electricity when charging. An aggregator that is responsible for a large fleet of EVs can use a market-based control algorithm to coordinate the charging of these vehicles, in order to minimize the costs. In such an optimization, the operational parameters of the distribution grid, to which the EVs are connected, are not considered. This can lead to violations of the technical constraints of the grid(e.g., undervoltage, phase unbalances); for example, because many vehicles start charging simultaneously when the price is low. An optimization that simultaneously takes the economic and technical aspects into account is complex, because it has to combine time-driven control at the market level with eventdriven control at the operational level. Diff erent case studies investigate under which circumstances the market-based control, which coordinates EV charging, conflicts with the operational constraints of the distribution grid. Especially in weak grids, phase unbalance and voltage issues arise with a high share of EVs. A low-level voltage droop controller at the charging point of the EV can be used to avoid many grid constraint violations, by reducing the charge power if the local voltage is too low. While this action implies a deviation from the cost-optimal operating point, it is shown that this has a very limited impact on the business case of an aggregator, and is able to comply with the technical distribution grid constraints, even in weak distribution grids with many EVs.

燃料驱动无电热泵系统的节能模拟与运行经济性分析

创新性提出了一种燃料驱动无电热泵系统(NEHP)的热泵新技术,NEHP使用一套系统解决了夏季供冷、冬季供暖、生活热水及一定量生活用电,是一种可冷热电多联供的分布式能源系统。本文从原理及设计思路上对NEHP新技术进行了具体说明,对NEHP技术应用的节能性进行了模拟计算,并对运行经济性作了全面分析。NEHP技术适宜应用于缺电和无电地区,具有电热泵(EHP)无法比拟的适用性优势,也适用于燃气与电力均较为充裕的地区,具有广阔的应用场景。对于使用燃气的NEHP-G系统,若气电比rge小于某一数值,则在供热或供冷方面NEHP-G将比EHP具有更低的运行费用,其中额定制热时该值为4.17,额定制冷回收与不回收余热时该值分别为5.62和3.06。以重庆地区2021年商业气价与电价为例,NEHP-G在制热季可节省费用42.17%~47.49%,在制冷季回收与不回收余热可分别节省费用48.22%与32.26%。

长壁工作面支架阻力与涌水量时间序列数据联动关系分析

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