Impact of Groundwater Flow and Energy Load on Multiple Borehole Heat Exchangers          下载免费PDF全文

S. Emad Dehkordi  Robert A. Schincariol  Bo Olofsson 《Ground water》2015,53(4):558-571

The effect of array configuration, that is, number, layout, and spacing, on the performance of multiple borehole heat exchangers (BHEs) is generally known under the assumption of fully conductive transport. The effect of groundwater flow on BHE performance is also well established, but most commonly for single BHEs. In multiple‐BHE systems the effect of groundwater advection can be more complicated due to the induced thermal interference between the boreholes. To ascertain the influence of groundwater flow and borehole arrangement, this study investigates single‐ and multi‐BHE systems of various configurations. Moreover, the influence of energy load balance is also examined. The results from corresponding cases with and without groundwater flow as well as balanced and unbalanced energy loads are cross‐compared. The groundwater flux value, 10^?7 m/s, is chosen based on the findings of previous studies on groundwater flow interaction with BHEs and thermal response tests. It is observed that multi‐BHE systems with balanced loads are less sensitive to array configuration attributes and groundwater flow, in the long‐term. Conversely, multi‐BHE systems with unbalanced loads are influenced by borehole array configuration as well as groundwater flow; these effects become more pronounced with time, unlike when the load is balanced. Groundwater flow has more influence on stabilizing loop temperatures, compared to array characteristics. Although borehole thermal energy storage (BTES) systems have a balanced energy load function, preliminary investigation on their efficiency shows a negative impact by groundwater which is due to their dependency on high temperature gradients between the boreholes and surroundings.  相似文献   

Effect of texture of carbonate soils in South Iran coasts on aggregate crushing     

Mahmoud Fatemiaghda  Habib Shahnazari  Mehdi Talkhablu 《Marine Georesources & Geotechnology》2017,35(7):986-998

Aggregate crushing is a phenomenon occurring in carbonate soils under shear and compressive loads resulting in settlement of the offshore structures such as piers, bridges, waterfronts, wharfs, and oil and gas extraction platform foundations. Therefore, it is of significant importance to address the above-mentioned issue through a comprehensive study. In the present research, the texture of carbonate soil in south Iran coasts and its effect at high hydrostatic pressure (2?MPa) on aggregate crushing was studied. The physical properties of coastal soils, such as the effective grain size, shape index, and angularity were then characterized to investigate their effect on grain crushing grade. The results showed that the effective grain size, shape index, angularity, and calcium carbonate content are the main parameters affecting the crushing of grains and consequently settlement of marine soils. Based on the above parameters, a relationship is proposed to estimate grain crushing in carbonate soils.  相似文献   

Experimental study on the phase transformation point of crushable and noncrushable soils     

Habib Shahnazari  Mohammad Amin Tutunchian 《Marine Georesources & Geotechnology》2017,35(2):176-185

Two marine calcareous deposits as crushable soils and a siliceous sand as a noncrushable soil were used in this study to compare their monotonic response. Undrained monotonic triaxial tests were conducted on samples, which were prepared in different relative densities and consolidated under various confining pressures. The location of phase transformation point in undrained response of the sands in different initial conditions was evaluated. The effect of important parameters including relative density, confining pressure, particle shape, and particle breakage on phase transformation point was assessed. The input energy applied per unit volume of the soils was used to interpret the shearing response of crushable and noncrushable soils. The results showed that calcareous sands have more tendencies in contraction. Particle shape and breakage play a key role in engineering behavior of crushable soils.  相似文献   

First record of Lepidocybium flavobrunneum (Pisces: Gempylidae) from New Zealand     

C. D. Paulin  G. Habib 《新西兰海洋与淡水研究杂志》2013,47(4):405-407

Lepidocybium flavobrunneum (Smith, 1849) is widespread in warmer oceanic waters and has recently been recorded in the catches of tuna longline vessels in the New Zealand region. Twenty‐five specimens were caught at 31°46′‐32°03′S, 170°49′‐171°11′ E on 23–27 June 1979, thus extending the known range of the species to northern New Zealand.  相似文献   

Viscous, cohesive, non-Newtonian, depositing, radial slurry flow     

Habib Alehossein   《International Journal of Mineral Processing》2009,93(1):11-19

Mining induced subsidence can significantly affect mining costs where major surface facilities and natural environment need to be protected. Overburden grout injection is a technology used to control coal mine subsidence by injecting the mine waste material extracted from the coal back into the inter-burden rock during longwall mining. The flowing slurry is here categorised as a nonlinear viscous cohesive (Bingham plastic) fluid. During longwall mining the grout slurry is pumped into the separated beds of the rock mass through a central vertical borehole, which is drilled deep into the inter-burden rock strata above the coal seam. However, a blockage can occur in the injection system when the slurry velocity falls below a certain critical threshold velocity, indicating a material phase change from cohesive-viscous to cohesive-frictional. In situ field injection tests through boreholes have been simulated at a smaller scale at the CSIRO laboratory in Brisbane by pumping the slurry through a radial disk (gap = 4 mm) from its centre. Laboratory experiments indicate a general, nonlinear, cohesive, viscous, frictional model for shear behaviour of the slurry, in which the material shear parameters are functions of the disk radial distance. Complete dimensional and dimensionless analytical solutions have been developed based on an approach related to Bingham–Herschel–Bulkley fluid mechanics. The derived formulae include relations for minimum pump pressure, local pressure and pressure gradient, wall shear stress, volume rate, velocity and velocity gradient. The theoretical results match the experimental measurements. The experiments covered slurries with maximum particle sizes of 0.5 to 2 mm with about 50% being larger than 100 µm. The viscosities at the various solids concentrations were measured with a standard torsion viscometer. This study differs from the previous research in several distinct aspects, namely, consideration of the variable shear parameters rather than fixed values, inclusion of total nonlinear behaviour, and implementation of a friction function to mimic behaviour of the deposited and consolidating stiff slurry, which can cause a significant pressure rise as a result of the increased shear resistance.  相似文献   

Rejuvenation of dry paleochannels in arid regions in NE Africa: a geological and geomorphological study     

Bahay Issawi  Emad S. Sallam 《Arabian Journal of Geosciences》2017,10(1):14

Although the River Nile Basin receives annually ca. 1600 billion cubic meters of rainfall, yet some countries within the Basin are suffering much from lack of water. The great changes in the physiography of the Nile Basin are well displayed on its many high mountains, mostly basement rocks that are overlain by clastic sediments and capped by volcanics in eastern and western Sudan. The central part of the Nile Basin is nearly flat including volcanics in the Bayuda Mountains and volcanic cones and plateaus in southwestern Egypt. The high mountains bordering the Nile Basin range in elevation from 3300 to 4600 m.a.s.l. in the Ethiopian volcanic plateau in the east to ca. 3070 m.a.s.l. in the western Gebel Marra, and 1310 m.a.s.l. in the Ennedi Mountains in northwestern Sudan. In central Sudan, the Nile Valley rises approximately 200–300 m.a.s.l. In Egypt, the River Nile is bounded by the Red Sea Mountains in the east, assuming ca. 1000–2600 m.a.s.l., mostly of basement rocks, which are covered to the north of Aswan by Phanerozoic sediments sloping to the west, passing by the Nile Valley and continuing through the Western Desert. The Phanerozoic cover on both sides of the Nile is known as the Eastern and Western Limestone Plateaus. These plateaus assume elevations varying from 300 to 350 m.a.s.l. near the eastern bank of the Nile to 400–500 m.a.s.l. south Luxor at Esna and west of Aswan. The nearly flat Sahara west of the Nile Valley rises gradually westward until it reaches Gebel Uweinat in the triple junction between Egypt, Sudan, and Libya. Gebel Uweinat has an elevation of 1900 m.a.s.l. sloping northward towards the Gilf Kebir Plateau, which is 1100 m.a.s.l. The high mountains and plateaus in the southern and western Egypt slope gradually northward where the Qattara Depression is located near the Mediterranean coast. The depression is ?134 m.b.s.l., which is the lowest natural point in Africa. All these physiographic features in Sudan and Egypt are related to (i) the separation of South America from Africa, which started in the Late Paleozoic and continued up to the Cretaceous, giving rise to several generally E–W-oriented tectonic features inside Africa, (ii) the uplift of the Red Sea Mountains and their continuation inside Africa resulted in the East African Rift System (EARS), (iii) the Guinea–Nubia Lineament crossing Africa from the Atlantic to the Red Sea where many havoc trends, mostly E–W-trending faults, and uplifted basement features pierce the overlying sediments, (iv) parallel and longitudinal structures associated with volcanic plateaus and cones extend from west Sudan (Gebel Marra) to Ethiopian Plateau, passing by volcanics and plume features in between and the basins in east Africa were subjected to wrench related inversions, and (v) the Sudd linear E–W area stretching more than 1000 km between Gebel Marra in the west, passing by South Sudan and reaching southwestern Ethiopia. Here, fluviatile and subsurface waters led to ponds, lakes, and wet areas that are hard to exploit. The impact of these features led to the present south to north River Nile, but passing by many changes in the direction of its many tributaries and slope reversal of some of the major extinct rivers, either sectors of the main Nile or the rivers once flowed into the main river. The paleoclimatic changes during the Quaternary period: wet and dry have a great effect on the physiographic features and slope reversal of the Nile Basin drainage system.  相似文献   

Evaluating the impact of management scenarios and land use changes on annual surface runoff and sediment yield using the GeoWEPP: a case study from the Lighvanchai watershed,Iran     

Roya Narimani  Mahdi Erfanian  Habib Nazarnejad  Ahmad Mahmodzadeh 《Environmental Earth Sciences》2017,76(9):353

This study was undertaken to evaluate land use change impact and management scenarios on annual average surface runoff (SR) and sediment yield (SY) using the GeoWEPP tool in the Lighvanchai watershed (located in northwestern Iran). Following a sensitivity analysis, the WEPP model was calibrated (2005–2007) and validated (2008–2010) against monthly observed SY and SR. The coefficient of determination (R ²), Nash–Sutcliffe efficiency (NSE), mean bias error (MBE), and root-mean-square error (RMSE) were applied to quantitatively evaluate the WEPP model. The results indicate a satisfactory model performance with R ² > 0.80 and NSE > 0.60. Therefore, the model for current land use (scenario 1) was run for a 30-year time period (1982–2011). The annual average of SR and sediment load were predicted as 93,584 m³/year and 4340 ton/year, respectively. To reduce the annual average surface runoff and sediment yield at the watershed scale, the second scenario (alfalfa cultivation with suitable tillage) and the third scenario (grassland development) as two management scenarios of land use changes were defined by identifying the critical hillslopes. The rate of SR and sediment load in the second scenario were 42,096 m³/year and 429 ton/year, respectively. For the third scenario, the model predictions were 30,239 m³/year and 226 ton/year, respectively. Compared to the first scenario, the reduction rates in annual average of sediment load were about 90 and 94%, respectively. Moreover, for the second and third management scenarios, the reduction rates in annual average of SR were about 55 and 67%, respectively.  相似文献   

Characteristic of groundwater potentialities in West Nile Valley South,Minia Governorate,Egypt     

Esam Ismail  Esam El-Sayed  Sameh Sakr  Emad Youssef 《Arabian Journal of Geosciences》2017,10(23):521

The main aim of the present study is to detect the status of groundwater resources in west Mallawi area which represented one of the new reclamation lands. In order to achieve this aim, the hydrogeological and hydrogeochemical studies are carried out, based on the results of 21 pumping tests and chemical analysis of 29 water samples. Two water-bearing units are detected in the study area, namely, the Eocene fractured limestone aquifer which occupies the east portion of the studied area. The second aquifer consists of friable sediments of sand and gravel and may be related to the late Oligocene–early Miocene age and overlies the limestone rocks in the west, and this aquifer were studied for the first time in this work. Regionally, the groundwater flow in the area under study occurs toward the north and east directions. There is a hydraulic connection between both aquifers through the structural pattern affected the area. The partial recharge of the both aquifers takes place through the upward leakage from deep aquifers and the Nile water. There is a general decrease in the water salinity from west to east direction. The groundwater of both aquifers was evaluated for the different purposes and concluded that, it is considered suitable for different uses.  相似文献   

The eugeosynclinal filling (Abu Ziran Group) in the area SW of port Safaga,eastern desert     

S. El-Gaby  M. Habib 《Precambrian Research》1978,6(1):A16-A17

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Autonomous space resection using Point- and Line-Based representation of FREE-FORM control Linear Features   总被引：1，自引：0，他引：1  

Ayman Habib  Hsiang Tseng Lin  Michel Morgan 《The Photogrammetric Record》2003,18(103):244-258

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