Deep Installation Research Articles

A semi-analytical hydrodynamic model for floating offshore wind turbines (FOWT) with application to a FOWT heave plate tuned mass damper

This paper proposes a semi-analytical MacCamy–Fuchs–Morison (MFM) hybrid hydrodynamic model for very efficient simulations of FOWT responses without resorting to potential flow solvers. First, closed-form expressions of the 6-by-6 added mass matrix and 6-dimensional complex wave load transfer function are derived based on the Morison equation. Comparison of the wave load models show that the pure Morison model over predicts high-frequency wave loads above the diffraction limit, while the pure MacCamy–Fuchs model performed poorly at low frequencies due to the existence of heave plates. The MFM hybrid model resolves both issues and gives good agreement with the potential flow theory at all frequencies. The proposed MFM hybrid model is then employed to a representative application case, i.e. a semi-submersible FOWT installed with heave plate tuned mass dampers (HPTMDs). It is shown that implementing a deep installation of the HPTMDs effectively suppresses foundation roll, heave responses and tower side–side vibrations.

Computational fluid dynamic study on design and modification of underwater remotely operated vehicle

Remotely Operated Vehicle (ROV) has been widely used in numerous underwater exploration applications such as exploration of complex deep sea environment, pipeline detection, installation, maintenance, and repair. Thus, it is worthy to design, optimize, and performance evaluation of ROV systems for underwater exploration purposes. Computational Fluid Dynamic (CFD) is a computational approach that is very helpful and widely used to examine the flow characteristics of ROV systems. In this research work, CFD analyses of ROV bodies with different thruster blades were carried out in order to generate thrust forces by the thruster blades. For this purpose, ANSYS FLUENT was used to examine the flow characteristics over the ROV body. The analyses were performed at different flow velocities, such as 1 m/s, 1.5 m/s, 2 m/s, 2.5 m/s, 3 m/s and 3.5 m/s. The outcomes were in the form of thrust force, drag force, pressure distribution, and velocity distribution. The result shows that four-blade thruster generates maximum thrust force as compare to other ROV thruster models. The main reason behind this higher thrust force is due to the larger motion of the fluid. Similarly, drag force was also investigated and observed that the drag force is greater for thruster model 3, having four blades due to the large frontal area of the ROV body and thruster blades. The results obtained in this study are very helpful for engineers and researchers to design and optimize ROV models using numerical methods.

DETERMINATION OF THE MAIN INDICATORS OF HYDROMECHANICS OF TWO-PHASE SYSTEMS BASED ON LABORATORY STUDIES

As far as we know, there is no branch of industry where two-phase systems are not used. This is the chemical, thermal, physical and finally the oil industry. The process of studying two-phase systems is a branch of hydromechanics and reflects great scientific research works in recent times In the work under review, the main characteristics of the water-oil mixture were studied and the main hydromechanical indicators of this system were determined. The results of the conducted researches were applied in deep pump installations. The formation of these mixtures affects the operation of the submersible pump to some extent Keywords: oil, reservoir water, rods, pump working process, valves, pump cylinder.

A potential source of low-manganese, arsenic-safe drinking water from Intermediate Deep Aquifers (IDA), Bangladesh

Elevated manganese (Mn) concentration in many drinking water tubewells in Bangladesh has made access to safe drinking water more critical despite providing arsenic (As) safe water to millions of people after decades of efforts to achieve latter. This study evaluates the potential of the Intermediate Deep Aquifer (IDA) in the Matlab area of Bangladesh as a source of As-safe and low-Mn groundwater. Based on observations from depth-specific piezometer nests, drinking water tubewells were installed at a targeted depth of 120 m in the Matlab region, an As-hot spot in the country. Water chemistry analysis of 243 Intermediate Deep Tubewells (IDTW) provided promising results which support the strategy of exploiting the IDA as a safe source for drinking water tubewells. Arsenic, manganese and other trace elements, along with the major ions, were analyzed by high-precision ICP-OES and ion chromatography. The Bangladesh drinking water standard for As (50 μg/L) was exceeded only in 3 wells (1%) while 99% (n = 240) of the wells were found to be safe. More than 91% (n = 222) were within the WHO guideline value of 10 μg/L. For Mn, 89% (n = 217) of the wells showed the concentration within or below the former WHO guideline value of 0.4 mg/L with a mean and median value of 0.18 and 0.07 mg/L respectively. Similar high permeability sand units at this depth range, if available could be targeted by the local tubewell drillers for tapping water at half the cost of deep tubewell installation, which will be quite encouraging for the local community, considering their affordability for installation of As-safe and low-Mn drinking water tubewells. This study's results could also be important for other relevant stakeholders, including the policy makers, implementing agencies and the water sector development partners, as well as water supply projects elsewhere in the world with similar hydrogeological settings.

Hardening the rolling surface of the wheels bandage after mechanical treatment

Article describes calculated argumentation of the striker sealing surface, in the form of the two cylinders with parallel axes model of loading, having an effect on the rim surface of the wheel pairs of rolling-stock. There has been presented a calculation variant of the depth of hard running surfacing of the rolling-stock wheel pairs. Installation of deep hardening of rolling surfaces of wheel sets allows the special striker to create certain forces on the rolling surface of the wheel rim, to deform the surface layer to a certain depth, thereby increasing the hardness of the deformed surface. The article presents the technology for hardening the wheel running surface by loading the surface of the wheel set bandage, by means of the deep hardening installation with the creation of strain stress in the surface layers for several combinations of tensile strength σB and velocity σT of various bandage materials.

A Generalized Method of Decreasing Data Redundancy

In this paper, a method of decreasing the redundancy of information flow by using recurrent properties of Galois code sequences is proposed. For this purpose, the service information is compiled and the priority compression is identified. The method is based on applying one of the adaptive algorithms (prediction first-order, interpolation zero-order, interpolation first-order) by comparing the efficiency of its use when applied to the selected fragments of a signal. It is shown that the developed method is effective for the quick-change signals when the structure and behavior of a signal change drastically. The efficiency of redundancy decreasing at the different sampling rate and the number of the significant samples is evaluated. This makes it possible to establish the limits of the positive effect for redundancy of information flows for the existing and developed methods. Experimental research is carried out for various permissible deviations with obtaining the number of the significant readings. A comparison of the obtained data with results of applying the existing methods in deep pumping installations proved that the proposed method is in 1.3 times more effective than existing ones.

ANALISIS PRODUKTIVITAS ALAT PANCANG HYDRAULIC STATIC PILE DRIVER UNTUK MENINGKATKAN KINERJA WAKTU PADA PROYEK APARTEMEN APPLE 3 CONDOVILLA

The selection of work methods is very important, especially inthe deep pilling installation methode. Hydraulic Static Pile Driver (HSPD) piling equipment is selected since the method uses static pressure without negative impacts (noise and vibration) for residents around the project during piling process. However, it needs to find out effective and efficient levels, and also productivity of this method. This paper will discuss the productivity and some strategies to improve duration level of pilling equipment for Apple 3 Condovilla apartment project. From analysis, it was found that the productivity value was less than one (<1) for day 2 and 4. Several factors affect the productivity of the piling equipment, such as: late start or early quits on the schedule; equipment damage, worker skills, material production, material mobilization, location of pile material, and the final set of piling. Some strategies can be performed to improve duration, such as: workers coordination workers, periodic equipment maintenance, production, mobilization, and placement of materials.

Design and analysis of deepwater tension sensors for ice drill application

AbstractMonitoring the tension in cables is significant in some ice drill and deepwater applications. Take our RECoverable Autonomous Sonde (RECAS) for example. It is able to melt a hole to the bottom of ice sheet and is able to move upwards. A winch is installed inside RECAS to release and recover the cable, whose tension needs to be monitored in real time in order to control the behavior of the winch. The high pressure of deep water and limited installation space pose great challenges in sensor development. In this paper, two editions of newly designed deepwater tension sensors are proposed. The first edition is based on a fresh hydraulic load module that operates in high pressure environment and the second edition tension, which aims to improve the accuracy, applies a newly designed watertight load module. Detailed force transmission and characteristic analysis of the sensors are carried out. The sensors have got through a series of experiments, including calibration experiments, pressure experiments and field experiments. The resultant accuracy of the second edition sensor, which has a better performance, is over 2% under the measuring range of 1000 kg and the dimension of the final sensor is as compact as 150 mm × 137 mm × 86 mm.

Modeling, simulation, and optimization of geothermal energy production from hot sedimentary aquifers

Geothermal district heating development has been gaining momentum in Europe with numerous deep geothermal installations and projects currently under development. With the increasing density of geothermal wells, questions related to the optimal and sustainable reservoir exploitation become more and more important. A quantitative understanding of the complex thermo-hydraulic interaction between tightly deployed geothermal wells in heterogeneous temperature and permeability fields is key for a maximum sustainable use of geothermal resources. Motivated by the geological settings of the Upper Jurassic aquifer in the Greater Munich region, we develop a computational model based on finite element analysis and gradient-free optimization to simulate groundwater flow and heat transport in hot sedimentary aquifers, and numerically investigate the optimal positioning and spacing of multi-well systems. Based on our numerical simulations, net energy production from deep geothermal reservoirs in sedimentary basins by smart geothermal multi-well arrangements provides significant amounts of energy to meet heat demand in highly urbanized regions. Our results show that taking into account heterogeneous permeability structures and a variable reservoir temperature may drastically affect the results in the optimal configuration. We demonstrate that the proposed numerical framework is able to efficiently handle generic geometrical and geological configurations, and can be thus flexibly used in the context of multi-variable optimization problems. Hence, this numerical framework can be used to assess the extractable geothermal energy from heterogeneous deep geothermal reservoirs by the optimized deployment of smart multi-well systems.

Reliability of bonded anchors with different installation techniques: experimental assessment

Experiments were performed to evaluate the reliability of different mixing and installation conditions of post-installed bonded anchors. Three two-component products (one provided with cartridges and proprietary mixing system and two with components required to be mixed by the user) were tested and their performances were compared. As part of the test program, reference tests (aimed at establishing the baseline performance of the products) and reliability tests (aimed at evaluating the influence on the baseline performance of different mixing techniques, installation directions, deep installation, and reduced cleaning) were performed. Tests and assessment of the performances were carried out following the requirements of available qualification standards. The results show that systems that require to be mixed by the user can lead to unsafe and unreliable fastening solutions and highlight the need for proper definition of product qualification procedures, their link to design codes, scope of application, product information, and installation instructions of these systems.

Open‐loop geothermal heat exchanger system for heating and cooling of the Sport arena in Skopje

AbstractThe alternative energy sources are essential for the sustainable development and protection of the environment. In this context, the renewable energy usage had become the new engineering paradigm. The direct use of geothermal energy for cooling and heating is simple and efficient alterative which is widely available and without any restrictions or conditions. Nowadays, more and more buildings use the geothermal energy satisfying more than 80% of the total energy demand for heating and cooling. Most popular are the geothermal heat exchanger systems with deep installations due to their efficiency and cost‐effectiveness. Such an example is the geothermal system of the new Sport arena build in Skopje with open‐loop geothermal heat exchangers is classified as energy efficient facility under class. The primary fluid‐water is exhilarated from the five 30 m geothermal exploitation wells, which through heat pumps is brought to the accumulation chamber inside the building bellow the main court where the heat is stored. Hence, the system is planned to operate in night mode during the cheaper energy tariff used by energy pumps, later to use the stored heat or cold for daily needs. A significant role in the system plays the controlling system with three different management levels.

Thermal evaluation of coaxial deep borehole heat exchangers

This paper presents a performance study of deep borehole heat exchangers. The coaxial borehole heat exchanger (BHE) has been selected because for the present conditions it has a better performance than the conventional U-tube BHE. A numerical model has been developed to study the coaxial BHE. The model predictions are compared to detailed distributed temperature measurements obtained during a thermal response test. The model is found to accurately predict the behavior of a coaxial BHE. The influence of the flow direction of the mass flow is studied for BHEs in the range 200 m–500 m. A parametric performance study is then carried out for the coaxial case with different borehole depths, flow rates and collector properties. The results clearly show a significant increase in the system performance with depth. In addition, it is shown that with increasing borehole depth, the heat load that can be sustained by the BHE is significantly increased. An overall performance chart for coaxial BHEs for the depths of 300–1000 m is presented. The chart can be used as a guide when sizing deep BHE installations.

Quantitative safety assessment of pressure control failure in a deep underground large scale cryogenic installation

This work considers the safety analysis and quantitative risk assessment of a cryogenic installation located in specially excavated caverns 1400m underground. The installation includes a custom-designed heat insulated Tank hosting over 65kt of cryogenic argon. The conditions inside the Tank and its cavern will be maintained using appropriate process systems for cooling, heating, pressurization and filtration. Smaller adjacent caverns will host the auxiliary process equipment. This paper identifies the possible hazards, quantifies accident occurrence frequencies, and performs detailed simulations of accidental argon release due to pressure control failures. The quantitative results indicate weak spots for improvements on the current process design of the installation.

Modal Reduction Based Tracking Control for Installation of Subsea Equipments

This paper proposes a control strategy for the deep sea installation of wellhead equipments hanged by flow line structures, named risers. A fundamental step of this operation is the positioning of the equipment over the wellhead, which can be costly, time-consuming, and unfeasible in bad weather conditions. The approach taken considers the riser structure an Euler-Bernoulli beam submerged in a fluid, whose top end is fixed in the offshore platform and the bottom end attached to a payload. A dynamic analysis is carried to identify the structure's most significant modes of vibration and create a reduced-order model. Then, a flatness-based approach is used for trajectory planning and tracking, resulting in a low complexity control structure. Numerical simulations are presented to validate the proposed controller and to analyse its performance in the presence of external perturbations.

Identifying best practice, installation, laboratory testing and field testing

This paper summarizes recommendations for best practice associated with the installation of geothermal loops within foundations to form thermopiles, based on experience gained over the past 10 years in the UK. The issue of paramount importance in constructing a successful thermopile installation is the early stage coordination with all parties that will encounter, install or test the geothermal loops. Several lessons learned from the installation and construction of thermopiles are described to help ensure a smooth installation process. As long as there is early coordination, the installation of geothermal heat exchange tubing is relatively simple and will have very little or no impact on typical deep foundation installation procedures. This, coupled with the fact that there are additional costs and implications associated with other geothermal heat exchange approaches, implies that thermopiles are an ideal economic solution to access a renewable energy source.

Application of Mechanical Energy Storage in Micro-Fluid Turbine Design

A micro-fluid turbine with mechanical energy storage system is designed and successfully tested in laboratory. As energy supplement for deep ocean installations, this patent design solved the problem of difficult generating electricity in ultra-low speed flow. The conventional marine current turbine can hardly get start in flows with velocity lower than 0.5m/s, whereas the marine current speed is seldom higher than one knot in deep sea. By adding a mechanical energy storage system, the rotor of the micro-fluid turbine first captures the fluid kinetic energy from the ultra-low speed flow, and then the energy transferred to the mechanical energy storage system, in which a plane scroll spring is used to store the limited energy and drive the generator automatically when it has enough potential energy. Simulation and laboratory test show that this method has potential for power generating in low density ocean current environment.

Measured and Predicted Response of a New Jetted and Grouted Precast Pile with Membranes in Cohesionless Soils

AbstractWith increased urbanization, deep foundation (bridges, signage, walls, etc.) selection is moving toward the minimization of disturbance and installation time, as well as addressing quality control and assurance issues. Unfortunately, many types of deep foundations involve noise and vibration during installation (e.g., driven piles) or integrity and reduced resistance issues (e.g., drilled shafts, both conventional and post grouted tip, continuous flight auger piles). This paper presents a new foundation type, a jetted and grouted precast pile, which uses the advantages of several proven deep foundation installation techniques. The installation of the new pile is comprised of three distinct phases: (1) pressurized water-jetting of a precast pile into the ground; (2) side grouting of the pile; and (3) tip grouting. The pile has two separate side grouting zones, each with its own grout delivery system. Each grout zone is covered with a semirigid membrane, which results in radial expansion of the soil...

Site studies and R&D for a water Čerenkov Megaton detector in Europe

MEMPHYS is a 0.5 Mton scale Water Čerenkov detector proposed for a deep underground installation - possible sites are under study in the European FP7 design study LAGUNA. It is dedicated to nucleon decay, neutrinos from supernovæ, solar and atmospheric neutrinos, as well as neutrinos from a future super-beam or β-beam. Its performance with neutrino beams includes the posibility of measuring the mixing angle θ13, the CP violating phase δ and mass hierarchy. One R&D item currently being carried out is MEMPHYNO, a small-scale prototype with the main purpose of serving as a test bench for new photodetection and data acquisition solutions, such as grouped readout and systems.

Geoelectric resistivity sounding for deciphering hydrogeology and locating deep tubewell installation sites in Puroshava area of Bagerhat, Bangladesh

The study area includes Bagerhat Pouroshava and its surroundings under Bagerhat Sadar Upazila covering an area of 7.53 sq. km with a population of about 50,000. Bagerhat is a coastal district and the subsurface geology is complicated. As in other areas of the coastal belt the quality of ground water in the area is also variable. For ground water development in the study area the shallow aquifer is not suitable as the water is mostly saline to brackish except some isolated fresh water pockets of limited yielding capacity. The deep aquifer is also not very homogeneous in water quality. In the northwestern part it bears fresh water but water quality deteriorates south-southeast with higher depth of occurrence. A comprehensive study is carried out to demarcate the aquifers and to judge the water quality to find the suitable location of the deep tube wells in Bagerhat Pouroshava area.
 Fifteen geoelectric soundings have been executed in the study area using Schlumberger configuration with maximum spreading of 1200 m. Based on the vertical electrical sounding interpretation results the subsurface sequence is divided into following geoelectric units: The top unit has resistivity less than 5.0 Ωm with a thickness of 1.5 to 20 m and represents the top clay­ silty/sandy clay layer. The second geoelectric unit represents a very fine to medium sand with thin clay lenses and resistivity varying from 5.0 Ωm to more than 100.0 Ωm with a thickness of 16 to 135 m. The resistivity of the following unit ranges from l.40 Ωm to 4.8 Ωm and thickness varies from 100 m to more than 300 m. The deepest geoelectric unit shows resistivity from 8.0 Ωm to 18.0 Ωm and represents the deep aquifer. The depth to the aquifer varies from 235 m to 355 m. The most suitable site for groundwater development from the deep aquifer is in the vicinity of East Saira of Shatgambuj union.

KM3NeT: towards a km 3-scale neutrino telescope in the Mediterranean Sea

The observation of high energy neutrinos ( ≳ 1 TeV ) from astrophysical sources would substantially improve our knowledge and understanding of the non-thermal processes in these sources, and would in particular pinpoint the accelerators of cosmic rays. Theoretical predictions indicate that km3-scale detectors are needed to detect astrophysical neutrino fluxes. That is the reason why the three Mediterranean experiments, ANTARES, NEMO and NESTOR are working together on preparing KM3NeT, a large deep-sea neutrino telescope in the Mediterranean Sea which will survey a large part of the Galactic disc, including the Galactic Centre. It will complement the IceCube telescope currently under construction at the South Pole. Furthermore, the improved optical properties of sea water, compared to Antarctic ice, will allow for a better angular resolution and hence a better background rejection. The construction of this detector will require the solution of technological problems common to many deep submarine installations, and will help paving the way for other deep-sea research facilities. In this paper the major activities and the status of KM3NeT are presented.