Hydraulic Laboratory Research Articles

A holistic review on hydraulic fracturing stimulation laboratory experiments and their transition to enhanced geothermal system field research and operations

This paper presents a thorough overview of hydraulic stimulation techniques, conducted in laboratories. It further analyses field experiments and ongoing projects for geothermal energy production to investigate if the findings from the lab can be practically applied to the field. Stimulation techniques have been long used in the oil and gas industry as a means to increasing the rock permeability and consequently the reservoir’s fluid production rate. Among the different stimulation methods, hydraulic fracturing is known to be the most successful in creating new passageways in the formation. Nevertheless, the benefits of fracturing have been hindered by the handful of events in which poor planning had led to severe seismic activities. Therefore, across the globe, many efforts were dedicated to characterizing fracture creation and propagation in different rocks, not only to provide know-how for further and safer developments in the oil and gas front but also to adapt such findings to the ever-emerging field of geothermal energy recovery. In the course of this work, over 100 papers were studied. The papers included laboratory experiments on various rock types encountered in reservoirs, where parameters such as stress regime, fracture initiation pressure, formation breakdown pressure, volume, and types of fluid injected were monitored. To investigate whether or not such practices had been previously applied in geothermal energy production, a thorough study was also conducted on large-scale experimental setups constructed in the field as well as hydraulic fracturing procedures performed in operational projects, going back as far as a decade. The results show an agreement between laboratory experiments and field operations, yet naturally including individual results from cases where either the lab parameters or field characteristics were extraordinarily unique. Multiple cross-correlations were also performed between different key parameters that play a role in a fracturing process, providing trends that could be intra- or extrapolated for further research and planning. The novelty of this work is the comprehensive analysis of numerous research projects done around the world. As a result, this paper will not only be an informative and yet compacted source of information concerning previous projects, but it also points out the main factors and their relationships which need to be understood to guide a future project to success.

Experimental and Numerical Investigation of 3D Dam-Break Wave Propagation in an Enclosed Domain with Dry and Wet Bottom

Dam-break flood waves represent a severe threat to people and properties located in downstream regions. Although dam failure has been among the main subjects investigated in academia, little effort has been made toward investigating wave propagation under the influence of tailwater depth. This work presents three-dimensional (3D) numerical simulations of laboratory experiments of dam-breaks with tailwater performed at the Laboratory of Hydraulics of Iskenderun Technical University, Turkey. The dam-break wave was generated by the instantaneous removal of a sluice gate positioned at the center of a transversal wall forming the reservoir. Specifically, in order to understand the influence of tailwater level on wave propagation, three tests were conducted under the conditions of dry and wet downstream bottom with two different tailwater depths, respectively. The present research analyzes the propagation of the positive and negative wave originated by the dam-break, as well as the wave reflection against the channel’s downstream closed boundary. Digital image processing was used to track water surface patterns, and ultrasonic sensors were positioned at five different locations along the channel in order to obtain water stage hydrographs. Laboratory measurements were compared against the numerical results obtained through FLOW-3D commercial software, solving the 3D Reynolds-Averaged Navier–Stokes (RANS) with the k-ε turbulence model for closure, and Shallow Water Equations (SWEs). The comparison achieved a reasonable agreement with both numerical models, although the RANS showed in general, as expected, a better performance.

Experimental assessment of secondary stilling basin at the Hričov weir

AbstractOne of the main problems at the Hričov weir is the scour development in the riverbed just downstream. It is caused of construction the size of the stilling basin was significantly shortened. Flow energy is dissipating just partially. Each flood makes scour close to the foundations of the structure, which potentially endangers its stability. A permanent solution was experimentally investigated in the hydraulic laboratory at the 2D model in a scale of 1:40. Different variants of the secondary stilling basins were designed to minimize creating scours. The investigation and its results are described in this paper.

The influence of the water flow on the stability of the coastal slope and adjacent transport constructions

The mechanical behavior of the frozen soil is dynamic and complex. When formulating the strength-to-deformability ratio, it is important to understand the characteristics of the soil, which is being estimated. At the same time different soil samples that have analogical physical characteristics in the unfrozen state may behave differently after freezing and during thawing, as frozen relict and seasonally thawed soils behave differently. All this requires a number of laboratory researches, which will then allow to determine the soil parameters for a specific project. In the hydraulic laboratory, experiments were conducted to study the strength of the different samples of frozen soil under the influence of the water flow and the same load.

Experimental investigation of a free surface oscillation in a model pump-turbine

Hydro power plants provide balancing services to the power grid and the amount is expected to increase in the near future. One of these services is the compensation of reactive power and the regulation of the power factor. Therefore, hydro power units equipped with synchronous machines are operated in so called synchronous condenser mode. During this operation the runner is dewatered and rotates in air above a free surface at the draft tube cone. As a result, a free surface oscillation is excited under some conditions. This paper deals with the experimental investigation of this flow phenomenon. Therefore, model tests are conducted at the hydraulic laboratory of the Institute of Energy Systems and Thermodynamics at TU Wien. The investigated model pump-turbine is equipped with a draft tube cone made of acrylic glass for optical investigations. In addition to the standard instrumentation, fast response pressure transducers are installed at different planes and positions. The machine setup and measurement conditions aim at the investigation of the free surface oscillation and shall prevent other influences. The experiments are performed for both runner rotation directions, different initial water levels at the draft tube and different densimetric Froude numbers. High speed camera recordings are conducted and the amplitude of the water formation is determined by post processing the captured images. In periodic state the frequency of the free surface oscillation is extracted out of the pressure signals. Finally general trends and dependencies are deduced from the acquired data.

Francis 99 CFD through RapidCFD accelerated GPU code

Francis turbines research and development (R&D) requires performance assessment through hydraulic laboratory model testing which can be assisted by auxiliary tools like computational fluid dynamics (CFD), widely used recently. CFD has a history of seeking and requiring ever higher computational performance (HPC) because of the parallelism where Graphics Processor Units (GPUs) have emerged as a major paradigm for solving complex computational problems. However, their implementation to CFD solvers is still a challenge and the tremendous computational power of the GPUs has been wasted. This work presents how the open source RapidCFD code, based on OpenFOAM and ported to Nvidia CUDA, enabled GPUs to be able of running almost entire simulations in thousands of parallel stream cores packed in small form factor hardware in order to solve the incompressible Reynolds-Average-Navier-Stokes (RANS) equations. The simulations were based on a full 3D Francis turbine case which consisted of a grid domain of 23 million cells, including spiral case with stay vanes, distributor, runner and draft tube. CFD results of shaft torque, static pressure and velocity components in steady state deploying a multiple reference frame (MRF) motion approach were compared with available experimental data for main operation conditions at different distributor opening angles: best efficiency operation point (BEP), part load operation point (PL) and full load operation point (HL). The obtained data showed that by transferring directly all the computations to the GPUs, it is possible to make CFD simulations faster compared with central processing units (CPUs). Thus, it is expected to obtain an affordable low computational cost in optimization processes or full range performance evaluations.

Analisis Evapotranspirasi Menggunakan Metode Penman-Monteith pada Vertical Garden

The development of environmentally friendly infrastructure is very important to reduce the environmental damage that has occurred. Environmentally friendly infrastructure can be supported by vertical garden. Plants in vertical garden undergo evaporation process called evapotranspiration process. The evapotranspiration process can be used to find out the needs of water in plants. The method used to obtain the evapotranspiration value is the Penman-Monteith method. The plants used are Plectranthus scutellarioides, Begonia, Coleus, Euodia ridleyi dwarf, Euodia ridleyi, and Chlorophytum comosum. The reference evapotranspiration value in The Hydraulic Laboratory of Sriwijaya University is 4.9826 mm/day and the smallest is 2.1262 mm/day. The reference evapotranspiration value is influenced by temperature, wind speed, and humidity conditions. Based on these three influences, temperature has a greater influence on the reference evapotranspiration. The largest evapotranspiration value of the six types of plants used is the Plectranthus scutellarioides, which is 3.3347 mm/day, the evapotranspiration value of the smallest plant is Euodia ridleyi dwarf, which is 2.6616 mm/day. The location and arrangement of plants and environmental conditions such as temperature, humidity, wind speed affect the amount of evapotranspiration value.

Experimental Design of Physical Unconfined Aquifer for Evaluation of Well Abstraction Effects: Laboratory Approach

In unconfined aquifer water flows in both horizontal and vertical direction when pumping. So its study during pumping action is more complex. Soil type, porosity, hydraulic conductivity and transmissivity are important parameters that control the specific yield, drawdown and radius of influence on aquifer while abstraction. Due to large extraction of water from the aquifer, the water table drops down and may lead to permanent depletion of yield capacity of aquifer. For practical understanding of water being pumped from aquifer and its impacts on water storage the easiest method is experimental approach .So therefore, this study was planned to carry out the well abstraction from unconfined aquifer of homogeneous sandy soil designed as physical model on rainfall simulator at hydraulic laboratory hall of Campus itself. The catchment dimension is 2.2 meter length, 1 meter width and 0.15 meter depth with impermeable base filled with fine sand as per specification. The simulator was adjusted to make horizontal aquifer. The experimental observations were carried out in two conditions, first was well abstraction with no rainfall after saturation and the second is with rainfall even after saturation condition obtained. The two wells were operated for the abstraction of water simultaneously so that the effect of one well to another could be studied. After observation and data collection, for the analysis of hydraulic conductivity Dupit model. Empirical model and relative effective porosity model (REPM) were used for the comparative study. Similarly the radius of influence was estimated by three models (weber,Kusakin and Sichardt). For the estimation of transmissivity of the aquifer Thien model was used. Also the general equation (product of hydraulic conductivity and depth of aquifer) was used. Study showed the suitability of the available theories and governing equations for unconfined aquifer. The most important part of the study was to establish the correlation of drawdown and radius of influence with the time period of well abstraction. From the results the correlation coefficient for time and drawdown was of 90% and for time and radius of influence was 97%.

Behavior of Hydraulic Jump DN a Stilling Basin ii.(Dept.C)

Experiments are conducted in the hydraulic laboratory of the Department of Civil Engineering and Engineering Mechanics of the University of Arizona. The paper shows how establishing the relationship for different flow rates, different velocities and height of tailwater conditions for the U. S. Bureau of Reclamation stilling basin II .It is hoped that this study is useful to the designers of the stilling basin.

Boundary Influence and Flow Characteristics of Orisa and Ala Rivers in Kwara and Ondo States, Nigeria

In this study, the effects of boundary influence on flow characteristics of Rivers Ala and Orisa were investigated. Soil samples were collected from three points each from both rivers namely Glory Parish Area (GPA), Olusola Oke Area (OOA) and Fiwasaye; Aran-Orin Area (AOA), Rore and Omu-Aran on Rivers Ala and Orisa Respectively. A MGG/KL-DCB Portable Electromagnetic Velocity Meter was used to measure the in-situ readings of discharge and velocity at the various points. The sediments collected from the sampling points were placed in the Flume in the Hydraulic Laboratory of Civil Engineering Department, Landmark University. The Flume was then set with the measured parameter (Discharge) for each sampling point to apply the Flume to determine the Velocity for both Rivers at slopes of 0.008 to 0.056 respectively. The velocities obtained at the different slopes were inserted into Manning’s Coefficient equation to obtain the flow characteristics. The relationship between the velocity and Manning’s Coefficient was determined using the Spearman’s rank correlation coefficient. All analyses were done at P-value less than 0.05 level of significance. The velocity varied between 0.0237± 0.0004 and 0.0587± 0.0004 m/s; 0.0542± 0.0004 and 0.0701± 0.0003m/s and 0.0789± 0.0005 and 0.0172± 0.1323m/s for GPA, OOA and Fiwasaye for Ala River and between 0.0751± 0.0007 and 0.1008± 0.0006m/s; 0.0628± 0.0007 and 0.0839± 0.0004m/s and 0.0421± 0.0005 and 0.1076± 0.0004m/s for AOA, Rore and Omu-Aran for Orisa River. The results of the effects of soil boundary influence showed that the velocity was inversely proportional with the Mannings’ coefficient at all sampling points of both rivers if the geometry of the river channel is kept constant. This indicates that areas with high velocities are prone to flooding. Further studies should be carried out on more sampling points on the rivers to confirm flow characteristics of the rivers.

Impact assessment of silting on pipeline capacity

Introduction. Currently, in the construction of engineering systems for various purposes, pipelines made of polymer materials are often used. The ACO Qmax corrugated pipeline was developed as a drainage system for the drainage of surface runoff. The widespread use in practice of corrugated pipes, which have a significantly higher roughness than technically smooth ones, has caused the need to perform a number of calculations that take into account the features of their hydraulic operation. The purpose of the work is to compare the pipeline capacity in the case of partial silting within the corrugation and in the absence of it.
 
 Materials and methods. Due to the complex structure of the inner surface, the resistance of the described polymer pipeline can only be determined experimentally. The hydraulic characteristics of the ACO Qmax corrugated pipeline with partial silting were determined experimentally in the Laboratory of Hydraulics and Hydromechanics of the Moscow State University of ­Civil Engineering (National Research University).
 
 Results. The experiments were carried out under the following conditions: at flow rates Q (from 13.9 to 79.1 m3/h) and the slope of the bottom of the tray i = 0.005; at flow rates Q (from 14 to 89.1 m3/h) and the slope of the bottom of the tray i = 0.01. According to the experimental data obtained, the values of the hydraulic resistance coefficient, the Shezi coefficient, the Manning roughness, and the average flow velocity were calculated. The roughness obtained in a “clean” and partially silted pipeline is compared.
 
 Conclusions. According to the results of the conducted experimental studies, it is concluded that the partial silting of the pipeline within the corrugation of the tray part practically does not affect its hydraulic resistance. A comparison of the experimental values of the average flow velocities in a silted and non-silted pipeline shows that they practically do not differ. Thus, the obtained values of the roughness coefficient can be assumed to be constant for this pipeline.

Simulation of local head loss of drip-irrigation tape with integrated in-line emitters as a function of cross section

Aim of study: To investigate how the cross section of a drip-irrigation tape affects local head loss.Area of study: The work was carried out in the laboratory of Irrigation hydraulics, College of Water Conservancy and Environment, Three Gorges University, Yichang, Hubei province.Material and methods: Tapes with six different wall thicknesses were studied experimentally to determine the relationship between cross-section deformation, wall thickness, and pressure. Based on the experimental results, we determined the factors that influence local head loss in drip-irrigation tapes by numerical simulation and dimensional analysis.Main results: The cross-sectional shape of the drip-irrigation tape varied with pressure: under low pressure, the cross section was nearly elliptical. The cross-sectional shape of the tape strongly influenced the local head loss, which was inversely proportional to the 0.867th power of the flattening coefficient of the drip irrigation tape. We expressed the local head loss of a drip-irrigation tape equipped with integrated in-line emitters by considering the deformation of the cross section. Under the conditions used in this study, when the cross section is circular, the ratio of local head loss to frictional head loss was about 10% but, when the cross section is elliptical, this ratio increased to 15%.Research highlights: The shape of the cross section of a drip-irrigation tape is nearly elliptical under low pressure. Local head loss is inversely proportional to the 0.867th power of that is the flatting coefficient of the drip-irrigation tape. Local head loss is about 1.5 times for elliptical tape than circular tape.

Valorization of briquettes fuel using Pinus spp. sawdust from five regions of Mexico

This research characterized briquettes made with Pinus spp. sawdust without the use of additives. For this purpose, 19 samples of sawdust from different wood industries located in five states of the Mexican Republic were used. The densification process was carried out in a vertical hydraulic piston laboratory briquette machine. The briquettes were made with 40 g of sawdust, at 50 °C, 20 kPa and pressing for 5 min. The results obtained varied as follows: moisture content (4.1% to 7.2%), density (813.9 to 1,014.4 kg/m3), volumetric expansion (7.4% to 37.3%), compressive strength (4.9 to 40.8 N/mm), impact resistance index (46.7% to 200%), ash (0.1% to 1.1%), volatile matter (82.9% to 90.7%), fixed carbon (8.9% to 16.4%), and calorific value (20.5 to 22.8 MJ/kg). The density of the briquettes was within the “acceptable” classification (800 to 1,200 kg/m3). It was observed that, the higher the density, the lower the volumetric expansion, the higher the compressive strength, and the higher the impact resistance index. According to the ash content, the briquettes could achieve international quality. Due to high volatile matter values, rapid combustion of the briquettes with little generation of toxic smoke would be expected. Fixed carbon and calorific value results were acceptable.

Time dependent investigation of the wave induced scour at the trunk section of a rubble mound breakwater

Rubble-mound breakwaters are the most commonly constructed marine structures for various port structures with different areas of usage. Local scour around these structures, which leads to stability losses or even failure, has great importance for the design of these structures both economical and safety perspectives. Within the scope of this paper, wave-induced local scour at the toe of rubble mound breakwaters placed on an erodible seabed was studied both experimentally and numerically. Experiments were carried out on the wave channel in Hydraulics Laboratory of Dokuz Eylul University. Time dependent scour depth and wave characteristics were observed with ultrasonic methods. An equivalent numerical wave channel was used to compare and observe scour mechanism. Regular waves were generated by using Flow3D, one of the advanced computational fluid dynamics (CFD) software. Scour patterns were investigated for relatively coarse and fine seabed material with 1.85 mm and 0.55 mm grain median diameters under various wave scenarios with a breakwater slope of 1:1.5 and 1:1.75 which are widely used in construction. From the experimental and numerical findings obtained from the study, it is understood that the numerical model was found to be compatible with experiments.

Study on Wellbore Stability and Failure Regions of Shale considering the Anisotropy of Wellbore Seepage

The hard and brittle shale formation is prone to collapse and instability, and the penetration of drilling fluid along the bedding reduces the mechanical properties of rock near the borehole wall, resulting in serious downhole accidents. Therefore, in this paper, the geomechanical parameters of the reservoir in the Longmaxi formation of Jiaoshiba were determined by field hydraulic fracturing and laboratory experiments. Then, the stress distribution model of borehole wall under the condition of underbalanced seepage flow is established based on the experimental results obtained by mechanical experiments on underground cores. The instability zone of borehole wall under the condition of underbalance is calculated and analyzed. The results show that the two-way horizontal ground stress of the Longmaxi formation is higher than 2.2 MPa/100 m, and the original ground stress is high. Moreover, the mechanical parameters of the stratified shale stratum matrix and weak surface are significantly different. The cohesion (4.7 MPa) and the angle of internal friction (26.9°) of bedding plane are significantly lower than that of the matrix (7.77 MPa) and the angle of internal friction (46.7°). Hard and brittle shale is easy to be destroyed along the stratification. Under the condition of underbalanced seepage, the mechanical properties of borehole shale can be stable. It is found that when the borehole axis is vertically stratified, the collapse pressure is the lowest, while in other drilling directions, the drilling fluid density needs to be increased by 0.5 g/cm3 to maintain the borehole stability. With the increase of the inclination angle of bedding plane, the wall failure area increases. The results of this study can provide guidance and suggestions for drilling in Jiaoshiba block and other permeable hard and brittle shale formations.

Mathematical and experimental modeling of reverse osmosis (RO) process

This paper provides a mathematical simulation model for the reverse osmosis (RO) process with series elements. A mathematical simulation model was developed based on the mass, material and energy balances considering the concentration polarization. The simulation model is open-source and easy to couple with other computational tools like optimization algorithms and SCADA1 applications. An RO laboratory pilot was also set up in the Hydraulic Lab of Shahid Chamran University of Ahvaz to validate the simulation results. Comparing the results of the simulation model with the experiments and ROSA commercial software, the proposed simulation model functions well and is reliable. The comparisons indicate that the simulation results are over 96% close to ROSA and over 80% close to experimental results.

Results of hydraulic tests of the ACO Qmax system pipeline

Polymer corrugated pipelines are a very promising type of construction that has many advantages over concrete and reinforced concrete structures that are widely used today for collecting and diverting surface runoff from residential areas and enterprise sites. To collect and divert surface runoff from residential areas and enterprise sites, the hydraulic characteristics of the drainage system made of corrugated polymer culverts of ACO Qmax are studied by computational and experimental methods. The experiments were carried out in the laboratory of Hydraulics and hydro-mechanics at different flow rates and different slopes. The kinematic and dynamic characteristics of the water flow in the pipeline were determined: the velocity, the roughness coefficient, and the hydraulic resistance coefficient were measured at different values of the pipeline filling. It is found that the characteristics of the water flow obtained by the computational method using a computer program differ from the experimental values, the reason for which, apparently, in the shortcomings of the computational program and the lack of accuracy of experimental measurements. Experimental studies were conducted to adjust the calculation methods of such pipelines used in the design and verification of hydraulic calculation methods of corrugated pipelines based on the software product ACO Qmax.

Hydraulic and morphological patterns in a riparian vegetated sandy compound straight channel

Emergent vegetation or trees are important riverine features and essential in hydraulic engineering including flood management and river restoration. Clearing up trees along river banks has been pointed out as a contributing factor to the severity of flood damages including financial losses and even fatalities. Thus, the effect of riparian vegetation on river flow must be clearly understood. The hydraulics and morphological patterns in a riparian vegetated sandy compound straight channel were carried out in the Hydraulics Laboratory, School of Civil Engineering, Universiti Teknologi Malaysia. Two-line steel rods with tandem and staggered arrays to simulate as rigid emergent vegetation were placed along the riparian zone of an asymmetrical straight channel. The Manning’s n, depth-averaged velocity, boundary shear stress and morphological changes during shallow and deep floods are discussed in this paper. The findings prevailed that the staggered array riparian vegetation generated 4.5% flow resistance higher than the tandem array. The vegetation also altered velocity distribution which contributed to the boundary shear stress patterns in a compound straight channel. The flow velocity profiles were also related to the morphological changes in the channel.

Проблема надійності водопровідних мереж на прикладі міста Кропивницького

The article presents the analysis of statistical data of the causes of breakages and leaks in water pipes of the distribution network of Kropyvnytskyi. Breakage statistics for pipelines with a diameter of 25 to 1100 mm during the last five years were calculated. As a result of segmental analysis, it was found that the main types of damage to the pipes of water supply system are through fistulas of steel pipes – 54.4% and corrosion – 25.6%; loss of integrity of cast iron pipes on joints – 9.7%, fractures and cracks of cast iron pipes – 6.1%; fractures in joints of polyethylene pipes and other damages – 4.2%. To characterize the reliability of the municipal water supply networks, the pipeline failure flow parameter ω was used. It was defined as the ratio of the number of failures of the water supply network section to the observation period and the length of pipe network sections of the corresponding diameter. The calculation of interval estimates for the failure rate parameter ωо for steel and cast iron pipes of the water distribution network of Kropyvnytskyi was carried out. According to the operational organization 84% of the network was laid using these pipes and analytical expressions were obtained to determine average values of ω0ср depending on their diameter. Significantly higher values of ω0ср were noted in comparison with similar ones given in the literature for other cities, which can be explained by a significant excess of the standard service life of 85% of steel and 50% of cast iron pipes in the water supply network of Kropyvnytskyi. To increase the reliability of water supply networks, it is recommended to implement the experience of European countries and replace 2% of the network per year and use polyethylene pipes. To reduce the failure factor of water supply networks, particularly in those areas where overtime pipes are used, the expediency of partial installation of water-air dampers for pressure fluctuations directly in the pipeline, in which there is a gradual and complete damping of the shock wave. Approbation of a prototype of a hydraulic shock absorber of this design was carried out in the hydraulics laboratory at Central Ukrainian National Technical University and its efficiency and high efficiency at full shock wave damping was confirmed.

Improvement of metrological characteristics of calibrating units of flow measuring devices

The paper presents an analysis of the operation of mass and volumetric calibration devicesused for calibrating flow meters of liquid media in various industries, including model testing ofhydraulic machines in specialized hydraulic turbine laboratories. The aim of the work is shown,which is to analyze the characteristics of deflecting devices and to determine the ways of decreasingthe errors arising therefrom.It was determined that the largest specific weight in the total error of determining the massand volumetric fluid flow rate is the error of the deflecting device, which depends on its dynamiccharacteristics. The system for determining the profile of the liquid flow that fills the measuringtank was improved. A device to control the position of the liquid flow and a method of determiningthe time of filling the measuring tank, taking into account the use of modern laser sensors installedon the measuring tank, is proposed.It is shown that the use of laser position sensors with intersecting beams makes it possible toreduce the measurement error of the measuring tank filling time caused by both low sensitivity offlow position control devices and asymmetry of the flow entering the deflecting device.