Hydraulic Tests Research Articles

Field experiments and main understanding of shale oil hydraulic fracturing

To understand the key processes of hydraulic fracturing in shale oil reservoirs, such as artificial fracture initiation and extension, proppant transportation and settlement, and the influencing factors of post-fracture production, many hydraulic fracturing field tests have been conducted in the United States. Examples include the ConocoPhillips tests and the National Hydraulic Fracturing Experiment. The results have promoted the innovation and development of fracturing technology. A good correlation exists between lithological changes and the roughness of artificial fractures. Although numerous artificial cracks are created, the number that can provide oil and gas seepage is relatively small, determined by the effectiveness of these cracks. The settlement of proppants in actual geological formations involves factors such as geology, lithology, fractures, and stress. The pressure data indicate that when the reservoir pressure drops below the bubble point pressure, the decline in production sharply increases. The key variables affecting shale oil well production include the horizontal well position, well spacing, horizontal section length, and sand addition intensity. These technologies are suitable for the adaptive process of China’s terrestrial shale oil fracturing, promoting the development and rapid increase of shale oil production.

Geomechanical aspects of stabilizing arsenic trioxide roaster waste in cemented paste backfill at the Giant Mine, Canada

Giant Mine, an abandoned gold mine near Yellowknife in the Northwest Territories of Canada, generated significant arsenic trioxide roaster waste (ATRW) during its operations, posing a substantial environmental hazard. This study explored the feasibility of stabilizing ATRW by incorporating it into cemented paste backfill (CPB). Using response surface methodology (RSM), CPB samples with varying mixing ratios were analyzed to identify key parameters influencing strength. Unconfined compressive strength (UCS) tests assessed physical stability, while saturated hydraulic conductivity and computed tomography (CT) analyses examined the microstructure of the CPB. The results revealed that CPB samples prepared with general use (GU) cement exhibited significantly higher strength than those with a GU and lime kiln dust (LKD) mixture. Binder and solid contents were identified as the most critical factors influencing UCS, with binder content having a more pronounced influence. Curing time was found to be non-significant. Higher binder and solid contents correlated with higher UCS values in the CPB samples. The addition of 10% wt. ATRW reduced the UCS by over 30%, particularly in samples with lower binder and solid contents. Although microstructure differences were not evident in saturated hydraulic conductivity tests, CT scans showed increased formation of high-density arsenic-containing materials in samples with the highest UCS, especially those using GU binder. These findings suggest that optimizing binder and solid contents is crucial for enhancing CPB strength and effectively stabilizing ATRW.

Numerical springback prediction for high-strength aluminum alloys based on the sheet metal upsetting test

Springback prediction continues to play a special role in the process design of sheet metal forming processes. During the forming process, elastic energy is stored in the sheet metal, which is released after the tool is opened. The dimensional accuracy and the function of the component in particular can be negatively affected by this. For this reason, the springback is predicted by means of numerical modeling in order to improve the process design. The simulation accuracy depends primarily on the used material model to map the stress-dependent material behavior and the quality of the experimental input data. High-strength aluminum alloys, which have a distinctive springback behavior, have a slightly pronounced tensile-compressive asymmetry. Since tensile and compressive stresses often occur in sheet metal forming processes, the consideration of this effect can lead to an improvement in springback prediction. Besides modeling the yield locus curve for describing the yield strength in the plane stress area, the yield curve data is also relevant for determining the strain hardening behavior. The work hardening is usually characterized by the tensile test or the hydraulic bulge test, which is used to describe the material behavior in the tensile stress state. A promising experimental method for the analysis of the material in the uniaxial compressive stress state is the sheet metal upsetting test. In addition to a local characterization of sheet metal materials, this test also enables the investigation of the material behavior at significantly higher plastic strains than in the tensile test. Thus, in this contribution it is examined to what extent the sheet metal upsetting test is suitable for improving the springback prediction quality of material models in sheet metal forming processes.

Non-invasive detection of hydraulic cylinder leakage using computer vision and time-frequency analysis

ABSTRACT This study presents a meticulous investigation facilitated by a bespoke high-pressure test rig. The rig stands as a cornerstone of the research endeavour, providing the capability to simulate diverse leakage scenarios under controlled conditions. With its capacity to replicate conditions akin to real-world hydraulic systems, including various levels of severity such as healthy operation, moderate leakage and severe leakage. The study delves into the intricate analysis of time-series discharge flow rate signals within this experimental framework. The study utilizes sophisticated signal processing techniques, particularly the Continuous Wavelet Transform (CWT), to observe frequency components and temporal occurrences. Despite prevalent challenges distinguishing between leakage severity levels, the CWT-based analysis provides crucial insights into the dominant low frequencies (2.3–3.3 hz) characterising all leakage conditions. An advanced computer vision-based methodology is devised to address the complexities inherent in leakage differentiation, integrating cutting-edge models such as You Only Look Once (YOLO-V7) and You Only Look Once-Neural Architecture Search (YOLO-NAS). These models are meticulously trained using annotated CWT images of flow rates corresponding to different leakage conditions. Notably, the superiority of YOLO-NAS in terms of both speed and accuracy underscores its efficacy in automated leakage detection. In summary, this comprehensive approach, underpinned by the innovative hydraulic test rig and advanced signal processing coupled with state-of-the-art computer vision techniques, presents a significant advancement in the realm of internal leakage detection in hydraulic systems.

АНАЛІЗ ХАРАКТЕРИСТИК ЛОКАЛЬНОГО НАПРУЖЕНО-ДЕФОРМОВАНОГО СТАНУ З'ЄДНАННЯ МЕТАЛЕВОГО КОМЛЯ З КОМПОЗИТНОЮ ЛОПАТТЮ ПОВІТРЯНОГО ГВИНТА

The article discusses the possibility of modeling the stress-strain state (SSS) of the connection of the metal butt with the composite cylindrical part of the blade using the specialized ANSYS software application and its Composite PrepPost module. Created connection models in ANSYS environment. The optimal designs for connecting the metal butt and composite material have been determined. For a simplified calculation of the connection strength, only the influence of the centrifugal force arising during operation of the screw is taken into account. In the ANSYS software package, a static load of the connection was carried out, which makes it possible to evaluate the nature of the stress distribution in the connection. A butt model and a finite element connection mesh were created. For the calculation, the characteristics of the materials of the blade elements are given. To determine a rational structural-power connection scheme, varying parameters were selected: the number of rows of spikes along the radius, the number of spike belts and the arrangement of the butt spikes. The dependence of the voltage in the composite part of the connection on the arrangement of the butt spikes was obtained. The shape and length of the spike were analyzed. The dependence of voltage on the radius of curvature of the tenon was obtained. The stress-strain state of a tenon-rounded flange is shown in ANSYS. The dependences of voltage on the length of the spike were obtained. The calculation showed that the length of the tenon L has a significant effect on the strength characteristics of the connection between the flange and the composite layer. To determine the rational position of the stud, a calculation was carried out in the ANSYS environment with a shift of all rows of studs by the amount K from the extreme position in engagement with the composite layer and a change in the linear order of the studs to a staggered one. The results of the calculation in the ANSYS environment are presented as a dependence of stress on the displacement K. A flange model is presented, where the stud arrangement is staggered, and the result of the stress calculation in the ANSYS environment. The calculation showed that changing the order of the studs from linear to staggered reduces the maximum stress to 385 MPa. The hydraulic pressure tests confirmed the calculation results. The simulation results showed a significant improvement in the mechanical performance of the joints with minimal design costs.

Experimental and analytical study on the compressive behavior of PMI foam with different densities and cell sizes under intermediate strain rates

Polymethacrylimide (PMI) foam materials have great potential for applications in the field of protective energy absorption owing to their superior compressive properties. Existing studies on the mechanical behavior of PMI foams are limited, particularly for loading at intermediate strain rates. This paper presents a comprehensive experimental study of PMI foam with four different densities under quasi-static and intermediate strain rate compression (0.001 s−1 to 100 s−1). Each density included three different cell sizes to determine their effects on the compressive performance. Loads parallel and perpendicular to the foam rise direction were considered to investigate the anisotropic behavior. Intermediate strain rate tests were conducted using a high-speed hydraulic servo testing machine, which achieved a stable strain rate while ensuring consistent specimen sizes in both quasi-static and dynamic tests. In all the experiments, the compression process was captured using a high-speed camera and the macroscopic deformation mode and microscopic deformation mechanism were analyzed by combining Digital Image Correlation (DIC) and Scanning Electron Microscopy (SEM). The PMI foam with finer cell sizes exhibited an enhanced compression performance. As the strain rate increased, the strain rate effect became more evident in the high-density specimens and an increase in cell size diminished this effect. A modified analytical model incorporating the cell-size correction term was developed based on Gibson and Ashby's model. The modified model exhibited an average error of 4.9 % in the predicted plateau stress of PMI foam with different cell sizes at the same density.

PELAKSANAAN PEKERJAAN STRUKTUR BAWAH BANGUNAN GEDUNG SERBAGUNA GELANGGANG GENERASI MUDA MAJALENGKA

The Majalengka Regency Youth Center Development Project is an important historical milestone for infrastructure development in the Majalengka Regency area. The concept of an oval-shaped building like a stadium gives uniqueness to the design of the foundation of this building. Basically, the substructure is a very vital component for the success of a building, so the author is interested in looking further into the substructure, especially in work methods or work implementation. This research uses a qualitative approach, which can be interpreted as directly describing the work of the lower structures in the project which is used as the research object. The implementation of the lower structure work starts with the piling work and then continues with the pile cap work, carried out in stages using a zone system. In the realization of the implementation of the lower structure work on the GGM project, namely the piling work starting from site preparation, mobilization and set up of HSPD piling tools, measuring pile points, driving piles using the hydraulic jack-in pile method, testing piles, and pile head treatment, continued with the implementation of pile cap work starting from preparation, measurement and bow plank, soil excavation, installation of formwork, reinforcement and casting.

Progressive Failure of Water-Resistant Stratum in Karst Tunnel Construction Using an Improved Meshfree Method Considering Fluid–Solid Interaction

An improved meshfree method that considers cracking, contact behaviour and fluid–solid interaction (FSI) was developed and employed to shed light on the progressive failure of the water-resistant stratum and inrush process in a karst tunnel construction. Hydraulic fracturing tests considering different scenarios and inrush events of the field-scale Jigongling karst tunnel in three scenarios verify the feasibility of the improved meshfree method. The results indicate that the brittle fracture characteristics of the rock mass are captured accurately without grid re-meshing by improving the kernel function of the meshfree method. The complex contact behaviour of rock along the fracture surface during inrush is correctly captured through the introduction of Newton’s law-based block contact algorithms. FSI processing during inrush is accurately modelled by an improved two-phase adaptive adjacent method considering the discontinuous particles without coupling other solvers and additional artificial boundaries, which improves computational efficiency. Furthermore, the improved meshfree method simultaneously captures the fast inrush and rock failure in the Jigongling karst tunnel under varying thicknesses and strengths of water-resistant rocks and sizes of karst caves. As the thickness and strength of water-resistant rock increase, the possibility of an inrush disaster in the tunnel decreases, and a drop in the water level and an increase in the maximum flow velocity have significant delayed effects during the local inrush stage.

CFD analyses and model tests for the optimization design of a large mixed-flow pumping system

Abstract Aiming at the optimization design of the pumping system with mixed-flow pumps, a serial of comparative hydraulic tests, numerical simulation and physical model tests were carried out. The comparative hydraulic test results of suction and discharge passages showed that the design scheme proposed by authors had better flow patterns and smaller hydraulic loss. The comparative CFD analyses indicated that the internal flow in the elbow-type suction box designed by authors were smoother and the flow conditions generated for pump were slightly better, but the flow distribution on both sides of partition pier in the siphon-type discharge passage was obvious poor compared with the scheme proposed by the contractor. Model tests were carried out respectively in the overseas and domestic and the model test results were basically consistent with those of numerical prediction, but the pumping system efficiency in high efficiency zone achieved in model tests was a litter lower than that by CFD. The optimized pumping system was characteristic of higher pumping efficiency and larger flow rate when operated at the designed conditions. The measuring results onsite shown that the best efficiency is more than 80% by use of the optimized pumping system installing mixed-flow pumps with guide vanes.

Unsteady Flow Behaviors and Vortex Dynamic Characteristics of a Marine Centrifugal Pump under the Swing Motion

Due to the effects of swing motion, the performances and internal flow characteristics of marine centrifugal pump undergo some unsteady variations in the marine environment. The hydraulic test system with six degree of freedom parallel motion platform is established to study the pump performance characteristics at the different heel angles of steady roll position and pitch position. The pump head gradually decreases as heel angle increases. The pump head has decreased by 7% to reach the minimum at the 15° heel angle of roll position. At the same heel angle, the head at the roll position is lower than that at the pitch position under the rated flow condition. The fluid in the impeller passage is subjected to the additional inertial force of roll motion or pitch motion under unsteady swing motion, inducing some flow bias phenomena in the velocity field. The unsteady development of flow velocity induces the intense vortex motion, and the shedding and dissipation of interblade vortices are affected. The periodic flow-induced pulsation characteristics obviously appear in the impeller passage. The pulsation periodicity and pressure amplitude are influenced due to the swing motion. The pitch motion induces the greater hydraulic excitation and fluid-induced vibration amplitude. In addition to the pressure pulsation at the low frequencies, the pulsation amplitude at 20 times the shaft frequency is evident under pitch motion.

Anisotropic hydraulic conductivity of as-compacted, bare and vegetated soils

Soils are generally considered anisotropic with respect to hydraulic conductivity, while the evolution of the anisotropy condition is unknown for bare and vegetated soils. Therefore, the main goal of this study is to compare the anisotropic hydraulic conductivity of as-compacted, bare and vegetated specimens. Accordingly, a series of 54 hydraulic conductivity tests was conducted in a custom-made cube triaxial permeameter. The as-compacted specimens were revealed as isotropic because the loosely packed preparation procedure resulted in a dominant flocculent structure. However, a five-fold increase in the anisotropy ratio of bare specimens was measured along the isotropic loading path because of the induced surficial degradation zone formed by irrigation and desiccation processes, as evident in preliminary observations and crack network analysis. The variations in anisotropy ratio compared against void ratio function of vegetated soil generally fall below the corresponding function of the bare soil. The function was revealed to have a crossed nature, varying from sub-isotropic to super-isotropic states, corresponding to the lower and upper bounds of 0·3 and 3, respectively. It was postulated that vegetation impacts the flow differently by reducing the potential of desiccation cracks, creating preferential flow through the propagation of primary roots and clogging flow channels by secondary roots.

Study of freeze-thaw deterioration of saturated and unsaturated hydraulic concrete based on measured strain

In actual concrete water projects, areas such as the back surface, above-water surface, and even areas where the water level fluctuates are in the unsaturated freeze-thaw state. The complexity of freeze-thaw tests of unsaturated hydraulic concrete has thus far prevented a sound understanding of the mechanisms at work in freeze-thaw deterioration of unsaturated hydraulic concrete. Given this situation, this study first compares three different unsaturated hydraulic concrete freeze-thaw test processes (polyurea seal, paraffin seal, and vacuum-bag seal) and then uses the vacuum-bag seal method to implement freeze-thaw tests of unsaturated hydraulic concrete. Afterward, three test schemes (unsaturated sealed freeze-thaw, water-freeze-thaw without air-entraining agent, and water-freeze-thaw with air-entraining agents) are conducted and the mechanisms of freeze-thaw deterioration of saturated and unsaturated hydraulic concrete are evaluated based on the measured temperature and strain of the concrete specimens. The results reveal a continuous and irreversible deterioration leading to the freeze-thaw damage of unsaturated sealed freeze-thaw specimens and water-freeze-thaw specimens with and without an air-entraining agent. After 200 freeze-thaw cycles, the cumulative residual strain of the aforementioned three test schemes reach 47 με, 616 με, and 273 με, respectively. The thermal expansion coefficient of concrete remains relatively constant with increasing freeze-thaw cycles. Water-freeze-thaw specimens without air-entraining agents have a greater thermal expansion coefficient than those with air-entraining agents, and unsaturated sealed freeze-thaw specimens have the smallest thermal expansion coefficient. The frost heave coefficient increases with increasing freeze-thaw cycles, and water-freeze-thaw specimens without air-entraining agents have greater frost heave coefficients than those with air-entraining agents.

Hydraulic fracturing in cement mortar subjected to seepage-sulfate coupled attack under varying pH levels

Cement-based structures are prone to hydraulic fracturing in acidic sulfate and seepage environments, posing a significant safety threat to engineering projects. To investigate the impact of pH levels on hydraulic fracturing in cement-based materials under seepage-sulfate coupled attack, hydraulic fracturing test and splitting tensile strength test have been conducted on cement mortar specimens permeated with Na2SO4 solution. A mathematical model is developed to establish the relationship between the critical water pressure of hydraulic fracturing and the splitting tensile strength at varying pH levels. The results show that the critical water pressure and splitting tensile strength initially increase and then decrease with the increase in erosion duration under pH levels of 7 and 3, while they continuously decrease with the increase in erosion duration under pH level of 1. Furthermore, the peak values of the critical water pressure and splitting tensile strength gradually diminish, which indicates an increased deterioration in hydraulic fracturing resistance with the decrease in pH value. The relationship between critical water pressure damage coefficient and erosion duration can be accurately described by a quadratic polynomial. Overall, the findings of this study can serve as a useful reference for enhancing the structural performance of cement mortar subjected to seepage-sulfate coupled attack at varying pH levels.

Series Multiblood Pump Design With Dual Activation for Pediatric Patients With Heart Failure.

The translational development of pediatric ventricular assist devices (VADs) lags years behind adult device options, negatively impacting pediatric patient outcomes. To address this need, we are developing a novel, series-flow, double-blood pump VAD that integrates an axial and centrifugal pump into a single device. The axial pump is used for initial circulatory assistance in younger patients; then, an internal activation mechanism triggers the centrifugal pump to activate in line with the axial pump, providing additional pressure and flow to match pediatric patient growth cycles. Here, we focused on the design and improvement of the device flow paths through computational analysis and in vitro hydraulic testing of a prototype. We estimated pressure-flow generation, fluid scalar stresses, and blood damage levels. In vitro hydraulic tests correlated well with shear stress transport (SST) predictions, with an average deviation of 4.5% for the complex, combined flow path. All data followed expected pump performance trends. The device exceeded target levels for blood damage in the blade tip clearances, and this must be both investigated and addressed in the next design phase. These study findings establish a strong foundation for the future development of the Drexel Double-Dragon VAD.

Hydraulic tests of a new centrifugal pump with shrouded impeller for extracorporeal membrane oxygenation systems

Hydraulic tests of a new centrifugal pump with shrouded impeller for extracorporeal membrane oxygenation systems

Hydraulic analysis of advanced spillway systems in tailings dams under extreme weather conditions

With the increasing frequency of extreme weather events, heavy rainfall and flooding pose significant pressure on the flood discharge systems of tailings dams. Simple discharge systems are insufficient to meet the flood discharge requirements of tailings dams, while complex discharge systems, with their greater flood discharge capacity, are gradually being promoted. Although complex discharge systems can increase the flood discharge capacity of tailings dams, the flow patterns within the discharge systems become more complex. As a new type of discharge system layout, existing research lacks systematic analysis, and its complex flow characteristics are not clear. This paper relies on the flood discharge system of a large tailings dam to carry out theoretical calculations and derivations of the hydraulic characteristics of the complex flood discharge system. Hydraulic characteristics are observed through hydraulic model tests and verified using numerical simulations. Based on these three methods, a basis for further research on the hydraulic characteristics of complex flood discharge systems is provided. The main results are as follows: (1) The formulas for calculating the discharge flow rate Q under different flow states in the tailings dam design manual are not applicable to complex discharge systems; (2) Formulas for calculating the discharge flow rate Q under different flow states in complex discharge systems are proposed; by comparing model test values and numerical simulation values, the accuracy of the formulas for calculating the discharge flow rate Q in complex discharge systems is verified; (3) If the traditional mode is used to calculate the discharge flow rate Q in complex discharge systems, it is recommended to take the reduction coefficient as 0.55–0.56, and the model test values should also be referred to during flow state transitions.

Research on a new pressure pulsator

Pulsators are widely used to study the dynamic characteristics of liquid flow components. However, it is difficult to adapt the existing actuators to the excitation requirements under high pressures, low temperatures, and toxic media. This study describes the design of a novel pressure pulsation device and presents the results of simulations and experimental tests. The flow field is simulated under a series of working conditions, and the effects of the rotation speed, flow rate, inlet pressure, and gap between the rotor and stator on the peak-to-peak amplitude, spectral amplitude, and flow resistance coefficient of the actuator outlet are analyzed. A prediction model for the corresponding parameters is developed using multiple linear regression. In high-pressure (20 MPa) hydraulic pipeline tests, the excitation device can generate pulsating flow with peak-to-peak amplitudes of more than 7 MPa in the time domain and 2 MPa in the frequency domain. The upstream and downstream regions of the internal flow field are periodically joined and detached by the blade rotation, which results in periodic variations in flow velocity and pressure. The relative error between the model predictions and the three-dimensional simulation and experimental values is less than 7%, satisfying industrial requirements. This work facilitates a solution to the problem of dynamic excitation when analyzing the response characteristics of fluid equipment in high-pressure pipelines and provides a method for forecasting actuator output effects.

Reliability analysis of 50000 kN hydraulic support test bench under shrinkage test conditions

The large mining-height hydraulic support test-bed serves as a crucial tool for heavy hydraulic support factory inspections and type testing. With the successful development of the ZY29000/45/100D hydraulic support, the need for a large high-mining hydraulic support test-bed has become evident. This paper combines the theory of rigid-flexible coupling in virtual prototypes and ADAMS multi-body dynamic simulation technology to analyze the strength of the 50,000 kN hydraulic support test-bed. ANSYS classic modules were employed to address the flexibility of key components within the test-bed. The fatigue life of the test-bed was analyzed using NSOFT software, the von Mises yield criterion, and the Goodman modified curve. The S-N curve of material parameters for the test-bed components was used to conduct a shrinkage test. The results indicate that the lowest position is the most vulnerable during the shrinkage test. Among the key components, the stress on the pin bearing is 356.6 MPa, which is 167.9 %, 123.3 %, and 41.6 % higher than that of the pillar, movable beam, and base, respectively. The fatigue life of the base under low, medium, and high shrinkage conditions is1.1×107, 4.0×108, and 1.7×108, with damage values of 8.8×10-8, 2.5×10-9, and 5.7×10-9, respectively. The base’s life under low shrinkage conditions is the shortest, followed by that under high shrinkage conditions. These research findings provide technical guidance and an optimization foundation for the successful development of a 50000 kN hydraulic support test-bed. They also offer a new method and approach for analyzing and predicting the fatigue life of key components in large-scale industrial and mining equipment operating under complex conditions, with promising practical applications.

TRACE assessment of density wave instability onset with void reactivity feedback under natural circulation

Density wave oscillation (DWO) is an important safety concern for boiling water reactors (BWR) due to their high void fraction in the core. Power extensions to existing reactors such as the Maximum Extended Load Line Limit Analysis Plus (MELLLA+) lead to increase susceptibility of DWO-type instability following an anticipated transient without scram (ATWS). Experiments performed at the Karlstein Thermal Hydraulic Test Facility (KATHY) have reproduced the reactivity feedback mechanism in BWRs under ATWS conditions. Using a neutronics module simulator, the KATHY facility was able to provide data on the effect of different neutronic parameters on DWO onset. This paper serves to assess the capability of the thermal-hydraulics code TRACE V5P7 for simulating DWO onset and development under natural circulation with neutronic feedback. A model of the KATHY natural circulation facility is created in TRACE and a reactivity feedback mechanism is implemented using a manual control scheme to simulate the parametric effects provided by the tests. This comparison allows for an assessment of the TRACE code as well as a better understanding of the instability mechanisms and behavior under the given conditions.

Hydraulic Model Tests for a Pontoon-Type Floating Structure with a Horizontal Damping Plate

In this study, hydraulic model tests were conducted to investigate the effect of a horizontal damping plate on the motion of the pontoon-type floating structure. The floating structures with and without the horizontal damping plates were fabricated with the scale of 1/20 and their motion responses to the regular and irregular wave conditions were investigated. From the comparison for the responses of each model with 16 wave conditions, it could be known that the damping plate made the response of the the pontoon to be smaller by about 5 to 10 % compared with the normal rectangular pontoon.