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Fluid injection is a common practice in the oil and gas industry found in many applications such as waterflooding and disposal of produced fluids. Maintaining high injection rates is crucial to guarantee the economic success of these projects; however, there are geomechanical risks and difficulties involved in this process that may threat the viability of fluid injection projects. Near wellbore reduction of permeability due to pore plugging, formation failure, out of zone injection, sand production, and local compaction are challenging the effectiveness of the injection process. Due to these complications, modeling and simulation has been used as an effective tool to assess injectors' performance; however, different problems have yet to be addressed. In this paper, we review some of these challenges and the solutions that have been proposed as a primary step to understand mechanisms affecting well performance. [ABSTRACT FROM AUTHOR]

The dynamic response and operational reliability of high-speed solenoid valve (HSV) for diesel engine injector are the main indicators to measure their performance. At high-frequency, the eddy current energy and Joule energy generated by the HSV will be converted into heat, which has a significant impact on the service life of HSV. The optimization of HSV involves the interaction between energy loss and the dynamic response of HSV. To optimize the HSV dynamic response time considering energy loss, the HSV work process simulation model was established in this paper, and the model was verified based on armature lift experimental data. Without changing the structural parameters of the HSV, the four parameters of electroconductibility, spring stiffness, damping coefficient, and coil resistance were selected as the key parameters affecting the dynamic response and energy loss. The response surface models (RSMs) of opening response time, closing response time, eddy current energy and Joule energy of the HSV were constructed by using the smoothing spline-analysis of variance method. The multi-objective cooperation optimization of HSV under the interaction of dynamic response characteristics and energy loss was completed by using non-dominated sorting genetic algorithms. After optimization, the opening and closing response times of HSV were reduced by 15.1% and 16.6% respectively, while the eddy current energy and Joule energy were reduced by 5.2% and 48.4% respectively. In this paper, the dynamic response and energy loss were jointly optimized. The presented results provide theory instruction for multi-objective cooperative optimization of HSV. [ABSTRACT FROM AUTHOR]

As the core component of a water conservancy sprinkler irrigation system, the self-priming jet pump is required not only to meet performance criteria for self- priming but also to align with the growing trend toward compactness in sprinkler irrigation systems. This paper takes the short compact self-primingjet pump as the research object whose injector is perpendicular to the main flow direction of the impeller inlet in order to reduce the volume of the jet pump and adopts the method of numerical simulation combined with experimental validation to study the effect of vertical arrangement of the injector on the hydraulic characteristics and operational instability of the self-priming jet pump. The results show that compared with the traditional hydraulic structure, the front injector leads to a significant reduction in the applicable flow range of the short jet pump. The hydraulic efficiency of the jet pump is notably inferior to that of traditional pumps across various flow conditions. This discrepancy arises from the eccentric rotation induced by the front-mounted injector, leading to pronounced circumferential asymmetry in the media flow within the individual impeller channels. Consequently, this asymmetry contributes to increased hydraulic losses in the flow channel. At the same time, the smaller overflow area within the injector enhances the turbulent flow characteristics of the medium, leading to increased instability of the subsequent flow field. This induces the generation of unwieldy low-frequency pressure pulsation signals within the flow channel, which are more readily propagated throughout the sprinkler system. In the practical application of short jet pumps, the circumferentially asymmetric distribution ofthe media flow in the impeller channel may result in the eccentric rotation of the rotor, thereby diminishing the service life of the pump. Furthermore, the complicated low- frequency signals will induce low-frequency vibration of the hydraulic sprinkler system, reducing the operational stability of the sprinkler system. [ABSTRACT FROM AUTHOR]

Operational amplifiers (op amps) are fundamental blocks that find wide application both as stand-alone devices and as crucial blocks embedded in various Systems on Chips (SoCs). Achieving high defect coverage, as well as performing defect localization in these circuits, has proven to be a difficult/expensive task, even with sophisticated testing circuitry. The ISO 26262 standard for functional safety (FuSa) includes the stringent requirement that an automotive IC must have a very high defect coverage. This reinforces the need to ensure the functionality of analog and mixed (AMS) circuits, especially in mission critical applications. This paper presents an all-digital op amp defect detection, diagnosis, and localization method that can be used both for production and in-field tests and discusses various implementation of the proposed method. We validated our results using extensive transistor-level simulations of multiple op amp architectures using TSMC 180 nm technology. Across op amp architectures and multiple implementation approaches, we achieved a worst-case and best-case defect coverage of 94.5% and 99%, respectively. Furthermore, in this work, we also propose a defect diagnosis and localization strategy using recorded bit streams from states of digital injectors and detectors. [ABSTRACT FROM AUTHOR]

Retinal vein cannulation involves puncturing an occluded vessel on the micron scale. Even single millinewton force can cause permanent damage. An ophthalmic robot with a piezo-driven injector is precise enough to perform this delicate procedure, but the uncertain viscoelastic characteristics of the vessel make it difficult to achieve the desired contact force without harming the retina. The paper utilizes a viscoelastic contact model to explain the mechanical characteristics of retinal blood vessels to address this issue. The uncertainty in the viscoelastic properties is considered an internal disturbance of the contact model, and an active disturbance rejection controller is then proposed to precisely control the contact force. The experimental results show that this method can precisely adjust the contact force at the millinewton level even when the viscoelastic parameters vary significantly (up to 403.8%). The root mean square (RMS) and maximum value of steady-state error are 0.32 mN and 0.41 mN. The response time is below 2.51 s with no obvious overshoot. [ABSTRACT FROM AUTHOR]

The backflow of high-temperature products in an engine's combustion chamber is a key issue which can significantly reduce combustion efficiency. This is particularly problematic for hypergolic propellants, as the high-temperature products may still contain fuel or an oxidizer. If either the fuel or the oxidizer backflows into the manifold of the other, it can easily lead to micro-explosions, thereby creating a threat. To address this problem, this paper proposes a new design of an anti-backflow injector, aimed at effectively preventing the backflow of combustion products to the propellant manifold. A steady-state, non-reactive Computational Fluid Dynamics (CFD) model is employed to evaluate the steady internal flow characteristics of the proposed anti-backflow injector. Additionally, a complementary transient, multiphase fluid dynamics simulation is carried out to assess the response characteristics of the anti-backflow injector. Our analysis focuses on the response characteristics of the concave valve core. The study also explores the impact of different expansion port angles on the injection effect, finding that the vortex diameter at the injector outlet is positively related to the expansion port angle. It is also shown that the injection angle becomes more stable as the expansion angle increases. When the expansion port angles are 10° and 20°, the injection angles show similar trends. In terms of anti-backflow effect, taking the injection stiffness of 150% and a time range of 300 µs as examples, the response time of the anti-backflow models with expansion ports of 10°, 15°, and 20° is increased by 67 µs, 99 µs, and 213 µs, respectively, compared to the base models with the same expansion angles. Meanwhile, when the injection stiffness is 50%, the response time of the anti-backflow models with expansion ports of 10°, 15°, and 20° is increased by 207 µs, 210 µs, and 207 µs, respectively. When the injection stiffness is 20%, the response recovery speed of the anti-backflow models with expansion ports of 10° and 15° is increased by 41 µs and 96 µs, respectively. However, the performance of the anti-backflow model with a 20° expansion port is 216 µs of the base model. The optimized design of the anti-backflow injector has potential applications in solving the propellant backflow problem and contributes to the advancement of combustors. [ABSTRACT FROM AUTHOR]

The homogeneous field measurement of internal flow and spray of internal combustion engine injector nozzles under high pressure has always been one of the difficulties in experimental research. In this paper, an actual-size aluminum alloy nozzle is designed, and the simultaneous measurement of internal flow and near-field spray is successfully realized with the help of synchrotron radiation X-ray phase contrast imaging technology under an injection pressure of 30~90 MPa. For a 0.25 mm aperture nozzle, different radii of the inlet corner can induce different cavitation layer thicknesses, and the measured flow section shrinkage ratio is 0.70. The flow characteristics in the nozzle are entirely connected to the jet characteristics, indicating a tight correlation between internal flow and jet morphology. Finally, the internal cavitation of the nozzle was studied by the CFD simulation, and the simulation results are in good agreement with the experiment. [ABSTRACT FROM AUTHOR]

This research paper discusses the Field Development Plan (FDP) - 2020 of a brownfield which recommends drilling 3 infill producers to boost oil production. The study aims to address the mismatch in Gas Oil Ratio (GOR) in the existing model by incorporating uncertainty analysis in the simulation model. The methodology includes a top-down approach through the synthesis of the pressure-production behaviour, the evolution of GOR in wells/fields and the possible presence of a hidden gas cap. The findings of the present study demonstrate that by incorporating a small initial gas cap in the up-dip area of the field that any well has not penetrated, a significant improvement in GOR match and its early evolution in wells/fields are beautifully captured. The introduction of the initial gas cap has necessitated re-positioning and shifting of 3 infill producers away from the gas cap to maximise oil production. A novel two-pronged approach has been recommended for enhancing the water injection rate by 3-4 folds through a combination of a powered water injection system (already in place) and conversion of one of the existing injectors to a dump flooder on a pilot basis to ensure uninterrupted water injection in the field given the frequent power outages in the area. [ABSTRACT FROM AUTHOR]

Because of the long horizontal length and reservoir heterogeneity, water production and injection are different along different locations of a horizontal well. Besides, the conventional models for inferring interwell connectivity between directional wells are not suitable for horizontal wells. In this paper, a new model for inferring interwell connectivity between horizontal wells is built and a new water injection string is presented which can meet the demand of water injection of different locations for a horizontal well. Based on the conventional water injection string, a water distributor working cylinder was installed to respectively distribute water to root and toe of a horizontal well. A horizontal well can be considered as several directional wells with different physical properties such as permeability and porosity and so on. The reservoir is characterized as a coarse model consisting of a number of interwell units which is controlled by any two directional wells. Injection and production data were used to infer interwell connectivity and geological characteristics. The results obtained from the new proposed model are in consistent with the oxygen activation of injectors. Interwell connectivity coefficient of each injector was calculated and the preponderance flow paths were found. [ABSTRACT FROM AUTHOR]

An intense narrow-band terahertz (THz) radiation source has been designed to generate a broad tuning range of radiation frequencies between 0.5 THz and 5.0 THz. The THz radiation is produced when a short-bunch electron beam propagates through an undulator. To achieve high-power peak radiation, the source requires high-brightness electron beams with low beam emittance and short bunch length. A proposed design for the photocathode RF gun used as the electron source is presented. The gun with high mode separation and high Q-factor can be achieved for producing a good beam quality. The beam dynamics of the injector have been preliminarily optimized using the software ASTRA and Elegant, investigating the impact of laser pulse shape on electron beam quality. The results of the beam dynamics studies are comprehensively discussed in this paper. [ABSTRACT FROM AUTHOR]

The forward variable area bypass injector (FVABI) is a key component of double bypass variable cycle engine (VCE) to achieve mode transition and bypass ratio adjustment. In this paper, an experimental system for FVABI was constructed based on the analysis of relevant experimental theories, and then the experiments on FVABI were carried out for a specific working state in double bypass mode of VCE and for the comparison working states with different area ratios and different back pressure ratios. The results showed that the FVABI designed in this paper meets the requirements of VCE at this working state. The analysis of the influence of area ratio and back pressure ratio on the injection coefficient showed that the first bypass valve and back pressure were effective means to control the mass flow of FVABI. [ABSTRACT FROM AUTHOR]

Background: Anaphylaxis is a sudden multisystem allergic reaction which may result in a fatal outcome if not treated promptly. Guidelines worldwide suggest intramuscular adrenaline as the first‐line treatment for anaphylaxis outside a perioperative reaction. Adrenaline autoinjectors (AAIs) are widely used self‐administrable devices, especially in community settings. Different commercial AAIs have been authorized to be marketed in Europe. For an AAI to be efficacious, a rapid adrenaline delivery in patients, including those who are overweight or obese, resulting in an optimal cardiovascular (CV) response, is a key feature. AAIs are designed to achieve this requirement, which is reflected in their differing functional properties such as primary container selection, drug delivery mechanism (cartridge‐or syringe‐based), needle length, needle gauge, and adrenaline dose (150 μg, 300 μg, or 500 μg). However, the differences in functional properties across these devices may play a critical role in achieving these requirements as well as the differences in ergonomics in the handling of these devices. The purpose of this review: Considering the dynamic pharmacokinetic/pharmacodynamic (PK/PD) profiles of different AAIs marketed in Europe and their effect on adrenaline delivery, the expert panel, also serving as author for this paper have carried out a detailed analysis of the PK/PD profiles of four AAIs, namely, Anapen, Emerade, EpiPen, and Jext, to delineate the adrenaline delivery and their subsequent physiological effects on the backdrop of device characteristics, dose strength, and the skin‐to‐muscle distances of the participants. [ABSTRACT FROM AUTHOR]

The Hefei Advanced Light Facility (HALF) injector comprises 40 S-band 3-m traveling wave accelerating structures, capable of delivering electrons with a full energy of 2.2 GeV into the storage ring. To mitigate emittance degradation caused by field asymmetry in the coupler cavity, the coupler design incorporates a racetrack and a short-circuit waveguide. This paper introduces the microwave design and provides the parameters of the HALF accelerating structure. Two design methods for couplers were compared, and the effectiveness of using the undercoupling (for which the coupling coefficient β calculated by Kyhl's method is less than 1) to match the output coupler was experimentally demonstrated. The nodal-shift method and bead-pull method were used to test and tune the structures of different output coupler designs during the cold test, demonstrating the tuning results under actual conditions. Experiments were conducted under different load conditions to calculate the local reflection coefficient of the output coupler. The results show that both the accelerating structure design and the tuning results meet the HALF requirements. [ABSTRACT FROM AUTHOR]

A proposal has been made for the construction of a new generation of high-luminosity electron-positron colliders known as the Super Tau-Charm Facility (STCF) in China. The STCF aims to achieve a luminosity exceeding 0.5×1035cm−2s−1 and will operate within a center-of-mass energy range of 2 to 7GeV. Given the design challenges of the STCF collider ring, swap-out injection has been proposed as an alternative method for achieving the desired luminosity. Consequently, the STCF injector will explore both off-axis injection and swap-out injection methods concurrently. This paper will detail the ongoing research progress on these two injection techniques. [ABSTRACT FROM AUTHOR]

Hydrophilicity/hydrophobicity is a common physical property of the material. Water droplets roll on lotus leaf, and a lot of dust and dirt on the surface of the lotus leaf will be taken away, playing a certain cleaning role. The hydrophobic surface has drag reduction effect that would produce slip on the hydrophobic wall. There are some studies on hydrophilicity/hydrophobicity in channels, most of which focus on the effect of surface drag reduction and heat transfer on microchannels. However, few people pay attention to the effect of the hydrophilicity/hydrophobicity of the injector inner wall on the atomization performance. In this paper, three groups of the open-end swirl injector with different tangential channels were designed to study the effect of hydrophilicity/hydrophobicity on atomization performance. The hydrophobic coating was prepared and used on the inner wall of the injector, and the atomization experimental system was built. In the experiment, the liquid film thickness was measured using the conductance method. Details of the liquid film breakup and spray development were recorded with a high-speed camera. The average droplet diameter was measured by the Malvern particle size analyzer. The atomization performance of injectors with different tangential channels on the hydrophilicity/hydrophobicity was compared, and the effect of the velocity profile on the jet stability is discussed. [ABSTRACT FROM AUTHOR]

This paper explores the effects of six different cases of port water injection on the combustion, knock suppression and emissions of a supercharged gasoline direct injection (GDI) engine through numerical simulation. The six different intake port water injection cases included three vertical distances from cylinder center to water injector and two different injection directions. The results showed that cases 2 and 4 allowed more water and air to enter the cylinder and thus suppressed the knock, so the pressure oscillation was small. Case 2 had the largest turbulent kinetic energy in the center of the cylinder, which in turn facilitated the propagation of flame to the cylinder wall and suppressed the knock. The water injection cases shortened the combustion delay period compared to the no water cases. At the same time, the strong low temperature reaction of the end mixture produced a large amount of CH2O that decomposed into HCO. A high concentration and a large area of HCO distribution can predict the occurrence of a knock. In addition, the water injection cases (except for case 6) reduced the in-cylinder soot, unburned hydrocarbon (UHC) and CO emissions compared to the no water cases, but it increased NOX emissions. [ABSTRACT FROM AUTHOR]

The paper is devoted to the IPM-2 ion source ion-optical system preparation for the plasma heating experiments with a neutral beam in the Globus-M2 spherical tokamak. Within the framework of this work, a complete renovation of the ion-optical system of the ion source was carried out, including its assembly, adjustment, and testing. To assess the quality of the work performed, measurements were made of the main electrical parameters of the high-energy beam, its energy spectrum and signals from secondary emission probes. Based on the data obtained, the beam power distribution profile and its characteristic dimensions are reconstructed, and the relative concentrations of the energy components of the beam are calculated. [ABSTRACT FROM AUTHOR]

The flow inside the orifices in diesel injector largely determines the injection characteristics, which further affects the performance of the diesel engine. In this paper, numerical simulation is conducted to characterize the fuel flow with characteristics of two-phase cavitation, high speed, high pressure, high turbulence intensity, and high viscosity in two crucial orifice locations. The OZ orifice is selected as a benchmark to select the appropriate turbulence model and cavitation model. The simulation results from different turbulence and cavitation models are analyzed, and the combination of the realizable k–ε turbulence model and the Zwart–Gerber–Belamri cavitation model proves to be superior. Then, based on the validated models, the compressibility and non-isothermal characteristics of the fuel and two geometric parameters of the nozzles in an injector are emphatically discussed to depict the cavitation flow. The results suggest that the compressibility and non-isothermal characteristics of fuel affect the mass flow rate, fuel flow velocity, and cavitation extent within the orifices with a maximum deviation of the mass flow rate of 7.1%. However, their influence on the orifice flow coefficient is relatively minor with a maximum deviation of 0.8%. The mass flow rate and flow coefficient are both positively correlated with the rounded edge radius and taper coefficient. A greater rounded edge radius and taper coefficient can lead to a better fuel flow capacity in the nozzle orifice. [ABSTRACT FROM AUTHOR]

This paper shows the design of an injector, using carbon nanotubes as inkjet material, implemented in a 3D printer. According to the available literature, few injectors are capable of depositing material. Due to the lack of information, the central part of this research is to develop a suitable device for ink injection that is capable of applying the Fused Deposition Modeling (FDM) method to print nanomaterial ink. The injector was designed using a CAD program based on an open-source desktop 3D printer, which allows it to be modified according to the needs of the injector. This prototype was manufactured in aluminum alloy 7075T6. Computational fluid dynamics (CFD) were carried out to analyze the behavior of the fluid when it passes through the injector, obtaining parameters such as pressure, velocity, and vorticity. An experimental matrix of the injector operation was carried out to achieve an adequate printing speed. The results show that the optimum speed was 250 ms, considering that a temperature of 100 °C is needed in the heated bed to dry the ink so that it does not undergo expansion. [ABSTRACT FROM AUTHOR]

This paper proposes a drop-on-demand (DOD) system that can produce single droplets of highly repeatable size in the order of 2 mm. This system utilizes an on-the-shelf solenoid injector used in automotive applications. The design methodology is explained along with the necessary measurements and numerical simulations of droplet generation. The invention consists of a solenoid injector that produces monodisperse single or in-series droplets with the help of a developed pulse width modulated signal generator. Mass per injection is measured over a range of supply pressures and injection durations to find the operation window to generate 2 mm droplets. Later, various nozzle geometries are designed and tested by flow simulations. The contracting nozzle is found suitable for generating single droplets, so the design is implemented at the tip of the solenoid injector. The effects of different opening times, pressures, and nozzle's orifice diameters were tested to observe the operating window of the newly designed DOD system and the repeatability of generated droplets by utilizing a coherent circular Hough transform image processing algorithm to measure droplet sizes. The standard deviation of measured diameters is less than 5% of the mean droplet diameter, which is in the range of 1.68–2.07 mm. Next, the voltage and current signals are measured per injection, and exact instants for the initiation and ending for both opening and closing are determined to construct transient mass flow rate functions for flow simulations in which the dependence of droplet formation on the speed of closing is revealed. The numerical and experimental results indicate the repeatability and consistency of the invention. [ABSTRACT FROM AUTHOR]

The present paper experimentally verified and computationally explained an improved design concept of the spray combustion of a gas–liquid pintle injector with variable swirl intensities. By pintle injector, we mean a promising injector for the throttleable engines with variable thrust capacities, which features the moveable pintle continuously controlling the mass flow rates of fuel and oxidizer where the radial and axial flows encounter to form a spray cone and spray atomization. First, the cold flow test was conducted to study the swirl effects on the spray angle, followed by the combustion test to study the total pressure and the specific impulse under different swirl intensities. The results show that the swirl enhances the combustion performance by increasing the total pressure and specific impulse. Second, the swirl-assisted spray was numerically simulated based on a validated volume-of-fluid method to explain the experimental findings. The diameter distribution and spatial distribution of dispersed droplets were analyzed by the Sauter mean diameter (SMD) and the Voronoi tessellation, respectively. The results show that the swirl significantly promotes the breakup of liquid jet or film, producing smaller SMDs and a more uniform spatial distribution of dispersed droplets. The consolidated correlation between the non-reacting spray characteristics and the combustion performance suggests that the proposed methodology can be used to fast prescreen pintle injector designs. [ABSTRACT FROM AUTHOR]

Whether intentionally or unintentionally, waterflooding always takes place under fracturing condition in tight reservoir because of the extremely limited water absorption ability of the formation. Recently, we proposed a novel workflow, including real-time monitoring, formation testing analysis, and dynamic production analysis, to timely and effectively identify the initiation of waterflood-induced fractures (WIFs) and characterize the waterflooding behaviors for a well group. In this paper, we further provide a supplementary study to evaluate the waterflooding performance from the well group to the field basis. The utilization factor (UF) is first estimated on the basis of injection/production data by material balance theory, which provides an overall picture of water injection efficiency every year. Then, the areal (straightforwardly showed by water cut and formation pressure distributions) and vertical sweep (includes the water absorption in injectors and water breakthrough in producers) behaviors are studied to investigate the waterflooding characteristics and residual oil distributions. Lastly, three key influence factors are detailedly discussed: sand body connectivity, WIFs, and injection and production correspondence. Combining the previous work for the single well group, and the study in this paper to field basis, one can have a better and much more comprehensive understanding of the waterflooding performance and then thus take the corresponding adjustment measurements to improve waterflooding effectiveness. [ABSTRACT FROM AUTHOR]

This paper presents an approach to optimize the recovery factor and sweep efficiency in a waterflooding process by automating the optimum injection rate calculations for water injectors using streamline simulation. A streamline simulator is an appropriate tool for modern waterflood management and can be used to determine the dynamic interaction between injector and producer pairs, which will vary over time based on sweep efficiency and operational changes. A streamline simulator can be used to identify injectors, which are not supporting production and contributing mainly to water producing wells. Streamlines illustrate natural fluid-flow paths in the reservoir, which are based on fluid properties, rock properties, well distribution and well rates across the reservoir. A bundle of connected streamlines can provide the oil in place between an injector/producer pair at any given time during a simulation run. Thus, the well pair recovery factors for each injector/producer pair, the produced water cut and the weighting factor for each injector are determined. Multiplying this weighting factor by the injection rates determines the new injection rate for each injector. For a well pair water cut that is lower than the average field water cut, the injection rate will be increased and vice versa. Given a finite volume of injection water, there will be a re-allocating of water from a well pair with a low recovery factor and high water cut and redistributing the water to injectors supporting low water cut producers, thus maximizing the recovery factor and reducing the field water production. The described approach is an automated procedure during the reservoir simulation run, making it appropriate for full field waterflood optimization with many injectors and producers in high-resolution heterogeneous brown reservoirs. This approach can reduce the water cut and increase the recovery factor and extend the life of the waterflooded oil fields. It was initially tested with a synthetic model and later with an actual reservoir model, which will be described in this paper. [ABSTRACT FROM AUTHOR]

Small naval vessels are equipped with high- and medium-speed engines with low diagnostic compliance. Faults in fuel installations are the most common cause of failure or inability to perform operational scenarios adequately. Identification of injector damage is severe as small engines are not equipped with indicators and thermocouples to measure the overall exhaust gas temperature in the exhaust manifold. The paper presents a vibration method for assessing the technical condition of a fuel installation. The proposed method is non-invasive and allows the indication of a damaged injector within a relatively short time. The paper presents simulation results verified with stand-bed tests. The research aimed to show the sensitivity and uniqueness of vibration symptoms to changes in the technical condition of fuel injection pumps. The conducted experiment confirmed the possibility of using vibration tests in the professional diagnostics of the fuel installation. These results are essential for the use of marine engines that do not have indicator valves. [ABSTRACT FROM AUTHOR]

In the paper, an attempt was made to computationally demonstrate the effect of the plunger pressure stiffness on the opening and closing times of the low-pressure gasphase injector as a filling of the research gap in this subject. Based on the presented mathematical model describing the operation of the injector, firstly the results were related to the manufacturer's technical data showing a shorter time to full opening by 2.77% and a longer time to full closing by 0.50%. On this basis, it was considered that the proposed model can be used for comparison purposes. In the assumed range of compression spring stiffness (100... 2000) N/m, it was shown that as the stiffness increases, the time to fully open decreases by 18.85%, while the time to fully closed decreases by 80.17%. Additionally, it is shown that the time-cross section as the stiffness of the compression spring increases can decrease up to 35.21% from the initial value. The obtained results can be useful in modeling the operation of an internal combustion engine or in the operational assessment of the gas injector condition. [ABSTRACT FROM AUTHOR]

Correct fuel atomization is an important parameter in the process of preparing a combustible mixture. Distortions of the atomization can lead to unfavorable effects in the combustion process. This paper presents an analysis of the fuel atomization characteristics of high-pressure fuel injector tests. Optically tested injectors were previously tested in a 48 h engine test carried out in accordance with the CEC F-113-KC procedure, using alternative fuels with ethanol blends. As a result of engine tests on fuels containing various amounts of ethanol admixture, the injectors became contaminated. The effect of the deposits on the geometric atomization indicators was determined. This paper focuses on analyzing the area of the atomized spray in a constant volume chamber at different parameters, reflecting real operating conditions. We found that the addition of ethanol (20%) increases the observed spray area for all test points. Complementing the quantitative results is a qualitative analysis of fuel atomization for injector tests previously run on varying fuels. [ABSTRACT FROM AUTHOR]

This paper presents a compact analog system-on-chip (SoC) implementation of a spiking neural network (SNN) for low-power Internet of Things (IoT) applications. The low-power implementation of an SNN SoC requires the optimization of not only the SNN model but also the architecture and circuit designs. In this work, the SNN has been constituted from the analog neuron and synaptic circuits, which are designed to optimize both the chip area and power consumption. The proposed synapse circuit is based on a current multiplier charge injector (CMCI) circuit, which can significantly reduce power consumption and chip area compared with the previous work while allowing for design scalability for higher resolutions. The proposed neuron circuit employs an asynchronous structure, which makes it highly sensitive to input synaptic currents and enables it to achieve higher energy efficiency. To compare the performance of the proposed SoC in its area and power consumption, we implemented a digital SoC for the same SNN model in FPGA. The proposed SNN chip, when trained using the MNIST dataset, achieves a classification accuracy of 96.56%. The presented SNN chip has been implemented using a 65 nm CMOS process for fabrication. The entire chip occupies 0.96 mm2 and consumes an average power of 530 μW, which is 200 times lower than its digital counterpart. [ABSTRACT FROM AUTHOR]

A control survey technique using a laser tracker and a digital level was introduced to the KEK e−/e+ injector linac in 2020. Control surveys are continuously demonstrated during the machine's downtimes every summer. Analysis of the two-year data reproduces their trends in terms of the fiducial points on the beam line. In our paper, we report on systematic coordinates and their error distributions evaluated by a control survey, compare them with a numerical survey simulation, and discuss newly encountered issues. [ABSTRACT FROM AUTHOR]

This paper presents a numerical simulation analysis of the flow and combustion characteristics of a fuel-rich LOX (liquid oxygen)/kerosene gas generator in an ATR (air turbo rocket) engine, examining the effects of local parameters on the combustion flow field and performance. The analysis considers variations in unit injector mixing ratios and unit mass flow rates. The results indicate that as the mixing ratio in the inner-ring injectors increases (while the mixing ratio in the middle-ring injectors decreases), the oxygen concentration area near the axis zone and the 50% radius zone of the gas generator expands. Conversely, the kerosene concentration area near the axis zone decreases while gradually increasing near the 50% radius zone. In the flow direction section, there is an inverse relationship between the variation trend of local temperature and the oxygen concentration in the local area. As the oxygen concentration increases, the temperature decreases. The temperature distribution across the cross-section of the gas generator exhibits a circular pattern. When the mixing ratio (or mass flow rates) of the unit injector are perfectly balanced, the temperature distribution becomes highly uniform. A larger disparity in flow rate between the inner ring injector and the middle ring injector leads to a lower combustion efficiency. This effect differs from the effect of the mixing ratio difference between the two injector rings. Increasing the mixing ratio in the inner-ring injectors (or decreasing the mixing ratio in the middle-ring injectors) initially leads to a rise in combustion efficiency, followed by a subsequent decline. The maximum combustion efficiency of 89.10% is achieved when the mixing ratio is set to Km-1 = 0.7 and Km-2 = 2.79, respectively. Increasing the flow rate in the inner-ring injectors (or decreasing the flow rate in the middle-ring injectors) initially leads to an improvement in combustion efficiency, followed by a subsequent reduction. The maximum combustion efficiency of 86.13% is achieved when the mass flow rate is set to m-1 = m-2 = 0.1 kg/s. [ABSTRACT FROM AUTHOR]

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The rocket ejector refers to a core component of a rocket-based combined cycle (RBCC) engine. The ignition is of critical significance for rocket ejection. Reliable and stable ignition crucially determines the normal operation of the engine. In this paper, a thrust chamber with coaxial swirl injector for the RBCC rocket ejection was developed and tested. Gas oxygen (GOX) and kerosene acted as propellants. As revealed from the test results, the process of ignition pressurizing comprised four phases. The oxygen prefilling time before ignition slightly impacted the ignition time, whereas it affected the peak pressure of ignition. In a confined range, the peak pressure decreased as the prefilling time was extended. The ignition was simulated by building a numerical model, and the results well complied with the experimentally achieved results. The numerical model is capable of specifically indicating the position of the kernel of fire and the process of flame propagation. The simulation results reveal that the propellant could form a combustible condition within 4 ms. The kernel was 6 mm away from the injector, located at the oxygen and kerosene mixing interface and approaching the upper wall. The above results reflected the vital role of the central recirculation zone formed by the prefilled oxygen. The ignition energy was transported near the injector under the convection effect, which ignited the stoichiometric mixture, and the entire ignition could reach a stable state within 20 ms. The numerical model which was developed in this paper can help clarify the combustion mechanism. [ABSTRACT FROM AUTHOR]

A future nuclear fusion plant DEMO needs neutral beam injection (NBI) systems requiring a vacuum pumping system with a very high pumping speed, in the order of several 1000 m3/s. Large customized cryopumps are actually used to meet the requirements. A promising concept for future NBI systems is based on high capacity getter materials. The ZAO® alloy, developed by SAES Getters, Italy, provides a drastically improved performance for the pumping of hydrogen compared to conventional getter materials. This paper describes the experimental characterization of a large pump of scalable size with 15 kg of ZAO® and the achieved results, in particular the systematic investigation of sorption characteristics and regeneration behaviors. Major findings include a very good repeatability of the sorption performance, a reduced pumping speed at higher pressures only above the NBI relevant level, an improved performance (+20%) with elevated getter temperature and an isotope independent sticking coefficient for hydrogen. Furthermore, improved operation experience and regeneration prediction tools have been developed. Employing the experimental results, a simulation task was performed and the sticking factor of the getter cartridge was determined with 7%. [ABSTRACT FROM AUTHOR]

Attention to the method of removing large space debris objects by impacting them with an ion beam has not waned over the past 10 years. The application of this method to the space debris removal from the protected area of the Geostationary Earth Orbit (GEO) seems to be the most effective. This is due to a low energy consumption for removing an object to a safe orbit with ΔV≃11 m/s, which allows the removal of several objects by a single spacecraft. A service spacecraft can be developed for this purpose based on the TelSat geostationary communication satellite technology. At the same time, one of the problematic issues remains that is the development of an injector of a weakly divergent ion beam. The ion beam divergence during injection into the vacuum occurs under the insuperable influence of the ambipolar electric field acting in the beam volume. At the same time, the beam behavior depends on the initial divergence angle stipulated by the conditions of beam formation by the electrostatic acceleration system. This paper considers the results of calculated and experimental studies for the peculiarities of the formation of an ion beam in an ion extraction system with slit and round apertures. The dependence of the initial divergence half-angle on the beam perveance for both geometries was defined. In the operation of the injector designed for the space debris removal, it is necessary to ensure stability of the geometry of the ion-extraction system, which is subject to uneven thermal loading. The resulting thermomechanical deformations of the grids in the technology of ion thrusters are parried by giving the grids a plate shape. Therefore, flat grids made of a carbon-carbon composite material of a new type were used in experiments, which avoided noticeable deformations. The results of experimental investigation of the prototype of ion injector with two configurations of carbon grids (with round and slit perforation) and with the initial divergence half-angle of 2°-4° are given in this paper. The thrust control of an ion beam by changing of the screen grid potential under the condition of a constant beam perveance is considered. It is shown that such regulation is associated with a change in the Mach number, which affects the beam divergence. As an example, the calculation of the dependence of the coefficient k on the distance to the removing object is given, which is considered to be a spent satellite SUPERBIRD-A. • The minimum angle of the ion beam divergence of the ion injector were achieved. • A comparison of ion injector with slit-type and round-type aperture perforation. • The value of coefficient of thrust transfer to the object to be removed. [ABSTRACT FROM AUTHOR]

This paper presents the results of research on laser lap welding technology of heterogeneous materials and a laser post-heat treatment method to enhance welding performance. The purpose of this study is to reveal the welding principle of austenitic/martensitic dissimilar stainless-steel materials (3030Cu/440C-Nb) and to further obtain welded joints with good mechanical and sealing properties. A natural-gas injector valve is taken as the study case where its valve pipe (303Cu) and valve seat (440C-Nb) are welded. Experiments and numerical simulations were conducted where the welded joints' temperature and stress fields, microstructure, element distribution, and microhardness were studied. The results showed that the residual equivalent stresses and uneven fusion zone tend to concentrate at the joint of two materials within the welded joint. The hardness of the 303Cu side (181.8 HV) is less than the 440C-Nb side (266 HV) in the center of the welded joint. The laser post-heat treatment can reduce the residual equivalent stress in the welded joint and improve the mechanical and sealing properties. The results of the press-off force test and the helium leakage test showed that the press-off force increased from 9640 N to 10,046 N and the helium leakage rate decreased from 3.34 × 10−4 to 3.96 × 10−6. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For the short-term use of diesel engines, biodiesel can provide a comparable engine performance to that of using fossil diesel fuel. However, some arising problems including the reduction of the engine performance, the increase in lacquer deposits, and excessive carbon blacks in the combustion chamber and in the injectors resulting in an increase in the emissions and the damage to the engine have been indicated. Deposits formed inside or outside the injector may have an adverse influence on the engine performance and the fuel injection system. In this study, a review of the formed deposits in the injector of diesel engines fueled with biodiesel was conducted. The physicochemical mechanism of the deposit formation in the injector including injector nozzles, injector holes, and injector tips was mentioned. Moreover, the test-cycles for determining the deposit formation level in the injector were also introduced. Especially, the effects of the key factors such as biodiesel components, temperature, and injector configurations on the formation level of deposits were reviewed, and the utilization of the cativation mechanism in the controlling strategy of the deposits was presented. Besides, the impacts of deposits in the injector on the spray characteristics, combustion, and diesel engine operation process were also referred. [ABSTRACT FROM AUTHOR]

In the Ultra-High Efficiency Gas Turbine Engine, UHEGT (introduced in our previous studies) the combustion process is no longer contained in isolation between the compressor and turbine, rather distributed within the axial gaps before each stator row. This technology substantially increases the thermal efficiency of the engine cycle to above 45%, increases power output, and reduces turbine inlet temperature. Since the combustion process is brought into the turbine stages in UHEGT, the stator blades are exposed to high-temperature gases and can be overheated. To address this issue and reduce the temperature on the stator blade surface, two different approaches are investigated in this paper. The first is indexing (clocking) of the fuel injectors (cylindrical tubes extended from hub to shroud), in which the positions of the injectors are adjusted relative to each other and the stator blades. The second is film cooling, in which cooling holes are placed on the blade surface to bring down the temperature via coolant injection. Four configurations are designed and studied via computational fluid dynamics (CFD) to evaluate the effectiveness of the two approaches. Stator blade surface temperature (as the main objective function) along with other performance parameters such as temperature non-uniformity at rotor inlet, total pressure loss over the injectors, and total power production by rotor are evaluated for all configurations. The results show that indexing presents the most promising approach in reducing the stator blade surface temperature while producing the least amount of total pressure loss. [ABSTRACT FROM AUTHOR]

In this paper, a predictor‐based continuous‐discrete nonlinear observer is proposed for a class of nonaffine Lipschitz nonlinear systems with aperiodic sampled delayed output measurements and external disturbance. Firstly, this study introduces a class of delayed sampling hybrid nonlinear systems. By employing Lyapunov techniques and trajectory‐based stability theory, sufficient conditions are established for ensuring input‐to‐state stability of the delayed sampling hybrid nonlinear system with respect to external disturbances. Then the predictor‐based continuous‐discrete nonlinear observer is designed which consists of a continuous‐time observer, a compensating injector and a predictor. The continuous‐time observer is utilized to obtain continuous and delay‐free state estimation. The compensating injector is designed to compensate for output errors that occur between sampling instants. Furthermore, the predictor is employed to obtain delay‐free output error information, which is then utilized by the continuous‐time observer for feedback correction. The proposed observer's exponential input‐to‐state property against the disturbance is proved via the proposed hybrid system stability theory. The effectiveness of the proposed observers has been demonstrated through numerical simulations and performance comparisons with the zero‐order holder‐based observer and the output predictor‐based observer designs in order to highlight the effectiveness and advantages of the proposed observer. [ABSTRACT FROM AUTHOR]

In order to shorten the deflagration-to-detonation transition (DDT) distance of the pulse detonation combustion chamber, an experimental study of the effect of pneumatic atomization injector modification on atomization particle size amd gas-liquid two-phase U-bend pulse detonation combustion (U-PDC) chamber was carried out. Gasoline and air were used as fuel and oxidizer, and the atomization particle size was tested and the detonation characteristics of the U-PDC were obtained using the pneumatic atomization injector before and after the modification. The results show that the atomization size range of the injector before the modification is 111.6~152.9 µm, after the modification of the injector atomization size range of 76.4~107.2 µm, atomization size than before the modification is significantly reduced. The U-PDC using the injector before and after the modification can achieve stable operation in the range of 10~30 Hz, and the DDT distance shortened with the increase in frequency. At an operating frequency of 30 Hz, the DDT distance of U-PDC with the injector before modification is about 676 mm, and the DDT distance of U-PDC with injector after modification is shortened by 8.9% to about 616 mm. In addition, under the same operating conditions, due to the better atomization effect of the injector after modification, The fuel flow rate of U-PDC with the injector after modification is 5~10% smaller than that with the injector before modification when the average detonation pressure reaches its maximum value during the adjustment of fuel-flow. [ABSTRACT FROM AUTHOR]

This paper discusses a case study on the enhanced geothermal system (EGS), which entails a hydraulic stimulation at Patuha geothermal field, West Java, Indonesia. Patuha field is a volcano-hosted vapor-dominated geothermal system. A hydraulic stimulation was designed with 6,360 m3 (=40,000 barrels) of water injection to evaluate the enhancement in steam production. The water injection was conducted in three phases: a step-up period, a plateau period with a constant rate, and a step-down period, which raised the bottom hole pressure effectively and positively influenced formation. In addition, in EGS, rapid restorations of pressure and temperature to their pretest values near the bottom hole were observed, unlike in a typical nonvolcanic system. Hall plots, i.e., the Hall integral and Hall derivative, confirmed that the geothermal reservoir was stimulated, and thus, the hydraulic stimulation increased the steam production up to 11.4% at other production wells that were located near the cold-water injector. [ABSTRACT FROM AUTHOR]

High‐pressure hydrogen direct injection technology can enable an internal combustion engine to attain high thermal efficiency and discharge clean emissions; hence, the advantages provided by hydrogen jet impingement are crucial. This paper presents an experimental investigation of the high‐pressure hydrogen direct injection from a single‐hole cylindrical injector. A test rig with a spring set was designed based on the impulse conservation law to test important high‐pressure hydrogen jet impingement parameters, such as jet impingement force and impulse. The results show that the hydrogen gas jet exhibits a two‐zone behavior. In Zone I (near‐field dynamic region), the jet impulse is not conservative, and the jet characteristic parameters (jet impingement force and impulse) fluctuate—first decreasing and then increasing. In Zone II, the jet impulse is conservative. This two‐zone jet feature is induced by shockwaves because a high‐pressure hydrogen jet with a high nozzle pressure ratio reaches its sonic speed at the nozzle outlet. The Mach disk height is the inflection point of these two zones. Moreover, the hydrogen injection pressure has a considerable influence on the gas jet. As the injection pressure increases, the hydrogen jet impingement force and impulse increase. Both jet parameters have a linearly increasing relationship with injection pressure. [ABSTRACT FROM AUTHOR]

In the ITER neutral beam injectors (NBI), the presence of an external variable magnetic field generated by the ITER tokamak itself, could deflect the ion beam during acceleration and cause a loss of beam focusing. For this reason, the ion source, the accelerator and the neutralizer will be shielded from external magnetic field by means of a passive magnetic shield and a system of active correction and compensation coils (ACCC). The ACCC will operate in a feedback control loop and thus require the measurement of magnetic field inside the NBI vessel. Magnetic sensors for this application must be capable of measuring DC and slow variable magnetic fields, and be vacuum-compatible, radiation-hard and robust, since they will be subjected to neutron flux produced by fusion reactions in the tokamak and inaccessible for maintenance. This paper describes the realization and tests of fluxgate magnetic sensors prototypes specifically designed for this purpose before the installation in MITICA and ITER. [ABSTRACT FROM AUTHOR]

Modern internal combustion engines are designed to meet new emission standards and reduce fuel consumption. The wide application of direct fuel injection is associated with the problem of injector contamination. It leads to a deterioration of the engine's environmental performance. The paper aims to evaluate the effect of applying gasoline–butanol blends and appropriate additives on the formation of injector deposits. The research involved testing the engine on a dynamometer, evaluating the injector tips visually at 1000× magnification, and registering the fuel spray using high-speed imaging techniques with a laser and halogen lighting source. The effect of engine operating with the reference fuel was to coke the injector tip with a linear pattern. It increased the linear injection time to keep the engine's operating point constant over the 48 h test. The application of 20% (v/v) butanol reduced deposit formation. The best scavenging results were obtained by extending the engine operating time by the next 24 h and using a cleaning procedure. The procedure included a cleaning additive in addition to butanol. Among the cases analyzed, a combination of butanol and DCA (Deposit Control Additive) was the best method for injector patency restoration. [ABSTRACT FROM AUTHOR]

Common rail injector response characteristics depend on the control chamber pressure change rate, the outlet throttle diameter by manufacturing errors, or wear-induced deviations that affect the rate of pressure change in the control chamber, so the accuracy of the outlet throttle diameter directly affects the control valve response consistency. This paper presents a computational fluid dynamics (CFD) simulation of the effect of the deviation of the outlet throttle diameter on the average mass flow rate of the outlet throttle during the opening of the spherical valve in order to reduce this difference and ensure uniform injection characteristics. The results illustrate that with the increase in outlet throttle diameter deviation, the volume of gas phase in the control valve increases and the rate of pressure reduction in the control chamber accelerates, and the sensitivity coefficient of the average mass flow rate of the outlet throttle to the outlet throttle diameter deviation remains unchanged at 24.77. Cavitation occurs in the area of the outlet throttle when the spherical valve lift is 0.045 mm. The increase in rail pressure not only leads to an increase in the low-pressure area on the inner wall of the outlet throttle, an increase in the volume share of the gas phase, and an increase in the hydraulic impact on the sealing wall but also makes the average mass flow rate of the outlet throttle and the rate of change of the control chamber pressure during the opening of the spherical valve more sensitive to the deviation of the outlet throttle diameter. [ABSTRACT FROM AUTHOR]