Injector Performance Research Articles

Multi-objective optimization of an electrical injector in Urea-SCR system

Electrical injector is mainly used in non-air-assisted urea dosing systems to atomize and inject urea water solution. It consists of solenoid switch valve and injector. A good performance of the electrical injector can improve dosing precision of urea dosing system. To investigate dynamic characteristics of the electrical injector, an equivalent magnetic circuit model of the solenoid valve was established and magnetic field of the solenoid valve was also simulated using a three-dimensional finite element model. The results show that the calculation error of the two models is 6%, demonstrating that the equivalent magnetic circuit model can effectively predict the magnetic characteristics of the solenoid. Taking opening time, closing time, and coil area of the electrical injector as objective functions, a multi-objective optimization algorithm was used to optimize the design parameters of the electrical injector. Opening and closing processes of the optimized electrical injector under different pressures and driving voltages were measured through laser triangulation sensor. The experimental results showed that calculation results of the proposed theoretical model were close to the measurement results. The opening time of the optimized injector has been reduced by 11%, the response of the injector has significantly improved.

Commissioning of the tracer-encapsulated solid pellet (TESPEL) injection system for Wendelstein 7-X and first results for OP1.2b

Abstract A new tracer-encapsulated solid pellet (TESPEL) injection system was successfully commissioned for the stellarator fusion experiment Wendelstein 7-X (W7-X) during its OP1.2b operational campaign. TESPELs are polystyrene encapsulated solid pellets loaded with tracer impurities that have been employed in other stellarator devices for impurity transport studies. During the OP1.2b campaign approximately 140 pellet injections were performed with a successful delivery rate of 89%, thus this system has proven to be very reliable. Here, the experimental set-up and methodology are described first. In addition, it is outlined how, through the analysis of TESPEL time-of-flight signals and of the temporal evolution of line emissions originating from shell and tracer species as well as comparisons with ablation models, the radial localization of the deposited tracer is determined. This contribution also provides a general overview of the TESPEL injector performance during OP1.2b, discusses the global effects of TESPEL injections on W7-X plasmas and reports on first results in terms of a summary of TESPEL injections, plasma response to TESPELs, the post-deposition evolution of tracer spectral emission lines and soft x-ray emissions.

Reservoir numerical simulation method considering time-varying relative permeability during polymer flooding process

Abstract In response to the abnormal decline in liquid production capacity during the middle and later stages of chemical flooding in Chinese offshore oil fields, in-depth analysis was conducted using reservoir engineering, dynamic analysis, and reservoir simulation methods. Because of the viscoelasticity of polymer solution, the relative permeability curve of oil/water during polymer flooding is different from that during water flooding, including the minimum mobile water saturation and residual oil saturation. In this study, an interpolation coefficient ‘f’ related to polymer solution concentration was firstly proposed for simplicity. Then, reservoir numerical simulation with the self-developed simulator ‘SIMFAST’ were conducted to investigate the influence of the interpolation coefficient ‘f’ on the injector and producer performance and the applications in actual field production history matching. The results indicated that compared with the commercial simulators, the self-developed simulator with the interpolation factor could more reliably describe the characteristic of the injected polymer solution in controlling water cut rise, and more efficiently simplify the combination of parameters on relative permeability curves during polymer flooding in offshore oilfields. Finally, above reservoir simulation method considering the change of the relative permeability curves during chemical flooding, was successfully conducted in the production history matching in J oilfield in Bohai Bay China, in terms of oil rate & water cut parameters. The research results give an efficient method to investigate the fluid seepage behaviour variation and its influence on oil rate and water cut during polymer flooding in China offshore reservoirs, which offers very useful technical support for the accurate design of chemical flooding schemes.

Computational study of the coaxial air and fuel jet through a 3-lobe strut injector for efficient fuel mixing in a supersonic combustion chamber

In this article, comprehensive simulations of the compressible air stream inside the combustion chamber are done to disclose the mixing and circulation performance of the 3-lobe injector behind the strut. The computational approach is employed to visualize the jet flow with/without the inner air jet released at supersonic flow. The main focus is the importance of lobe shape nozzle on the fuel diffusion into the main stream behind the strut. The role of the shock waves and their contact with the fuel jet flow is also investigated in the present work. Free stream velocity inside the combustion chamber is Mach = 4 while the hydrogen fuel jet is injected via sonic speed. A comparison of single and 3-lobe nozzles indicates that the lobe configuration of the nozzle increases the circulation behind the nozzle. Besides, the usage of the internal air jet increases the contact of the fuel jet with the shear layer initiated from the edge of the strut.

Effects of slit geometric parameters on spray characteristics of double-slit pintle injectors

Pintle injectors have garnered significant research attention in recent years, particularly for their applicability in reusable launch vehicles, owing to their wide thrust control range and excellent combustion stability. While research has explored the characteristics of pintle injectors in the context of developing these components for actual engine applications, studies focusing on the effects of design parameters on injector performance have been limited. This study investigated the effects of slit geometric parameters, specifically the blockage factor (BF) and slit area ratio (γ), on the spray characteristics of double-slit pintle injectors. Cold-flow tests were conducted using planar pintle injectors with water and ethanol as simulants. The spray angle and Sauter mean diameter (SMD) were measured using the shadowgraph technique, and the distribution of mass flow rate and mixture ratio was analyzed using a mechanical patternator. The experimental results revealed that two distinct streams were injected at different angles from each row of slits, resulting in a division of spray shape, SMD, and mass flow distribution into three regions based on the two streams. These spray angles, termed primary and secondary spray angles, were quantified as functions of the local momentum ratio, determined by BF and γ. To correlate the spray characteristics with combustion performance, mixing quality and a representative droplet size metric, the integral Sauter mean diameter (ID32), were presented. The study found that higher values of BF and γ corresponded to improved mixing quality.

Experimental Study of High-Diodicity Inlet Effects On Rotating Detonation Combustor Performance and Operability

Abstract Implementing high-diodicity inlets is critical to reduce backflow and mitigate the pressure loss across the injector in RDCs. Experiments on air injection diodicity were conducted in a non-premixed RDC for both cold-flow and reacting conditions. The introduction of a Tesla-like diode impacted operating modes and injector dynamics, but the extent of that effect depended on the throat-to-combustor area ratio. A smaller ratio mitigated the impact of the diode on detonation characteristics, while a larger ratio extended the operating range of stronger wave modes. The diode stabilized RDC operation through an increased static pressure drop, but limited performance most likely due to poor reactant mixing and local equivalence ratio distribution. Cold-flow tests showed a higher diodicity for the diode, which may contribute to higher pressure gain in reacting experiments. A modified diodicity formulation based on reacting flow measurements was introduced, suggesting that a multi-metric approach can be useful to assess injector performance. High-diodicity air inlets could be useful tools for reducing total pressure loss and controlling operating modes, but careful consideration is required to limit adverse effects on processes like reactant mixing.

Effects of Valve, Armature, and Armature Pin Guidance on Diesel Injector Performance

The valve, armature, and armature pin are critical factors influencing the hydraulic pressure differences in diesel injectors, and are essential for injection and backflow quantity control. These components play crucial roles in enhancing energy efficiency and reducing engine emissions. This experimental study investigated the effects of clearance between the valve, armature, and armature pin guidance. Forty-nine 2000 bar common-rail injectors (Bosch) were tested in calibrated stations. Injection quantities were assessed at both minimum and maximum operational pressures. Backflow rates were specifically examined at maximum pressure. A correlation matrix was created using Python to analyze the relationship between inputs and outputs, identifying dominant characteristics that define injector behavior. Increased injector precision correlated with reduced fuel consumption and enhanced energy efficiency. The study found that the effect of clearance between the armature and armature pins was more significant than that between the valve and armature. Injection quantities were observed to increase with pressure, and no critical difference in injection quantities was noted among different diameter groups at the minimum pressure point. Backflow quantities were consistent within groups when the armature–armature pin and valve–armature clearances were minimized.

Surveillance Data Analysis Reveals Well Performance and Reservoir Connectivity: A Case Study in Alasehir Geothermal Field

SummaryThe integration of surveillance data analysis, encompassing wellbore pressure, fluid flow rate, tracer injection, and recovery, is pivotal in deciphering the dynamic behavior of wells within a geothermal field. This comprehensive study focuses on the interconnectivity between producers, gauged by the reciprocal-productivity index (RPI), and the synergy between producers and injectors, assessed through capacitance-resistance modeling (CRM). The modified-Hall analysis further corroborates the performance metrics of both injectors and producers, thereby reinforcing operational excellence. These methodologies and related analytical tools are instrumental in refining field management practices.Executing meticulous tracer tests and subsequent analyses is crucial in validating the CRM’s applicability in the field. The fusion of these investigative techniques solidifies the role of CRM in managing geothermal reservoirs. Additionally, this study sheds light on the potential compartmentalization within the reservoir and monitors the evolving performance of producers and injectors over time. Utilizing a suite of analytical tools, including RPI, CRM, and modified-Hall analysis, provides a holistic insight into the reservoir dynamics at the Alaşehir field in Türkiye, ensuring a sustainable and optimized exploitation of geothermal energy.

Performance evaluation of modified pintle-type fuel injector for LRE (liquid rocket engine)

This research focuses on the fluid dynamics analysis and empirical validation of a modified pintle-type fuel injector through computational modeling. The primary aim is to assess the injector's performance metrics, including spray dispersion and orientation, flow velocity, turbulence levels, and vortex formation, by adjusting the pintle's positioning, which inherently modulates the flow rate. The observed effects draw parallels with the interactions seen in conical spray and hollow cone swirl atomizers. A pintle-type fuel injector model was developed using geometric design software, and computational fluid dynamics simulations were conducted to ensure effective fuel and oxidizer blending. This study evaluates key performance indicators, such as thrust output and combustion efficiency, under specific operational pressures and velocities at the injector's orifice.

LHC Upgrades in preparation of Run 3

The Large Hadron Collider (LHC) Long Shutdown 2 (2019–2021), following LHC Run 2, was primarily dedicated to the upgrade of the LHC Injectors but it included also a significant amount of activities aimed at consolidation of the LHC machine components, removal of known limitations and initial upgrades in view of the High-Luminosity LHC (HL-LHC) to favour the intensity ramp-up during Run 3 (2022–2025). An overview of the major modifications to the accelerator and its systems is followed by a summary of the results of the superconducting magnet training campaign to increase the LHC operation energy beyond the maximum value of 6.5 TeV reached during Run 2. The LHC configuration and the scenarios for proton and ion operation for Run 3 are presented considering the expected performance of the upgraded LHC Injectors and the proton beam intensity limitations resulting from the heat load on the cryogenic system due to beam-induced electron cloud and impedance.

Recent advancements with the H− injector performance for the Spallation Neutron Source operation and upgrade

The Spallation Neutron Source (SNS) located at the Oak Ridge National Laboratory is an accelerator-based, pulsed neutron facility utilized for a broad range of scientific research and industrial applications. In the past 5 years, the facility has reliably been operated at its baseline design beam power of 1.4 MW, and it is currently undertaking an upgrade to double its power to 2.8 MW. A 65-keV H− injector, which comprises an rf-driven H− ion source and an electrostatic low energy beam transport, delivers the required high-current, time-structured H− beam to the accelerator. The H− injector can reliably provide 50-60 mA beam current at 6% duty-factor (1 ms, 60 Hz) for a 3-4 month service cycle. To ensure sufficient operational margins for the SNS routine operations and ongoing upgrade requirements, the injector system has been continuously improved on a R&D test stand. This paper presents the operational status and recent advancements with the injector system performance including the enhanced ion source beam output capability up to ∼110 mA, the improved ion source plasma ignition reliability using a 27.12-MHz RF system, and the upgraded LEBT beam chopper system etc.

Experimental Study of Spray and Combustion Characteristics in Gas-Centered Swirl Coaxial Injectors: Influence of Recess Ratio and Gas Swirl

The spray and combustion characteristics of a gas-centered swirl coaxial (GCSC) injector used in oxidizer-rich staged combustion cycle engines were analyzed. The study focused on varying the recess ratio, presence of gas swirl, and swirl direction to improve injector performance. The impact of the recess ratio was assessed by increasing it for gas jet-type injectors with varying momentum ratios. Gas-swirl effects were studied by comparing injectors with and without swirl against a baseline of a low recess ratio gas injection. In atmospheric pressure-spray experiments, injector performance was assessed using backlight photography, cross-sectional imaging with a structured laser illumination planar imaging technique (SLIPI), and droplet analysis using ParticleMaster. Increasing the recess ratio led to reduced spray angle and droplet size, and trends of gas swirl-type injectors were similar to those of high recess ratio gas jet-type injectors. Combustion tests involved fabricating combustion chamber heads equipped with identical injectors, varying only the injector type. Oxidizer-rich combustion gas, produced by a pre-burner, and kerosene served as propellants. Combustion characteristics, including characteristic velocity, combustion efficiency, and heat flux, were evaluated. Elevated recess ratios correlated with increased characteristic velocity and reduced differences in the momentum–flux ratios of injectors. However, increasing the recess ratio yielded diminishing returns on combustion efficiency enhancement beyond a certain threshold. Gas swirling did not augment characteristic velocity but notably influenced heat flux distribution. The trends observed in spray tests were related to combustion characteristics regarding heat flux and combustion efficiency. Additionally, it was possible to estimate changes in the location and shape of the flame according to the characteristics of the injector.

Effect of unloader valve spring tension on hydraulic performance of CRI1 electromagnetic injector

The report reflects the results of an experimental study of the influence of the tension of the unloading valve spring on the hydraulic characteristics of electromagnetic nozzles. The research was done on a CMX6000X universal diesel fuel system test bench. An electromagnetic nozzle of the first-generation Common Rail - BOSCH CRI1 was chosen as the object of the study. It was found that with an increase in the tension of the spring of the unloading valve in all test modes, a decrease in the amount of fuel per cycle was observed. The rate of change of the amount of fuel per cycle for the individual test modes is different in the individual parts of the size range of the adjusting shim. The optimal thickness of the adjusting shim for the spring tension of the unloading valve for the tested nozzle is from 1.60 mm to 1.70 mm.

The analytical and numerical study of alternative fuel injectors for the purpose of reducing chemical pollution in aviation sector

In this paper, both analytical and numerical analyses are conducted to study the behavior of a simplex time injector with a swirl chamber represented by a pin, designed to operate with kerosene. In an effort to reduce chemical pollution, the injector's performance when operating with alternative fuels such as biofuel and ethanol is investigated. Calculations have been performed to analyze the use of these three fuels at various pressures up to 100 bar. Analytical calculations were used to determine parameters such as spray angle, droplet size, fuel film thickness, and more. For a better visualization of the phenomena occurring during the injector's operation with these three fuels, numerical simulations were carried out using ANSYS, and the spray of droplets at various pressures at the injector inlet was presented. The study revealed that among the liquids studied, ethanol is the most optimal fuel. Ethanol has low viscosity and low density, making it easier to atomize by our injector compared to pure biofuel, which has higher density and viscosity values. The calculations demonstrated the qualities of ethanol following atomization, including a thin liquid film, a wide spray angle consisting of small-sized droplets, at any pressure difference, compared to the other studied fuels. It was observed that pressure difference has a significant impact on the atomization of a liquid. The best atomization qualities and optimal values were achieved when the pressure difference is high.

Uji Kinerja Sistem Fertigasi Tanaman Bawang Merah (Allium cepa L.)

The purpose of the fertigation system is to meet the needs for irrigation and fertilizer for plants provided simultaneously through the drip irrigation system. Appropriate application of fertilizer and irrigation (both quantity and time of application) is the key to the growing process of shallot plants. The aim of the research was to test the fertigation system, analyze the performance of the fertilizer injector, and determine the uniformity of the drops in the drip fertigation system. Fertigation with a drip irrigation system design using a dripper line emitter (Streamline X, 16 mm diameter) with a spacing of 30 cm, 1-2inch PVC type manifold pipes, 4inch main pipe PE type, and 2 - 3inch PE type sub-main pipe. The water distribution method used a pump with a discharge of 13 m³/hour, a fertilizer injector with an injector (dosing proportional mix-rite), and an automatic control box system using NMC Pro. The variables observed were coefficient of uniformity (CU), fertilizer injector performance, and wetting diameter on the soil surface. The results showed that the appropriate fertilizer injector size setting for plant growth in each shallot growth phase was 0.3, 0.4, and 0.5. The irrigation efficiency and CU value were 96 % and 86 % respectively, which means that the water distribution via dripper lines has good uniformity with an average wetting diameter of 22 cm. Keywords: Coefficient of Uniformity, Dripper Lines, Fertigation, Fertilizer Injectors, Shallots.

Simulation of ammonia injection system for a compression ignition engine

Ammonia in anhydrous and aqueous forms, are attractive carbonless fuels for future marine diesel engines. The aim of this study was to determine if these fuels could be injected into a two-stroke marine diesel engine using a unit injector system. In this study, existing in service injector hardware was used to develop a dynamic numerical injector model. The results of the simulation were then validated against injector performance literature obtained for an engine, using conventional diesel fuel oil. Using the developed numerical model, the injection performance of anhydrous and aqueous ammonia solutions could then be investigated. The study found good correspondence between the model and the pressure trace found in literature. In terms of fuel injection performances, it was found that both fuels were injectable with a unit injector, however the correct volume and mass required were not achieved. Furthermore, injection timing and duration were affected marginally. For aqueous ammonia, with the higher bulk modulus, injection was advanced by 0.21 CA degrees and for anhydrous ammonia with a lower bulk modulus; it was delayed by 0.21 CA degrees. Overall proper operation of the injection system was observed. This outcome is promising, especially in shifting the maritime industry towards zero carbon ammonia engines.

High-brightness electron injectors for high-duty cycle X-ray free electron lasers

The successful development in the last two decades of X-ray free electron lasers (FELs) with their revolutionary brightness performance has been tightly dependent on the parallel development of electron guns and injectors capable of providing the high-brightness electron beams required by FELs lasing at these short wavelengths. The ultimate brightness delivered by a linear accelerator (linac) is already set at its injector and the remaining part of the accelerator can be only designed to preserve the injector performance. The technology to be used for the accelerator part of an X-Ray FEL strongly depends on the duty-cycle at which the FEL operates. Normal-conducting, room-temperature, copper-based radio frequency (RF) technology is typically used for low duty-cycles of up to approximately 10−3. For higher duty-cycles and up to continuous wave (CW) operation, the linac must rely on superconductive RF technology because, with the higher duty-cycle, the increasingly higher power dissipated in normal conducting RF structures becomes excessive for the warm technology. The situation changes in the lower energy part of the accelerator, where injector schemes, based on direct current, normal-conducting, and superconducting RF electron guns, are demonstrating the beam quality performance required by high-duty-cycle X-ray FELs. In this paper we start with a description of the requirements for such injectors, followed by an overview of the pursued technologies and schemes, and by a discussion on the main differences in terms of beam dynamics between low and high duty-cycle injectors.

Fluid-solid coupling simulation study on fuel leakage and deformation characteristics of precision coupling component in common rail injector and influence of pressure equalizing structure

In the foreseeable future, the use of fossil energy is still irreplaceable, makes efficient use of fossil energy and reduce emissions became important topics. Diesel engines have a very high share in the transportation field, and high-pressure common rail system has highly improved the performance of diesel engines. As the most important component of common rail system, the performance of common rail injector directly affects the engine. Precision coupling components are composed of moving parts with very precise clearance fit in the injector. With the wear of parts, fuel leakage of precision coupling components may reach the same level as injection quantity, which will seriously affect the injection pressure actually established, and then affect the power, efficiency, and emission performance of diesel engine. Many researchers have studied fuel leakage of precision coupling components, and put forward different methods to reduce fuel leakage, including improving the machining accuracy and machining annular grooves on parts. However, the wear of parts makes it a high-cost and low-effective method to improve machining accuracy. Besides, researchers have not fully considered the deformation of parts. In this work, fluid-solid coupling simulations were performed to analyze deformation and static fuel leakage characteristics, and to investigate effects of pressure equalizing structure on deformation and leakage of precision coupling component in common-rail injector. Different from the previous researches, the influence of machining the annular groove on the plunger sleeve instead of on the plunger, and influence of coexistence of annular groove and deformation were considered. The results show the deformation characteristics of the parts, the fuel flow characteristics in the gap, and the influence of the annular groove on the fuel leakage. The connection between the deformation of parts and fuel leakage, and potential methods to reduce the leakage are also discussed.

Analysis of potential improvements in the performance of solenoid injectors in diesel engines

Efficient fuel injection and exhaust gas cleaning systems are needed to promote the development of high-performance internal combustion systems and decrease greenhouse gas emissions. Electronically controlled injection systems enable nearly unlimited control over system components whose operation is limited by the inertia of moving parts and other physical phenomena. In the present study, a novel technology for manufacturing magnetic cores was proposed to improve the performance of solenoid injectors in Diesel engines. The conducted simulations and experiments revealed that the developed technology can increase the speed of solenoid injectors. In the proposed solution, the fuel dose was split to effectively control the injection process and improve engine performance.

Effect of ambient pressure on the performance of a gas-centered swirl coaxial injector

In this study, water and air were used as simulated media to investigate the spray characteristics of a gas-centered swirl coaxial (GCSC) injector under different ambient pressures through experimental, simulation, and theoretical approaches. The results showed that for the same liquid mass flow rate, the breakup length of the liquid film decreased with increasing ambient pressure, with the extent of the decrease diminishing as the ambient pressure increased. In addition, it was found that under the same ambient pressure, the larger the liquid mass flow rate, the shorter the liquid film breakup length. Moreover, for any gas–liquid mass flow ratio (GLR), the spray angle increased significantly with ambient pressure, and the liquid film suddenly expanded compared to the no-ambient pressure condition. At the same time, the breakup length of the liquid film increased. As ambient pressure increased, the spray angle increased while the breakup length decreased. When the GLR was small, self-pulsation occurred, which gradually disappeared with increasing ambient pressure. The frequency of self-pulsation decreased with increasing ambient pressure. The periodic self-pulsation of the spray was the result of the combined effects of the centrifugal force of the rotating liquid film, surface tension of the liquid film, aerodynamic force, and pressure difference inside and outside the liquid film. Overall, these findings provide insight into the spray characteristics of GCSC injectors under different ambient pressures, which can be of importance to the design and optimization of liquid rocket engines.