Injection System Research Articles

A New Generation of Hydrogen-Fueled Hybrid Propulsion Systems for the Urban Mobility of the Future

The H2-ICE project aims at developing, through numerical simulation, a new generation of hybrid powertrains featuring a hydrogen-fueled Internal Combustion Engine (ICE) suitable for 12 m urban buses in order to provide a reliable and cost-effective solution for the abatement of both CO2 and criteria pollutant emissions. The full exploitation of the potential of such a traction system requires a substantial enhancement of the state of the art since several issues have to be addressed. In particular, the choice of a more suitable fuel injection system and the control of the combustion process are extremely challenging. Firstly, a high-fidelity 3D-CFD model will be exploited to analyze the in-cylinder H2 fuel injection through supersonic flows. Then, after the optimization of the injection and combustion process, a 1D model of the whole engine system will be built and calibrated, allowing the identification of a “sweet spot” in the ultra-lean combustion region, characterized by extremely low NOx emissions and, at the same time, high combustion efficiencies. Moreover, to further enhance the engine efficiency well above 40%, different Waste Heat Recovery (WHR) systems will be carefully scrutinized, including both Organic Rankine Cycle (ORC)-based recovery units as well as electric turbo-compounding. A Selective Catalytic Reduction (SCR) aftertreatment system will be developed to further reduce NOx emissions to near-zero levels. Finally, a dedicated torque-based control strategy for the ICE coupled with the Energy Management Systems (EMSs) of the hybrid powertrain, both optimized by exploiting Vehicle-To-Everything (V2X) connection, allows targeting H2 consumption of 0.1 kg/km. Technologies developed in the H2-ICE project will enhance the know-how necessary to design and build engines and aftertreatment systems for the efficient exploitation of H2 as a fuel, as well as for their integration into hybrid powertrains.

Ion flux measurements using a Mach-Langmuir probe in the ITER prototype neutral beam injection ion source

Neutral beam injection systems as foreseen for ITER use radio-frequency (RF) ion sources at low pressure, where negative hydrogen ions are mainly produced via surface conversion of neutral atoms and positive ions at a plasma facing grid (PG). Up to now there is only limited knowledge about how fluxes and directed velocities of the positive ions are affected by external parameters such as power, pressure and the horizontal magnetic filter field which causes plasma drifts and vertical asymmetries in the vicinity of the PG. For this reason a combined Mach-Langmuir-probe diagnostic is used at multiple positions in the expansion and close to the extraction system in the prototype RF ion source (1/8 of the full ITER ion source size) to measure the positive ions directed velocity and flux as well as the plasma parameters simultaneously. With increasing RF power the flux towards the PG is found to increase linearly, its magnitude being controlled by the plasma density. Towards ITER-relevant pressures the ion flux decreases, in contrast to the directed velocity, which increases non-linearly, reaching around 5 km s−1 at a pressure of 0.3 Pa. The magnetic filter field is discovered to strongly bent down the ion flow in front of the PG. As a result, the ions at the lower half of the PG flow almost exclusively parallel to it, wherefore the flux which impinges onto the lower PG half is reduced by around one order of magnitude.

Nanocrystals loaded collagen/alginate-based injectable hydrogels: A promising biomaterial for bioavailability improvement of hydrophobic drugs

The study aims to improve the solubility of poorly soluble drug by developing an optimized formulation of nanocrystals and extend its release profile by incorporating optimized nanocrystals in a biopolymer based injectable hydrogel. Nanocrystals of Silymarin (SM) were developed by anti-solvent precipitation technique followed by homogenization. Various stabilizers were investigated and combination of polyvinyl pyrrolidine K30 (PVP K30) and sodium lauryl sulfate (SLS) in a specific ratio was chosen as a stabilizer for nanocrystals. The optimized nanocrystals possessed mean particle size 172 ± 5.23 nm and PDI of 0.228 ± 0.02. Sodium alginate (Alg) and collagen (Col) based injectable hydrogel in combination with pluronic F127 showed good biocompatibility, mechanical strength and biodegradability. The developed formulation was characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infra-red spectroscopy (FT-IR) and X-ray diffraction (XRD) analysis. The results of FT-IR and TGA showed structural cross-linking between polymers and promising thermal stability of formulation with increasing temperature, respectively. The nanocrystals loaded Alg-Col-F127 injectable hydrogel was degraded completely in 48 h. The results of in vitro release studies and in vivo pharmacokinetic profiling of silymarin nanocrystals laden Alg-Col-F127 injectable hydrogel exhibited controlled release behavior as compared to coarse silymarin suspension and silymarin nanocrystals. Therefore, nanosuspension integrated biopolymer-based hybrid injectable hydrogel system may be used to assist solubility and bioavailability enhancement as well as serve as platform to provide controlled drug release.

A Simple Flow Injection System for Amperometric Detection of Ascorbic Acid Using Carbon Paste/Copper Schiff Base Composite Electrode

AbstractIn this paper, a simple, sensitive, and precise flow injection system was optimized and applied to ascorbic acid determination with a carbon paste electrode modified with the Schiff base copper complex. The modified sensor showed increased sensitivity toward ascorbic acid oxidation with a decrease of oxidation potential by 200 mV. Under optimized flow parameters, working potential, gasket thickness, sample and reaction coil volumes, and flow rate, the developed flow system gave a linear response from 5 to 75 μmol/L of ascorbic acid. The calculated limit of detection was 4.5 μmol/L, calculated as 3σ/s which corresponds to the absolute value of 40 ng for the 50 μL sample coil. The precision for six consecutive injections of 5 and 75 μmol/L ascorbic acid solutions was determined as a relative standard deviation of 5.8 % and 1.5 %, respectively. The flow injection system enabled up to 120 analyses per hour. An optimized flow system was applied to the determination of ascorbic acid in dietary supplements, after simple preparation.

Development of a CNN-based fault detection system for a real water injection centrifugal pump

Large-sized centrifugal pumps play a major role in produced water injection systems in oil and gas production. Monitoring this equipment operation is vital to guarantee its efficiency and to reduce the occurrence of unplanned downtimes. The main goal of this work was to develop a fault detection system based on artificial intelligence (AI) algorithms for a water injection centrifugal pump located at an oil and gas company’s offshore platform. The convolutional neural network (CNN) was the main algorithm investigated in this work. However, other machine learning techniques (i.e., support vector machines, random forest, and multilayer perceptrons) were used to compare against the results achieved by the CNN. A data-driven methodology was proposed for the stages of exploratory data analysis (EDA), data labeling, automatic hyperparameter optimization, training and testing of the chosen models. The results showed that the proposed methodology was effective and applicable. The CNN and the support vector machine (SVM) models presented interesting performances. The CNN model returned 93.7% precision and 59.8% recall, whereas the SVM model returned 84.6% precision and 66.7% recall. The challenges related to the use of a real dataset were also discussed, emphasizing the data labeling step. Applying the k-means clustering technique proved to be useful for labeling the data instances.

Injectable Thermoresponsive Microparticle/Hydrogel System with Superparamagnetic Nanoparticles for Drug Release and Magnetic Hyperthermia Applications.

Cancer is a disease that continues to greatly impact our society. Developing new and more personalized treatment options is crucial to decreasing the cancer burden. In this study, we combined magnetic polysaccharide microparticles with a Pluronic thermoresponsive hydrogel to develop a multifunctional, injectable drug delivery system (DDS) for magnetic hyperthermia applications. Gellan gum and alginate microparticles were loaded with superparamagnetic iron oxide nanoparticles (SPIONs) with and without coating. The magnetic microparticles' registered temperature increases up to 4 °C upon the application of an alternating magnetic field. These magnetic microparticles were mixed with drug-loaded microparticles, and, subsequently, this mixture was embedded within a Pluronic thermoresponsive hydrogel that is capable of being in the gel state at 37 °C. The proposed DDS was capable of slowly releasing methylene blue, used as a model drug, for up to 9 days. The developed hydrogel/microparticle system had a smaller rate of drug release compared with microparticles alone. This system proved to be a potential thermoresponsive DDS suitable for magnetic hyperthermia applications, thus enabling a synergistic treatment for cancer.

Flow analysis of a control ball valve in a common rail fuel injector

The electronic control common rail fuel injection system is one of the key technologies being used in modern diesel engines to improve the engine performance. A numerical simulation was conducted to study the characteristics of the fuel flow around the ball valve in the common rail fuel injector. The lift of the control ball valve and static pressure of the flow field around the control ball valve were measured respectively. The simulation was performed with the measurements as boundary conditions such that the flow characteristics can be correlated with the valve lift and the pressure upstream of the ball valve. Simulation results showed that during the valve opening and closing, a high pressure area appeared below the ball valve, while cavitation appeared in the area around the control ball valve. Specifically, the cavitation mainly appeared around the sealing circle, and its upstream area and the conical surface from the entrance to a certain distance downstream. The flow throttling happened at the outlet orifice under the steady-state condition when the valve was at the maximum opening position. The cavitation around the control ball valve was more serious under higher rail pressure conditions. The formation and development of the cavitation was found to be depending on the lift position of the ball valve and pressure of the flow around the ball valve during the valve opening and valve closing. Higher value of void fraction appeared in the flow when the lift of the ball valve was at a larger opening position. It was found that cavitation around the ball valve will affect the consistency and stability of the fuel flow. And cavitation erosion found at the valve seat from a simplified durability test appeared to be close to the place where cavitation appeared from simulation. Therefore, it is suggested that simulation work can be used to examine if cavitation occurs in the flow path of the control ball valve inside the injector in design phase and make necessary changes on the design to prevent the cavitation and the resulting damages to the control ball valve in the injector.

Electrochemical Determination of Streptomycin on an Electrode Modified with a Composite of Graphene Oxide and Gold–Nickel Binary System

A procedure was suggested for voltammetric determination of streptomycin from the catalytic current on a glassy carbon electrode with a composite based on reduced graphene oxide and gold–nickel binary system. The working conditions of the electrode modification (volume of the graphene oxide and chitosan suspension, duration of the electrolytic reduction of immobilized graphene oxide and electrodeposition of the gold–nickel binary system) and the conditions for recording the catalytic current in the flow injection system were determined. The procedure for streptomycin determination in a flow, compared to the determination under stationary conditions, is more sensitive, reproducible, and rapid. The streptomycin detection limit was 0.45 nmol, and the productive capacity of the analysis was 60 samples per hour. The streptomycin determination procedure passed trials in analysis of cow milk.

Impact of medium-pressure direct injection in a spark-ignition engine fueled by hydrogen

In the automotive sector, hydrogen is being increasingly explored as an alternative fuel to replace conventional carbon-based fuels. Its combustion characteristics make it well-suited for adaptation to internal combustion engines. The wide flammability range of hydrogen allows for higher dilution conditions, resulting in enhanced combustion efficiency. When combined with lean combustion strategies, hydrogen significantly reduces environmental impact, virtually eliminating carbon dioxide and nitrogen oxide emissions while maintaining high thermal efficiency. This paper aims to assess the potential of using an outwardly opening poppet valve hydrogen direct injection (DI) system in a small engine for light-duty applications. To achieve this, a comparison of performance, emission levels, and combustion parameters is conducted on a single-cylinder spark-ignition (SI) research engine fueled by hydrogen, using both port fuel injection (PFI) and this new direct injection system. Two different engine loads are measured at multiple air dilution and injection timing conditions. The results demonstrate notable efficiency improvements, ranging from 0.6% to 1.1% when transitioning from PFI to DI. Accurate control of injection timing is essential for achieving optimal performance and low emissions. Delaying the start of injection results in a 7.6% reduction in compression work at low load and a 3.9% reduction at high load. This results in a 3.1-3.2% improvement in ISFC in both load conditions considered.

Impacts of Injection Parameters on the Mixture Formation and Performance of Two-Stroke Spark-Ignition Direct-Injection Aviation Kerosene Engine

Abstract Two-stroke spark-ignition engines play a significant role in the field of power sources of small and medium unmanned aerial vehicles. There is a certain transition from burning gasoline to aviation kerosene (or heavy oil) and from carburetor or inlet injection system to direct-injection fuel system. However, the performance of two-stroke spark-ignition direct-injection engines fueled with aviation kerosene was not very ideal under heavy loads. Generally, the mixture formation is very important for engine combustion and performance, while injection parameters have great effects on mixture formation. Thus, various injection parameters of a two-stroke direct-injection kerosene engine were examined here. The results showed too early or too late injection timing (tinj) would deteriorate the mixture formation, resulting in lower brake power and brake thermal efficiency. Here the most suitable tinj was 150 deg CA BTDC. Too high or too low injection pressure (pinj) caused fuel short circuit loss and poor mixture quality, so the optimum pinj was 10 MPa. Too large injector installation angle (β) easily results in fuel spray impingement, and too small β causes fuel short circuit loss. Therefore, the best β was concluded to be 30 deg in this paper.

S-induced Phase Change Forming In2 O3 /In2 S3 Heterostructure for Photoelectrochemical Glucose Sensor.

In the past several decades, Photoelectrochemical (PEC) sensing still remains a great challenge to design highly-efficient semiconductor photocatalysts via a facile method. It is of much importance to design and synthesize various novel nanostructured sensing materials for further improving the response performance. Herein, we present an In2 O3 /In2 S3 heterostructure obtained by combining microwave assisted hydrothermal method with S-induced phase change, whose energy band and electronic structure could be adjusted by changing the S content. Combining theoretical calculation and spectroscopic techniques, the introduction of sulfur was proved to produce multifunctional interfaces, inducing the change of phase, oxygen vacancies and band gap, which accelerates the separation of photoexcited carriers and reduces their recombination, improving the electronic injection efficiency around the interface of In2 O3 /In2 S3 . As anticipated, an enhanced glucose response performance with a photocurrent of 0.6 mA cm-2 , a linear range of 0.1-1 mM and a detection limit as low as 14.5 μM has been achieved based on the In2 O3 /In2 S3 heterostructure, which is significant superior over its pure In2 O3 and S-doped In2 O3 counterparts. This efficient interfacial strategy may open a new route to manipulate the electrical structure, and energy band structure regulation of sensing material to improve the performance of photoelectrodes for PEC.

Numerical investigation of the combustion regime in pilot-ignited high-pressure direct-injection low reactivity fuel combustion with the injection system of eccentric configuration

The pilot-ignited high-pressure direct-injection (HPDI) combustion with the eccentric configuration is a practical approach to achieve high thermal efficiency and clean combustion. However, the combustion process and combustion regime still remain unclear. In this study, the effects of two key parameters “offset” (distance between concentric and eccentric injectors) and “dwell” (interval between concentric and eccentric injection timing) on the combustion process, combustion regime, and the corresponding performance are numerically investigated systematically. Results show that the interaction between the flame kernels of pilot fuel and the plumes of main fuel determines the combustion mode of each main fuel plume, and thereby different combustion regimes in the pilot-ignited HPDI engine can be generated by controlling the offset and dwell. Specifically, under the concentric configuration or the eccentric configuration with very small offset and dwell, all the main fuel plumes are in the non-premixed mode, exhibiting a diffusion combustion (DC) regime. Under the eccentric configuration with medium offset and dwell, some of the main fuel plumes are in the non-premixed and the others in the partially premixed mode, exhibiting a special combustion regime, which is named the multi-mode co-existing combustion (MMCC) in this study. Under the eccentric configuration with large offset and dwell, all the main fuel plumes are in the partially premixed mode, exhibiting a partially premixed combustion (PPC) regime. Among the three combustion regimes, the diffusion combustion regime exhibits the lowest ISFC and unburned HC emission but high NOx and soot emissions. The ISFC of the partially premixed combustion regime is almost double that of the other two regimes which is far from being acceptable. The MMCC regime shows a better comprehensive performance: achieving much lower ringing intensity and soot emission with almost the same ISFC compared to the diffusion combustion regime. In summary, the pilot-ignited HPDI combustion with the eccentric configuration can potentially achieve high fuel economy with low emissions, under the premise of the ratio of non-premixed and partially premixed combustion modes in the MMCC regime is well controlled.

Evaluation of luciferase and prefusion-stabilized F protein from respiratory syncytial virus mRNA/LNPs in pre-clinical models using jet delivery compared to needle and syringe

Described here is the evaluation of a luciferase (luc) and respiratory syncytial virus (RSV) messenger RNA / lipid nanoparticle (mRNA/LNP) vaccine using a Needle-free Injection System, Tropis®, from PharmaJet® (Golden, Colorado USA). Needle-free jet delivery offers an alternative to needle/syringe. To perform this assessment, compatibility studies with Tropis were first performed with a luc mRNA/LNP and compared to needle/syringe. Although minor changes in particle size and encapsulation efficiency were observed when using Tropis on the benchtop, in vitro luciferase activity remained the same. Next, the luc mRNA/LNP was administered to rats intramuscularly using Tropis or needle/syringe and tracking of the injection and distribution was performed. Lastly, an mRNA encoding a prefusion-stabilized F protein from RSV was delivered intramuscularly using both Tropis and needle/syringe at 1 and 5 mcg mRNA. An equivalent IgG response was observed using both Tropis and needle/syringe. The cell mediated immune (CMI) response was also evaluated, and responses to RSV-F were detected from animals immunized with needle/syringe at all dose levels, and from the animals immunized with Tropis in the 5 and 25 ug groups. These results indicated that delivery of mRNA/LNPs with Tropis is a potential means of administration and an alternative to needle/syringe.

Thermal-Hydraulic comparative analysis of G-III + BWR and PWR passive safety features under Loss of coolant accident

As one of symbolic design features of Generation-III and III+ (G-III and G-III + ) nuclear reactors, the passive safety system has been implemented on majority of G-III and III + PWRs and BWRs. The passive safety systems in those reactors are designed differently yet adhere to identical fundamental principles. It would be interesting to examine the similarities and differences between the passive safety systems of G-III + PWR and BWR. System code simulations for Small Break and Large Break Loss of Coolant Accident for the Economic Simplified Boiling Water Reactor (ESBWR) and China’s advanced PWR had been conducted, respectively. The results showed that the passive safety systems of ESBWR and China’s Advanced PWR were comparable in design, and when dealing with the similar type of SBLOCA and LBLOCA, the passive safety components with the same functionality could all contribute to the core's cooling with stability and reliability, and the injection flow rate values were nearly equivalent. Separating the injection lines of ESBWR's safety systems guarantees that the action sequence could well remain stable. This design could prevent the injection flow rate and action sequence from being impacted by the interaction of safety injection systems. This work could serve as a reference for the design of subsequent new reactors, thereby contributing to the design of reactors with enhanced economics and safety.

Feasibility study of a Heavy Ion Beam Probe for the Thailand Tokamak-1

A Heavy Ion Beam Probe (HIBP) diagnostic system can offer non-disturbing, local measurement of plasma electric potential and various plasma parameters. This paper presents results of a feasibility study for implementing a HIBP system on the Thailand Tokamak-1 (TT-1). With successful plasma discharges achieved in early 2023, TT-1, is planed for upgrades and expansion of diagnostic capabilities to conduct experiments in high confinement modes. Sector K is designated for the installation of the HIBP diagnostic system, where primary beam ions are injected through the top port and secondary beam ions emerge from the horizontal port. The HIBP system consists of two main components: (1) the primary beam injection, and (2) the detection of the secondary beam. In the injection system, the incident direction of the primary beam into the plasma is controlled by two pairs of electrostatic sweepers. For the detection of the secondary beam, the electric field produced by electrostatic sweepers, each with a length of 0.25 m and inclined at 30 degrees, ensures that the secondary beam ions enter the energy analyzer entrance at the center with normal angles. Candidate ions, such as Cs+, Rb+, and K+, with varying energies, are evaluated for their suitability based on beam attenuation and plasma density conditions. Cesium ions are suitable at lower densities (n̄e≤1×1019 m−3), while Rb+ and K+ are preferable at higher plasma densities (n̄e≥1×1019 m−3). The analysis indicates that the ratio of the attenuation current is approximately in the range of 10−3 to 10−2. This study provides valuable insights for the integration of the HIBP diagnostic system into TT-1, enabling investigations of H-mode plasma physics phenomena.

Detailed Gaseous and Particulate Emissions of an Allison 250-C20B Turboshaft Engine

Abstract Aviation is known to be one of the most significant contributors to air pollutants. This includes gaseous emissions, like carbon dioxide (CO2) and nitrogen oxides (NOx), and also particulate matter (PM), especially in the form of soot. This study conducted emission measurements on an Allison 250-C20B turboshaft engine operating on Jet A-1 fuel with a focus on gaseous compounds (e.g., ozone precursors) and PM. The different engine loading points were chosen based on the percentage thrust ratios of the International Civil Aviation Organization LTO-Cycle. A standard FTIR/O2/FID system to measure general gaseous combustion compounds, e.g., CO2, carbon monoxide (CO), unburned hydrocarbons (UHC), and NOx. For the investigation of the volatile organic compounds (VOC), which are known to act as ozone precursors, a gas chromatograph was applied. Different measurement methods were used to characterize the PM emissions. For the particle size distribution (PSD), we used two types of electrical mobility analyzers and an aerodynamic aerosol classifier. All measurement systems yielded comparable PSD results, indicating reliable results. The particle measurement methods all show increasing aerosol diameter modes (electrical and aerodynamic) with increased engine loading. The aerosol diameter modes were shifting from 29 nm to 65 nm. The size and shape of different individual particles were evaluated with a scanning electron microscope. A correlation between the injection system and the particle formation was established. Gaseous turboshaft engine emissions show high CO and UHC values at Ground Idle level. NOx levels were the highest at Take-Off conditions. Acetylene and ethylene were the most significant contributors to ozone formation.

A Comprehensive Review on Carbon Dioxide Sequestration Methods

Capturing and storing CO2 (CCS) was once regarded as a significant, urgent, and necessary option for reducing the emissions of CO2 from coal and oil and gas industries and mitigating the serious impacts of CO2 on the atmosphere and the environment. This recognition came about as a result of extensive research conducted in the past. The CCS cycle comes to a close with the last phase of CO2 storage, which is accomplished primarily by the adsorption of CO2 in the ocean and injection of CO2 subsurface reservoir formation, in addition to the formation of limestone via the process of CO2 reactivity with reservoir formation minerals through injectivities. CCS is the last stage in the carbon capture and storage (CCS) cycle and is accomplished chiefly via oceanic and subterranean geological sequestration, as well as mineral carbonation. The injection of supercritical CO2 into geological formations disrupts the sub-surface’s existing physical and chemical conditions; changes can occur in the pore fluid pressure, temperature state, chemical reactivity, and stress distribution of the reservoir rock. This paper aims at advancing our current knowledge in CO2 injection and storage systems, particularly CO2 storage methods and the challenges encountered during the implementation of each method and analyses on how key uncertainties in CCS can be reduced. CCS sites are essentially unified systems; yet, given the scientific context, these storage systems are typically split during scientific investigations based on the physics and spatial scales involved. Separating the physics by using the chosen system as a boundary condition is a strategy that works effectively for a wide variety of physical applications. Unfortunately, the separation technique does not accurately capture the behaviour of the larger important system in the case of water and gas flow in porous media. This is due to the complexity of geological subsurface systems, which prevents the approach from being able to effectively capture the behaviour of the larger relevant system. This consequently gives rise to different CCS technology with different applications, costs and social and environmental impacts. The findings of this study can help improve the ability to select a suitable CCS application method and can further improve the efficiency of greenhouse gas emissions and their environmental impact, promoting the process sustainability and helping to tackle some of the most important issues that human being is currently accounting global climate change. Though this technology has already had large-scale development for the last decade, some issues and uncertainties are identified. Special attention was focused on the basic findings achieved in CO2 storage operational projects to date. The study has demonstrated that though a number of CCS technologies have been researched and implemented to date, choosing a suitable and acceptable CCS technology is still daunting in terms of its technological application, cost effectiveness and socio-environmental acceptance.

Impact of Preheating on Flame Stabilization and NOx Emissions From a Dual Swirl Hydrogen Injector

Abstract Flame stabilization, flame structure, and pollutant emissions are investigated experimentally on a swirled injection system operating with globally lean air/hydrogen mixtures at atmospheric conditions and moderate Reynolds numbers. This injector consists of two coaxial ducts with separate injection of hydrogen into a central channel and of air into an annular channel. Both streams are swirled. The resulting flames exhibit two stabilization modes. In one case, the flame takes an M-shape and is anchored to the hydrogen injector lips. In the second case, the flame is aerodynamically stabilized above the injector and takes a V-shape. Regions of existence of each stabilization mode are determined according to the operating conditions. For low air flow rates, the flame can be either anchored or lifted above the hydrogen injector lips depending on the path followed to reach the operating condition. At high air flow rates, the flame is always lifted regardless of the trajectory followed. The impact of air inlet temperature on these stabilization regimes is then evaluated from T= 300 K up to 770 K. Flame re-attachment is shown to be controlled by edge flame propagation and the impact of preheating is well reproduced by the model. Unburnt hydrogen and NOx emissions are finally evaluated. Unburnt hydrogen is only observed for global equivalence ratios below 0.4 and at ambient inlet temperature. NOx emissions decrease when the global equivalence ratio is reduced. Furthermore, at fixed global equivalence ratio, NOx emissions decrease as the thermal power increases, regardless of air preheating and the flame stabilization regime. At high power, NOx emissions reach an asymptotic value that is independent of the thermal power. The impact of flame shape, air preheating, and combustion chamber wall heat losses on NOx production is also evaluated. NOx emissions are shown to scale with the adiabatic flame temperature Tad at the global equivalence ratio and the residence time inside the combustor.

Development of Learning Videos Using YouTube Integrated Video Prezi Applications on Fuel Injection Systems in Vocational Schools

The development of information and communication technology has touched various aspects of life, one of which is the world of education. Education cannot be separated from the development of IT. The Prezi video application can be used to create interesting learning video media for students. This research is a Research and Development (RD) research through a 4D development model, which consists of 4 stages, namely: (a) Define, (b) Design, (c) Develop, and (d) Disseminate. This study aims to develop material on the basic competence of gasoline injection systems for class XI Automotive Light Vehicle Engine Maintenance. Subject Automotive Light Vehicle Engineering ( TKRO) expertise program at a state vocational high school in Serang City. This research is limited to the development of media, which is validated by media experts, material experts, and student response trials. This is due to the limited research time. Data analysis techniques were obtained for product feasibility with a Likert scale. From the results of the stages carried out through this method, it can be concluded that the material expert validation was obtained by 87% with the very feasible category and the average media expert validation was obtained by 90% with the very feasible category to be used as an alternative learning video media to make it easier for students to understand material about Electronic Fuel Injection (EFI) Gasoline Injection system. Based on product trials conducted by 30 students, 87% of results were obtained in the very good category, or students were very interested in the learning videos that the researchers made.

Numerical Analysis of Flame Shape Impact on the Performance of Fuel Staging in a Lean-Burn Aeronautical Burner

Abstract The BIMER combustor is a lab-scale burner investigating fuel staging techniques as a stabilization strategy for lean premixed prevaporized combustion for aeronautical applications. Two stages compose its injection system: the pilot and the multipoint stages. The staging factor is defined as the ratio of fuel mass flowrate injected through the pilot stage over the total one. As three flame shapes were found experimentally, Large-Eddy Simulations are performed in this study to assess the impact of the flame shape on the combustion regime and stability of the burner. Two operating conditions were explored experimentally (pilot-only and multipoint-dominated) to validate the simulations and compare the three flames. An additional multipoint-only condition is also investigated for the V flame. The combustion regimes (premixed and non-premixed) and noise signatures (as a function of fuel staging) were compared to check whether these flames could benefit from the staging strategy. The M and Tulip flame combustion regimes are little affected by fuel staging, remaining mostly premixed and non-premixed, respectively, regardless of fuel staging. In opposition, the V flame changes from being mostly non-premixed to completely premixed when the injection is changed from pilot-only to multipoint-only. For the same staging factor values, the V flame also emits less noise compared to the other two flame shapes. These results show that the V flame shape is the only one that allows this burner to benefit from an efficient fuel staging strategy.