bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of Preheating on Flame Stabilization and NOx Emissions From a Dual Swirl Hydrogen Injector
Authors: Magnes Hervé , Marragou Sylvain , Aniello Andrea , Selle Laurent , Poinsot Thierry , Schuller Thierry 
Published: September 2023

Abstract
Flame stabilization, 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. Finally, NOx emissions are shown to scale with the adiabatic flame temperature Tad at the global equivalence ratio and the global residence time inside the combustor.
Computational Modeling of Hydrogen and Hydrogen-Methane Fuel Combustors for Gas Turbine Engine Applications
Authors: Prasad Mathiyalagan Senthil , Khot Mahaveer , Subramanian Sundaresa “Mani” 
Published: September 2023

Abstract
Related to the Sustainable Aviation Programs, focused on technologies to achieve some ambitious decarbonization goals for aircraft engines, research and development efforts into using alternative fuels, such as Sustainable Aviation Fuel (SAF) and Hydrogen. In relation to these efforts, this proposed study will focus on using Hydrogen and Hydrogen fuel blends in aircraft engine combustor to study the impact of reducing CO2 and NOx levels at typical operating conditions. Along with other SAF, Hydrogen is one of the most promising fuels for the Aviation industry to reduce CO2 levels significantly. However, NOx emissions are a bigger challenge in a Hydrogen-Air combustion system. Understanding the NOx emissions and its levels along with the temperature distribution in the combustor becomes even more challenging with Hydrogen as the primary fuel. Numerical simulations of combustion, with appropriate representation of chemical kinetics is expected to provide more insights about the temperature distribution and NOx emissions, thus aiding better combustor designs. At the present time, limited computational studies are underway in the gas turbine community. In this paper, multiple computational fluid dynamics (CFD) analyses have been completed by varying the combinations of mass fraction of Hydrogen and Methane in the fuel mixture for a NASA published public domain gas turbine combustor geometry under two different fuel flow conditions. All the previous calculations were for non-reacting cases, primarily to study the fuel-air mixing characteristics. The Hydrogen percentage in the mixture was varied from 0 to 100% (all Methane to fully Hydrogen) in steps of 25%. In this particular study, reacting flow simulations were performed for a pure Hydrogen and 50% H2-50% CH4 mixture and are presented and discussed. Converge CFD software was utilized for all the reacting flow calculations using the referenced NASA combustor geometry under combustor inlet conditions at the design point. The numerical results are presented and discussed with the available experimental data for the combustion performance and emissions.
Physics Discovery of Engineering Applications With Constrained Optimization and Genetic Programming
Authors: Luan Lele , Jacobs Ryan , Ghosh Sayan , Wang Liping 
Published: September 2023

Abstract
Discovering physics from data have the potential to advance our understanding and prediction of a system where the governing physics are unknown but experimental data are available. Physics-based models are conventionally obtained from rigorous first principles derivations such as conservation laws or knowledge-based phenomenological derivations. However, inferring physics-based models remains challenging for many real-world complex systems with intertwined and coupled multi-physics that are challenging to derive from first principles. In recent years, data-driven physics discovery has become an attractive research topic across many scientific disciplines due to the increasing richness of observational data and advances in machine learning. Various data-driven physics discovery algorithms have been proposed to extract simple but appropriate models governing the systems from the observed data. Among the proposed algorithms, genetic programming (GP) based symbolic regression (SR) plays a dominant role. Here, we build a general GP based SR platform to discover physical models from observations for real-world systems. The platform is used to solve an optimization problem where the outcome is a set of human-readable equations that the user can select from based on accuracy vs parsimony trades. The discovery process also considers the prior knowledge of experts, which manifests as constraints to enhance the embedding of physics and avoid overfitting. The discovered models not only have high interpretability but also demonstrate good extrapolation performance.
Thermoacoustic Characterization of a Premixed Multi Jet Burner for Hydrogen and Natural Gas Combustion
Authors: Beuth Jan Paul , Reumschüssel Johann Moritz , von Saldern Jakob G. R. , Wassmer Dominik , Ćosić Bernhard , Paschereit Christian Oliver , Oberleithner Kilian 
Published: September 2023

Abstract
In this study, the acoustics and flame dynamics of a prototype multijet burner with 19 individual mixing tubes for operation with pure hydrogen and pure natural gas are experimentally investigated. The burner transfer matrix of the jet burner is determined from experimental data and acoustic network modeling, showing very good agreement. The burner plate and attached mixing tubes are shown to be well approximated with an acoustic model of a perforated plate with bias flow. Accordingly, the burner is found to feature a high level of acoustic damping. A comparison of the flame dynamics of the two fuels considering mass flow and equivalence ratio variation reveals that the flame transfer functions (FTFs) are dominated by a convective mechanism originating from the upstream end of the mixing tubes where the fuel is injected. Consequently, these are most likely fluctuations in the equivalence ratio that feature two characteristic time scales: the convection time in the mixing tubes and along the flame. The overall qualitative shape of the FTFs for hydrogen and natural gas at equal thermal power is found to be similar, with the dynamics of the natural gas flames being more responsive to acoustic excitation, as evident in generally higher gain values. Distinctly less pronounced phase decays are observed for hydrogen compared to natural gas operation. Moreover, the FTFs for H2 are found to change only slightly across the considered range of equivalence ratios. At the same time we observe only small changes in the corresponding static flame shapes. These observation are consistent with the hypothesis of a dominant convective mechanism. In conclusion, the study provides valuable information on the acoustics and flame dynamics of multijet burners for flexible fuel operation.
Characterization of a Novel AM Micromix Nozzle Burning Methane to Hydrogen
Authors: Durocher Antoine , Fan Luming , Francolini Benjamin , Füri Marc , Bourque Gilles , Bergthorson Jeffrey M. , Yun Sean , Vena Patrizio 
Published: September 2023

Abstract
As the energy landscape transitions to low/zero-carbon fuels, gas turbine manufacturers are targeting fuel flexible operation with natural gas, syngas, and hydrogen-enriched mixtures. Having a single geometry that can support the different fuel blends requested by clients can accelerate the transition to cleaner energy generation and mitigate the environmental impact of gas turbines. Toward this goal, micromix combustion technology has received significant interest, and when coupled with additive manufacturing, novel injector geometries with unique configurations may be capable of stabilizing premixed, partially-premixed, and diffusion flames using fuel mixtures ranging from pure methane to pure hydrogen. In this work, a preliminary investigation of this micromix concept is performed in the Atmospheric Combustion Rig at the National Research Council Canada. Flame stability maps are obtained for fuel lean mixtures of H2/CH4 ranging from 0/100, 70/30, 90/10, to 100/0%, by volume. Multiple flame shapes are observed depending on the fuel mixture and combustion mode selected. PIV, OH and acetone planar laser-induced fluorescence (PLIF), and acoustic measurements provide additional insights into the combustion process of these novel burners to better understand the stability mechanisms. The quality of the fuel-air mixing from the premixed and micromix injectors is assessed using acetone as a tracer for the fuel, while simultaneous OH-PLIF measurements provide an indication of the post-flame regions in the flow. Acoustic measurements complete the current dataset and provide combustion dynamics maps measuring the normalized pressure amplitudes and identifying the dominant frequencies. The preliminary characterization of this AM micromix nozzle shows promising fuel flexibility with wide stability margins and low combustion dynamics for this single nozzle burner.
Sensor System Maturation for Gas Turbine Engine Particulate Ingestion Monitoring
Authors: Papadopoulos George , Bivolaru Daniel , Siu Spencer 
Published: September 2023

Abstract
Experimental studies of turbine engine sand, dust, and ash ingestion have shown that certain constituents, typically such as Calcium, Magnesium, Aluminum, and Silicon (CMAS) compound minerals and/or Chlorides and Sulfates, are particularly detrimental to engine turbine components. These reactive media undergo a phase change from solid to semi-solid as they pass through the combustion section of the engine under certain conditions characterized by size and mass. The phase change allows them to adhere to various turbine components including but not limited to stator vanes, rotor blades and shrouds. Unfortunately, with no on-board sensing technology the only warning signs that the flight crew has to an impeding airborne particle ingestion problem are lagging indicators, such as the St. Elmo’s Fire effect seen at night when charged ash particles hit the aircraft or a sulphurous smell and dust within the cabin. Hence, a sensor system that can measure the composition, size and concentration of particles being ingested by a gas turbine while in flight can provide pilots the warning they need to limit damage by either exiting the area or taking other actions to avoid prolonged exposure that can lead to serious damage mechanisms, both in the military where operational limits are always pushed to the extreme, and in the commercial area where safety is paramount. The current paper reports on the maturation of an in-situ, advanced monitoring and measurement of sand (AMMoS) sensor system that can be integrated at several places within an engine (e.g. aircraft inlet, engine inlet, engine bypass, engine gas path) with minimum modifications. The AMMoS system can provide measurements of composition, size and concentration for particles ingested by the engine. The current paper describes maturation efforts involving AMMoS system validation for particle size and system operation under various particle loading conditions. A dedicated test apparatus was assembled to facilitate the use of image-based diagnostics for providing independent measurements on the particle laden flow environment.
Biocompatibility and Mechanical Behaviour Studies on Wire-Arc Additive Manufactured Stainless Steel 316L and Shape Memory Alloy (NiTi) Materials for Biomedical Implants
Authors: T. Geethapriyan , Badhai Jhasketan , Karthik Sibi , Sonawane Avinash , Palani I. A. 
Published: September 2023

Abstract
Stainless steel 316L (SS316L) and Nickel-titanium alloy (NiTi), which are additively manufactured metallic biomaterials, are explore for their biocompatibility and mechanical properties in bio-implant applications. The nickel-titanium alloy (NiTi) has been suggested for exceptional thermal shape memory, super elasticity, and high damping qualities compared to Stainless steel 316L (SS316L). In this present study, the input process variables such as voltage, wire-feed rate, dwell time and argon gas flow rate have been maintained constantly (fixed) based on the trial experiments. The metallic biomaterials (Stainless steel 316L (SS316L) and Nickel-titanium alloy (NiTi)) are fabricated using a wire-arc additive manufacturing process and it is utilized to study the mechanical properties such as tensile, yield strength and % elongation. The additive manufactured biomaterials such as Stainless steel 316L (SS316L) and Nickel-titanium alloy (NiTi) have been compared and studied the impact of biocompatibility (Cytotoxicity) and anti-bacterial property for surgical implant applications. From the result, it has been found that the shape memory alloy (NiTi) has higher ultimate tensile and yield strength than the Stainless steel 316L (SS316L) due to its high corrosion resistance, super elasticity, and shape memory behaviour. In addition, the cytotoxic effects of both biomaterials (SS 316L and NiTi alloy) on L929 mouse fibroblast cells were examined in the cell culture media. The biocompatibility and anti-bacterial characteristics of SS 316L and NiTi alloy has been investigated, which would support its use as a surgical implant.
Experimental Investigation of the Surface Topography in Terms of Process Parameters During Picosecond Laser Machining of Polycrystalline Diamond
Authors: Zhang Yushun , Han Fuzhu 
Published: September 2023

Abstract
Because of its significant impact on the friction and surface quality of a cutting process, the surface topography of the flank face is one of the most crucial indicators for the quality of Polycrystalline Diamond (PCD) cutting tools machined with ultrafast laser. Therefore, it is necessary to study the effect of process parameters on the topography of the machined surface. In this study, a picosecond laser with 1064nm wavelength was used to generate and polish kerfs on PCD samples. An orthogonal experiment was conducted to evaluate the impact of process parameters on surface roughness. The results indicated that the surface roughness decreased with increased pulse energy, polishing depth, or decreased laser polishing speed. As the number of polishing cycles increased, the surface roughness tended to first decrease and then increase. The results of variance analysis demonstrated that the polishing speed and polishing depth have a significant impact on the surface roughness. Additionally, surface topography and microgrooves formed on the side wall of the kerfs were studied using a digital microscope. Finally, process optimization was carried out based on the previous experiment. A surface roughness of Ra0.16μm was obtained and recasting layer was fully removed. This study shows that the surface topography of the flank face of PCD cutting tools can be improved with an appropriate combination of the cutting depth, cutting speed, number of polishing cycles, and pulse energy during ultrafast laser processing.
Intelligent Uncertainty Handling Using Artificial Neural Networks in a Programmatic Logic Controller-Based Automation System
Authors: Lai Enoch , Ma Jianfeng 
Published: September 2023

Abstract
The manufacturing industry is relying more and more on artificial intelligence (AI). Despite this, Programmable Logic Controllers (PLCs), one of the most common industrial tools, still lack AI integration. This means that PLCs are still very rigid and struggle with handling uncertainties. Uncertainties are input data that the controller has not been programmed to address. Uncertainties can be caused by variation in sensor data or other factors. Because PLCs struggle to handle uncertainties, this makes them very tedious to program. Implementing AI into the PLC may eliminate this problem. This study answers the question of whether AI can be implemented into a PLC (Allen-Bradley). To do this, a Levenberg-Marquardt backpropagation artificial neural network (ANN) was trained in MATLAB to approximate a mathematical function. A representation of the ANN was then constructed using the PLC ladder logic diagram by implementing the weight and bias values obtained from the trained ANN. The PLC-implemented ANN’s results were validated by comparing its output values to those of MATLAB trained ANN. Negligible differences between the outputs indicate that implementing an ANN framework into the PLC ladder logic code is viable. The ability to implement an ANN into the PLC code may help PLCs handle uncertainties better. This implementation may help the PLC become more versatile for more jobs and may also make it easier to program. Future studies should test out this method of implementation and apply it in real world applications.
Experimental Analysis on Tissue Fracture in Needle Insertion Process
Authors: Hu Yingda , Du Shilun , Lei Yong 
Published: September 2023

Abstract
During needle insertion procedures, the insertion of the needle is accompanied by tissue fracture, which is the result of needle tissue interactions. The tissue fracture toughness is an important parameter to describe the resistance of tissue to crack generation, as well as to quantify the energy absorbed by the tissue during crack propagation. Fracture toughness can be affected by many factors, such as needle insertion speed, needle tip bevel angel and tissue Young’s modulus. However, existing studies on fracture toughness estimation did not consider the effect of Young’s modulus. In this paper the influence of three major factors on fracture toughness, specifically, insertion velocity, needle diameter and tissue Young’s modulus, are systematically studied. testbed is constructed, and the experiments are designed using polyvinyl alcohol tissue phantom with different insertion velocity, needle diameter and Young’s modulus. Experiments results show that the fracture toughness is positive proportional to insertion velocity, and Young’s modulus, and negative proportional to needle diameter. In addition, the sensitivity analysis shows that the effect of Young’s modulus to fracture toughness is less than other influencing factors.
Process Planning for Hybrid Manufacturing: Ball Nose End Milling and Direct Energy Deposition of Stainless Steel
Authors: Hughes Zane Weldon , Siller Hector R. 
Published: September 2023

Abstract
Hybrid manufacturing can combine additive and machining processing to create parts that would otherwise require two or more machines and can provide many beneficial opportunities in the manufacturing industry. This paper details the creation and application of a generalized process plan for the hybrid manufacturing of AISI 316L stainless steel, using direct energy deposition (DED) and ball-nose end-mill machining; that includes the inspection and measurement of objects created by that hybrid manufacturing process plan. The proposed process plan progresses through the selection of substrate thickness, single-track, multi-track, and multi-layer depositions, then on to machining processing. A manufacturers’ recommended set and range of DED parameters were used to create a designed experiment that aided in the analysis of objects created in each of the DED process planning steps; those objects were then machined in the same enclosure using a set of machining parameters screened from industry recommendations for ball-nose milling of stainless steel, after which measurements were taken for surface roughness, some material characteristics, and for tool deterioration. The results, analyses, and discussions collected herein show that the proposed process plan can provide models for geometrical outputs for each step in the plan, some improvements in substrate stability, surface roughness, tool deterioration, and material porosity due to voids. Current research in hybrid manufacturing does not show generalized process planning influences. The process plan, as demonstrated by the work in this paper will help operators, designers, and researchers in the future by defining a generalized workflow that can be applied to other materials used in the form of hybrid manufacturing that combines DED with machining processes.
An Investigation on 3D Bio-Printed Scaffold Shape Fidelity Incubated in a Custom-Made Perfusion Bioreactor
Authors: Mankowsky Jack , Quigley Connor , Clark Scott , Habib MD Ahasan 
Published: September 2023

Abstract
Three-dimensional (3D) bioprinting is a promising technique for creating patient-specific 3D scaffolds of tissues or organs. An appropriate culturing process is critical to confirm encapsulated and seeded cells’ excellent viability and proliferation into scaffolds materials. Traditional stagnant cell culturing methods don’t ensure entering medium inside areas or passing through the scaffolds. To resolve this issue, we developed a customized perfusion bioreactor to supply the growth medium dynamically to the encapsulated or seeded cells. Our custom-designed bioreactor improves the in vivo stimuli and conditions, which may enhance cell viability and proliferation performance. A design of a dual medium tank was utilized allowing the replacement of already-used medium without interrupting perfusion. Accommodating an array of cassettes in a newly designed perfusion chamber allowed a wide range of scaffolds with various size and shapers to hold. In this paper, we explored fluid flow response on scaffolds fabricated with various material compositions with different viscosities. We fabricated scaffolds following a 00–900 deposition pattern with 8% Alginate, 4% Alginate-4% Carboxymethyl Cellulose (CMC), and 2% Alginate-6% CMC incubated, allowing a constant fluid flow for various periods such as 1, 2, 4, and 8 hours. The change of scaffolds fabricated with multiple material compositions was determined in terms of swelling rate, i.e., change of filament width, and material diffusion, i.e., comparison of dry material weight before and after incubation. This comparative study can assist in application-based materials selection suitable for incubating in a perfusion bioreactor.