bluuebunny/crossref_metadata_2025_split huggingface dataset:
Usage of an Interactive Learning Platform in Project-Based Graduate Courses for the Preliminary Design of Axial Turbines
Authors: Gomes Dias Marcelo Marques , Tozi Luiz Vitor , de Oliveira Silva George Patton , Tomita Jesuino Takachi , Bringhenti Cleverson 
Published: September 2023

Abstract
The industry and the academy are continuously developing new approaches, technologies, and models for gas turbine design. However, there was not enough time to cover all the relevant subjects for undergraduate or graduate students in one or two-semester courses. So, in previous works, the authors described a developed interactive platform for the preliminary design of multistage axial flow turbines for uncooled blades and improved it based on the student’s feedback, so it could be as didactic as possible. Its application in the courses offered by the Turbomachines Department at Aeronautics Institute of Technology (ITA) successfully accelerated the learning process of the basics. In the graduate courses, the use of the program granted time to more complex topics, e.g., blade cooling, off-design performance, CFD simulations, manufacture, and machine learning applied to turbomachine design, which were not covered in previous years. The program initiates with the data from thermodynamic cycle calculation and the definition of the main design parameters. Then, it computes the aerothermodynamic properties of the flow stage-by-stage, from hub to tip, and the geometry of the blades. Finally, it estimates the losses by source, iteratively, through the models of Ainley and Mathieson [1], Dunham and Came [2], or Kacker and Okapuu [3]. This work presents some studies performed by the students using the platform. Firstly, it was varied some design key parameters such as loading and flow coefficients, the aspect ratio and the pitch-to-chord ratio of the blades, the airfoil section geometry, and the tip clearance, once at a time while maintaining the others. Then, it was possible to observe how these modifications affected the number of stages required, the stress levels, the machine size, and the isentropic efficiency, tracking the primary sources of loss. After, the students implemented other loss models, such as the one by Craig and Cox [4], aiming to analyze the effect of surface roughness on the losses. Finally, they compared the platform results with CFD simulations and experimental data from turbines developed at the Department. The paper concludes with the students’ insights through the project and comments on how the employed methodology improved their learning process.
Design and Cooling Performance of Additively Manufactured Ceramic Turbine Vanes
Authors: Fox Andrew , Lynch Stephen , Young Jason C. , Frick Carl P. , Hankins Jennifer , Kuhn Kyle , Brinckmann Stephan A. , Fertig Ray S. 
Published: September 2023

Abstract
Ceramic materials are of significant interest in aviation and power generation gas turbine engines due to their low density and ability to withstand high temperatures. Increased cycle thermal efficiency and higher specific power output is possible by incorporating ceramic components that enable high turbine inlet temperatures and lower required cooling airflow levels. However, ceramics can be difficult and costly to form into the complex shapes used in gas turbine components, often requiring specialized multi-step processes. Furthermore, ceramic components in the hottest areas of a gas turbine, such as vanes or blade shroud seals, will still likely require cooling which is challenging to implement in conventional ceramic manufacturing approaches. Therefore, this study presents a multidisciplinary approach that investigates the design, fabrication and overall cooling effectiveness evaluation of additively manufactured (AM), polymer derived ceramic (PDC) turbine vanes. A thermo-mechanically optimized vane design was generated, ceramic additive manufacturing of the complex cooling configuration was developed, and quantification of the increase in overall cooling effectiveness was performed in a 1X scale, high-speed facility using infrared thermography. This study produced a PDC AM process, capable of printing complex internal cooling schemes in 1X scale turbine vanes. It was found that the optimized vane more than doubled the overall cooling effectiveness observed in the baseline design, which reasonably agreed with thermomechanical optimization model predictions. Additionally, the optimized ceramic vane outperformed an identical metal vane, in terms of area averaged cooling effectiveness, suggesting that the ceramic vane could operate at reduced coolant flow rates to achieve comparable levels of cooling performance.
Progress Toward Climate-Friendly Aviation in the ARPA-E ASCEND and REEACH Programs
Authors: de Bock H. Peter , Tew David E. , Rahman Zaiur , Lecoustre Vivien , Cox-Galhotra Rosemary A. 
Published: September 2023

Abstract
The decarbonization of commercial aviation in the coming decades represents a formidable challenge. For ranges of less than several hundred miles, all-electric battery-powered aircraft have the potential to be attractive solutions. However, for longer ranges, the appreciably greater specific energy of fuels will continue to be required. Nevertheless, our climate crisis mandates that these fuels must be synthesized in a carbon-neutral manner, and consequently, they are likely to be considerably more expensive than their fossil-derived counterparts. These challenges will result in even more impetus to make future propulsion systems more efficient — regardless of whether that energy is contained within batteries or fuels. Electrified propulsion systems are potential enablers for our transition to this future through their ability to facilitate the integration of disparate storage and conversion technologies into a single hybrid system that offers high conversion efficiency at an acceptable weight. In this paper, progress made in the development of such systems within the ARPA-E ASCEND and REEACH programs is described.
Effect of Hot Gas Path Component Corrosion on the Performance of Hydrogen Fueled Micro Gas Turbines
Authors: Hashmi Muhammad Baqir , Mansouri Mohammad , Breuhaus Peter , Lemma Tamiru Alemu 
Published: September 2023

Abstract
Micro gas turbine (MGT) is a promising technology for decentralized energy systems because of its wide range of benefits, such as fuel and operational flexibility, power density, combined heat and power efficiency, and lower emission levels as compared to its conventional counterparts. The stringent climate policies to overcome challenges caused by global warming demand significant measures including use of alternative fuels. Among low emission fuels, hydrogen might pose several challenges owing to its distinct chemical and physical properties. One of the potential challenges is the significant changes in exhaust gas fluid properties, such as relatively enhanced level of steam/moisture content in the flue gas. The varied exhaust gas fluid properties might generate both thermal stresses and considerable wet corrosion in the turbine section of gas turbine. This challenge becomes more susceptible in retrofitted gas turbines where combustor is replaced, while the rest of the turbomachinery remains same. Therefore, hot gas path components of gas turbines may face health degradation and subsequent performance deterioration and reduced lifetime.
The aim of this paper is to compare the effect of injected corrosion faults on the thermodynamic performance deterioration of both H2 and natural gas (NG) fueled MGT. In this regard, this study first presents an experimentally validated simulation model of a 100 kW MGT using a commercially available software tool, GasTurb. The study compares the thermodynamic and combustion flue gas properties of both hydrogen and NG fueled MGT at full load conditions. The combustion reactions and detailed analysis of fluid flow properties manifested that H2 fuel utilization results in an increased steam content (by ∼106%) as compared to NG combustion. The combined effect of turbine corrosion severity level and high ambient temperature on the overall performance of the MGT is also studied. The study shows that the increased corrosion severity level at high ambient temperature can lead to deterioration in power and thermal efficiency. The findings of the present study might be helpful in designing new hot gas path components, and fuel accessories to upgrade the existing fleet of MGTs, while using hydrogen-rich fuels resulting in enhanced performance, and reliability.
GPU-Accelerated Implicit Turbomachinery Flow Solver Using Multiple MPI Communicators
Authors: Wang Feng , di Mare Luca 
Published: September 2023

Abstract
This paper describes a procedure to port an unstructured CFD solver to GPU for turbomachinery simulations via NVIDIA OpenACC. Matrix-free implicit time stepping is used for robust and efficient time integration. Data movement between the device and the host is managed explicitly and is minimized for optimal performance. For multiple GPU computations, a flexible multistage decomposition is devised. The computational domain is first divided into different components (or sub-domains), each of which represents an physical entity, such as a bladerow. For each subdomain, a graph partition is then performed. Data exchange among multiple GPUs are devised to accommodate such domain decomposition strategy. For halo exchange within each sub-domain, data can be sent directly from one GPU to the other one if permitted by the hardware. To exchange data among different sub-domains, a general purpose coupler is devised to exchange data among the GPUs via the host. In terms of computational speed, for a socket-to-socket comparison (one V100 and 20 CPU cores), the GPU code shows a global speedup of 8.1 for double precision and 10.1 for single precision. Furthermore, the GPU code is 5.5 and 6.9 times more energy efficient for double and single precisions, respectively. The GPU code is validated on Rotor 37 and a high speed multistage compressor. Good agreement with rig data is observed for both cases. The multistage compressor case has roughly 17 million cells and it takes the GPU code 8 hours to produces 4 revolutions using 4 V100. The developed GPU code represents a flexible computational framework for future multi-fidelity/physics simulations on heterogeneous computing environment.
Centrifugal Compressor Polytropic Performance Evaluation: Taher-Evans Methods
Authors: Taher Matt , Evans B. F. 
Published: September 2023

Abstract
The polytropic compression process is defined as a reversible and non-adiabatic process, in which the ratio of useful compression work to the change of enthalpy remains constant along the polytropic compression path. Unlike an isentropic process, the polytropic process accounts for unavoidable degradation of energy as governed by the second law of thermodynamics. Polytropic efficiency can be very accurately calculated by numerical integration along a defined path or by much less accurate, older polytropic exponent methods in a closed form solution.
The Taher-Evans numerical integration methods for the calculation of polytropic performance of centrifugal compressors are based upon a constant efficiency, temperature-entropy polytropic path represented by a mathematical model employing cubic polynomials.
In earlier papers published by the authors on Taher-Evans methods, the maximum relative deviation limit used for judging solution certainty of the calculation of the polytropic efficiency and polytropic work was chosen as ≤ 0.001% to show the high accuracy of Taher-Evans methods. The uncertainties associated with the realities of measured test data to determine a fluid’s thermodynamic and thermophysical properties using equations of state, however, may impose constraints on the overall accuracy for the calculation of the polytropic efficiency and the polytropic work in factory or field performance testing of centrifugal compressors in accordance with ASME PTC-10. In this paper, the use of Taher-Evans methods is explained for the factory and field test conditions that are required to achieve a relaxed maximum relative deviation limit ≤ 0.01% for reporting the calculation of the polytropic efficiency and polytropic work. For ASME PTC-10 type 1 and type 2 tests, this paper presents the selection criteria for the maximum number of sequential Taher-Evans cubic polynomial segments needed to achieve target relative deviations of either 0.001% or 0.01%.
Example cases confirm that the Taher-Evans cubic polynomial methods yield highly accurate results while requiring fewer computing resources and reducing computing elapsed time compared with other endpoint or multi-step numerical methods. Also, a new relationship with a condensed expression is developed to precisely calculate the real gas polytropic volume exponent at each point along the polytropic path.
Additively Manufactured NiTiHf Shape Memory Alloy Transformation Temperature Evaluation by Radial Basis Function and Perceptron Neural Networks
Authors: Abedi Hossein , Abdollahzadeh Mohammadjavad , Almotari Abdalmageed , Ali Majed , Mohajerani Shiva , Elahinia Mohammad , Qattawi Ala 
Published: September 2023

Abstract
Employing Laser Powder Bed Fusion (LPBF) method to manufacture NiTiHf Shape Memory Alloy (SMA) is becoming more common. The major design property for NiTiHf is the transformation temperatures (TTs) which control the activation threshold of the SMA material and enable it to create the shape change due to a microstructure phase transformation. Given the high number of fabrication factors, machine learning (ML) approaches provide a promising approach to the design of SMA to control the TTs.
The main obstacle to using ML methods is the need for an established correlation between fabrication features and material properties. The presented work develops an ML approach to enable the prediction of the TTs for additively manufacturing NiTiHf. The work uses all available experimental data on additively and conventionally manufactured NiTiHf. Selected fabrication features included in the ML models consider the elemental compositions of NiTiHf, laser power, laser speed, hatch spacing, and almost all the processing steps historically used to manufacture, or heat treat the NiTiHf for SMA.
Multiple models of Multi-Layer Perceptron (MLP) and Radial Basis Function (RBF) Neural Networks (NN) are developed to predict the TTs of LPBF-manufactured NiTiHf. The models successfully predict the TTs for various NiTiHf fabrication conditions.
Systemic Control of 3D Bioprinting Process Parameters to Achieve Defined Scaffold Porosity
Authors: Quigley Connor , Tuladhar Slesha , Adhikari Samrat , Habib MD Ahasan 
Published: September 2023

Abstract
Due to its inbuilt ability to release biocompatible materials encapsulating living cells in a predefined location, 3D bioprinting is a promising technique for regenerating patient-specific tissues and organs. Among various 3D bioprinting techniques, extrusion-based 3D bio-printing ensures a higher percentage of cell release, ensuring suitable external and internal scaffold architectures. Scaffold architecture is mainly defined by filament geometry and width. A systematic selection of a set of process parameters, such as nozzle diameter, print speed, print distance, extrusion pressure, and material viscosity, can control the filament geometry and width, eventually confirming the user-defined scaffold porosity. For example, carefully selecting two sets of process parameters can result in a similar filament width. However, the lack of availability of sufficient analytical relations between printing process parameters and filament width creates a barrier to achieving defined scaffold architectures with available resources. In this paper, filament width was determined using an image processing technique and an analytical relationship was developed, including various process parameters to maintain defined filament width variation for different hydrogels within an acceptable range to confirm the overall geometric fidelity of the scaffold. Proposed analytical relations can help achieve defined scaffold architectures with available resources.
Review of Interventional Robotic Systems
Authors: Liu Yang , Li Dian-Ru 
Published: September 2023

Abstract
The success of the da Vinci system has shown the feasibility and a great potential of using robotic systems to improve healthcare. With a trend of replacing more and more invasive surgeries with minimally invasive interventional procedures, developing robotic systems for interventions has seen a boost of interest from both the industry and the academia in the past two decades. Using robotics to conduct intervention procedures is expected to better protect the clinicians by reducing their radiation exposure and to create better patient outcome in cases where high positional accuracy is needed, such as placing a stent or a coil. However, adoption of interventional robotics has been slow due to the limitations of current interventional robotic systems such as a steep learning curve, lack of haptic feedback, and safety concern. This narrative review first introduces the current clinical applications of interventional robotic systems and their limitations. The major technological features of interventional robotics, including the master-slave manipulator, soft continuum robot, and end effector, are then described. Finally, several manufacturing research topics are proposed for future interventional robotic systems.
Powder-Binder Interaction in Binder Jetting Process: A Simulation Study on Bimodal Powders
Authors: Shahed Kazi Safowan , Manogharan Guha 
Published: September 2023

Abstract
Binder Jetting (BJT) is a room-temperature powder-bed additive manufacturing process suitable for a wide range of materials such as bioceramics, sand, metals, and polymers. In this process, powder-binder interaction, which is influenced by the powder bed packing density during the printing process, has a major impact on the overall part quality. Although few recent studies have explored the modeling of the binder-jetting process, they are not realistic (e.g., 200 % larger droplet size when compared to the actual process). This study is the first to report a systematic study into the powder-binder interactions for bimodal powders with actual binder-jetting conditions across a wide range of packing densities and binder-jetting conditions. This integrated Discrete Element Modeling (DEM - powder spreading) – VOF (Volume of Fluid - binder interaction) study analyzed the powder-binder interaction in terms of: penetration depth, spreading time, and area per droplet on the powder bed. It was observed that an increase in droplet velocity resulted in deeper penetration (5.4%) of the binder but reduced the area of spread (20.8%) across packing densities. In addition, for a given droplet size and packing density, an increase in droplet velocity resulted in a shorter spreading time (27.3%). Findings from this study provide a new understanding of the temporospatial characteristics of the binder-powder interaction, which helps in identifying optimal printing parameters for a bimodal powder feedstock.
Effect of Blown Powder Directed Energy Deposition Angle On Overspray Contamination
Authors: Heinrich Lauren , Kannan Rangasayee , Burl Alan , Nandwana Peeyush , Fillingim Kenton , Feldhausen Thomas , Kurfess Thomas , Saldaña Christopher 
Published: September 2023

Abstract
Blown powder directed energy deposition (DED) hybrid machine tools are particularly beneficial when the net shape of a component is to be manufactured in an additive and machined interleaved fashion. This investigation seeks to analyze the effect of the additive head lean angle relative to the part on blown powder DED surface contamination due to overspray. These hybrid DED platforms are commonly installed on multi-axis machining systems where the lean of the deposition head relative to the component surface can be controlled by tilting the component. The blown powder DED process has a 10–50% lower catchment efficiency as compared to wire fed DED systems. This excess powder is still fed towards the deposition location where the particles are heated by the laser and rebound off the melt pool. Some of these heated particles impact the previously machined thin-wall surface. While the deposition process and tool path planning process has been evaluated, the effect of the overspray due to lean angle of the deposition head on the previously thin-wall machined surface is not yet fully understood. This investigation found that minimum lean angle coincides with minimal overspray effect with nearly no contamination. If a lean angle is required, the maximum lean angle possible should be implemented for the smallest effected overspray area on the machined surface which was found to decrease the affect zone by half compared to intermediate lean angles. A diameter divergence was also noticed as the deposition angle was increased. In this study, a thorough analysis of the surface and geometric effects when depositing thin-walled components at varying angles is completed. It has been shown that part quality can be significantly affected by lean angle and thus must be incorporated as an additional design consideration in the manufacturing process.
Laser Welding With and Without Filler Wire of Aluminum Thin Sheets in Different Semi-Finished Formats
Authors: Perez Zapico Eriel , Ascari Alessandro , Liverani Erica , Fortunato Alessandro , Dimatteo Vincenzo 
Published: September 2023

Abstract
Laser welding of aluminum sheets gained an increased interest in the last few years, especially for the production of lightweight components. One of the most critical factors to be taken into consideration in this particular application is the formation of pores in the fused zone, that strictly depends on the semi-finishing format of the parent sheets. In particular, in fact, when one or more parts are produced by means of high-pressure casting or additive manufacturing, this phenomenon is amplified and optimization of process strategies and parameters is of utmost importance for achieving a sound joint. According to these considerations the present paper deals with welding of AA6082 sheets with additively manufactured AlSi10 ones in a configuration that is typical for the production of battery cases for the e-mobility field. In order to understand the role of process strategies on weld bead quality, both autogenous welding and welding with filler wire are investigated and the eventual benefits of applying a wobbling beam shaping is also considered. For any of the above-mentioned strategies, the role of process parameters, such as laser power, welding speed, filler wire speed and wobbling, is investigated, with particular reference to the formation of pores and defects. Porosity is analyzed as the main driver for the definition of weld bead quality and also weld bead shape and geometry are analyzed.