bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Literature Review on Data Sources and Methodologies for Enriching Gas Path Analysis With Earth Observation Data
Authors: Seume Erik , Göing Jan , Friedrichs Jens 
Published: August 2024

Abstract
Aero engine performance and condition deterioration are a function of operational severity. Operational severity is determined by various aspects such as airborne contaminants, derates, ambient temperature, humidity, and precipitation. More severe operating environments induce cost, which should be managed by using earth observation (EO) data in engine health monitoring. This paper presents an analytical approach that incorporates a broad set of EO data into engine health management and subsequent maintenance planning. Current approaches to gas path analysis are extended by incorporating EO data. The analytical approach is presented in combination with a literature review. The literature review covers the following topics: flight trajectory modeling, EO/environmental condition data, as well as engine performance, condition, and deterioration modeling. Methods and data sources in these different areas are reviewed while simultaneously presenting the currently researched analytical approach. The researched analytical approach creates high-resolution contamination profiles for a flight trajectory on a global scale. Weather conditions and the ingestion of aerosols and sand are monitored and correlated with aero engine condition and performance. A wide range of data sources are presented, which however only partly cater to the needs of the Maintenance, Repair and Overhaul community.
Lattice-Boltzmann Modelling of Internal Compressible Flows: Application to the Transonic LS89 Cascade
Authors: Tsetoglou Iason , Zhao Song , Jacob Jérôme , Boivin Pierre 
Published: August 2024

Abstract
In this work the D3Q19 Hybrid Recursive Regularized Pressure based Lattice Boltzmann Method presented by Farag et al. (2021) is assessed for the simulation of complex transonic internal flows. A Lattice Boltzmann solver presented by Jacob et al. (2018) treating the mass and momentum conservation equations is coupled with a finite volume scheme for the resolution of the conservative form of the total energy equation as shown by Zhao et al. (2020), leading to a fully numerically conservative scheme. The well documented case of the high-pressure turbine guide vane cascade with the VKI LS89 profile is examined. To the authors’ knowledge, this is the first numerical aero-thermal investigation of this configuration using a Lattice Boltzmann approach. An appropriate numerical domain along with a grid refinement technique are used to accommodate a Cartesian grid while ensuring flow periodicity downstream of the cascade in the pitch-wise direction. This is verified thanks to the time-averaged profiles of the exit isentropic Mach number and exit isentropic Reynolds number. The solid boundary is introduced in the Cartesian grid with a cut-cell immersed boundary technique where the boundary nodes of the domain are outside of the solid. An efficient treatment for these nodes is used to accurately represent the near wall flow dynamics. An explicit power-law velocity wall model is used to accurately predict the near wall velocities. A logarithmic temperature wall function is also added to this method to improve the convective heat transfer estimation on the blade surface. The results of this study are compared to experimental and numerical results found in literature, proving the LBM to be a viable approach for compressible internal flows.
Phase Prediction Methodologies for Rapid Screening of High Entropy Alloys
Authors: Mohammadi Aron , Tsang Jonathan , Huang Xiao , Kearsey Richard 
Published: August 2024

Abstract
Increasing gas turbine hot section temperatures is a venue to improve fuel efficiency, thus pushing the need for new, higher temperature resistant materials. Experimental results show that high entropy alloys (HEAs), consisting of near equiatomic amounts of various metallic elements with no clear solvent, exhibit excellent high temperature mechanical properties, corrosion resistance, and good strength to weight ratios. This has resulted in significantly increased interest in studying HEAs for potential gas turbine application over the past decade. The properties of HEAs tend to be highly sensitive to phase composition; however, pre-existing phase prediction methodologies used for traditional alloy compositions, with a clearly defined solvent, are generally not well suited to HEAs. Additionally, the combination of the vast design space and complex elemental interactions render experimental exploration of new HEAs unfeasible at scale, necessitating higher throughput methods. Computer aided calculation of phase diagrams and first principal calculations are well established methods for predicting the phase structure of hypothetical alloy compositions, however they tend to be very computationally intensive and thus their speed is highly limited by available hardware. Two prediction methods capable of rapidly screening candidate composition are empirically developed design parameters based on values derived from the elemental composition of the alloys and machine learning models trained using available experimental HEA phase compositions. This simplifies the calculations and the input parameters required for both methodologies are readily available. This work compares the effectiveness of a variety of empirical design parameters and a pre-trained machine learning model, based on a convolutional neural network architecture, at predicting the resultant phases in various HEA compositions, including the W-Nb-Mo-Ta-Ti-Zr alloy system.
Development of a Novel Hydrogen Burner Using Additive Manufacturing
Authors: Kim Shaun , Kim Jupyoung , Byun Hosung , Ku Jae Won , Do Hyungrok , Kwak Sanghyeok , Han Dongsik , Jung Seungchai , Park Heeho 
Published: August 2024

Abstract
In the aerospace industry, hydrogen has been embraced as a gas turbine fuel. Hydrogen combustion holds significant promise for enabling zero CO2 emissions. However, the transition from hydrocarbon to hydrogen fuel presents new challenges. Designing hydrogen combustors with low NOx emissions across a wide operability range, spanning flashback to lean blowout, requires intensive work, both numerically and experimentally. In this study, a design for an expandable micromixer-type hydrogen combustor is presented. The core design features square fuel rods, each equipped with four orifices for injecting gaseous hydrogen streams, which are rapidly mixed by crossflow to form microflames. Within each fuel rod, a triply periodic minimal surface structure is designed to serve as both a support material and a heat sink for transferring heat from anchored microflames. To achieve a wide operability range, two sets of fuel rods, namely pilot and main burners, are separately controlled with different fuel splits. To maximize the number of flames while preventing flame interaction, these burners were arranged in a staggered grid pattern, with a 45° offset in their orientation. Large eddy simulation (LES) with finite-rate hydrogen-air chemistry was implemented, and the numerical methods were validated by comparing their results with experimental results. The results of LES with the reduced Mevel mechanism were consistent with the test results. The use of additive manufacturing with Ni-based alloy powder significantly reduced the lead times for variant tests, enabling the rapid development and iteration of burner designs. Single-burner tests were conducted under atmospheric conditions, and each configuration was tested with and without confinement using quartz tubes. The presence of an outer recirculation zone improved the resilience of the burner to lean blowout. The LES exhibited good performance in predicting combustion instability under selected conditions. Future works will consider optimizing burner designs and conducting multiburner test under elevated conditions.
Remaining Useful Life Prediction of Aircraft Engine Based on Bi-LSTM Network Integrated With Attention Mechanism
Authors: Qu Guixian , Qiu Tian , Ding Shuiting , Ma Long , Yuan Qiyu , Ma Qinglin , Si Yang 
Published: August 2024

Abstract
Predicting the remaining useful life (RUL) of an aircraft engine is crucial for ensuring the reliability and safety of an aircraft. This study has developed a novel data-driven hybrid network combining a Bidirectional Long Short-Term Memory (BiLSTM) with an attention mechanism to predict the RUL in aircraft engines. The model introduces an innovative approach by incorporating the feature-capture attention mechanism before the BiLSTM layer, which enhances the model’s focus on relevant sensor data segments to enable more effective feature extraction from multi-sensor data. This integration significantly enhances prediction accuracy compared to traditional shallow and deep learning models by leveraging the BiLSTM’s capability to analyze time-series data in both forward and backward directions. The proposed model demonstrates superior accuracy through comparative experiments conducted on the NASA C-MAPSS dataset, underscoring its potential to advance malfunction prediction and health management in aircraft engines.
Experimental and Numerical Study on the Effect of OGV Clocking on ICD Performance
Authors: Jonsson Isak , Capitao Patrao Alexandre , Miltén Petter , Xisto Carlos , Lejon Marcus 
Published: August 2024

Abstract
This paper presents a numerical and experimental investigation into the effects of compressor clocking and stage interaction on the performance of multi-stage axial compressors. The study focuses on the aerodynamic impact of the interaction between the intermediate compressor duct (ICD) and low-pressure compressor (LPC) outlet guide vanes (OGV). Experiments were conducted in Chalmers 2.5 stage low-pressure compressor facility, and numerical simulations were performed using a commercial CFD solver with a Reynolds-averaged Navier-Stokes (RANS) turbulence model. The results show that the clocking position can impact the OGV-ICD performance up to 3% compared to baseline with the dominant effects in the ICD where wake interaction impact transition and the secondary flow structures such as the radial traverse of the hub corner separation. This research provides valuable insights into the role of clocking in ICD design and performance, highlighting its importance as a design parameter. The study is the first to implement IR-thermography for flow visualization in a ICD under engine representative operational conditions.
Numerical Investigation for a Rotating Cavity With Axial Throughflow With Both Axial Heating and Radial Heating
Authors: Zhao Yu , Ding Shuiting , Qiu Tian , Xu Yang , Liu Peng 
Published: August 2024

Abstract
This paper investigates the flow and heat transfer mechanisms of the rotating compressor cavity with axial throughflow under the thermal boundary superimposed by axial and radial heating. In contrast to previous studies, which mainly focused on radial heating, the axial temperature difference increases with the increase of the single-stage compression ratio and is therefore considered in this paper. Verified numerical simulations were used for the study, and the similarities and differences caused by superimposed axial heating were analyzed by comparing situations involving both radial and axial heating, radial heating with a small temperature difference, radial heating with a medium temperature difference, and radial heating with a large temperature difference. The effect of superimposed axial heating on the flow and heat transfer in the cavity was studied under three different Rossby numbers and three different axial temperature differences. The results indicate that the superimposed axial temperature gradient alters the flow field and temperature field in the disk cavity, resulting in different Nusselt numbers for the disk and shroud compared to the case of radial heating only. At low Ro, the buoyancy driven flow is more sensitive to the thermal boundary, so the flow field variation is dominant, and the heat transfer of the high and low radius of the disk varies with different axial temperature differences. At high Ro, the pressure driven flow field is insensitive to the thermal boundary, so the temperature field variation dominates, and the heat transfer of the high and low radius of the disk changes uniformly with different axial temperature differences.
Design and Performance Analysis of a Fuel Cell Propulsion System Driven by a Hydrogen-Fired Micro Gas-Turbine
Authors: Lück Sebastian , Göing Jan , Nachtigal Philipp , Mimic Dajan , Friedrichs Jens 
Published: August 2024

Abstract
A novel design for the cathode air supply system of a fuel cell-based aircraft propulsion system is presented in this study. Herein, the state-of-the-art Electrically driven Cathode air Supply system (ECS) is replaced by a H2-fuelled micro gas turbine (GTCS) with the main goals of 1) decreased total fuel cell power demand and, therefore, 2) reduced low temperature waste heat. Therefore, no parasitic power is required to drive the cathode air supply. The proposed system design is simulated for a regional, distributed propulsion aircraft. Adaptation to other aircraft layouts is easily possible. The operating characteristics of both systems are compared and advantages of the novel architecture are quantified. The advantages are, among others, a substantial reduction of the fuel cell waste heat as well as the reduction of the overall component size within the air supply system. For the most demanding operating point take-off, fuel cell waste heat can be reduced by 25% at maximum operating pressure while heat exchanger size is decreased by up to 16% and humidifier size by up to 20%. Further synergies from the novel architecture are the possibility to use up to 45% of hydrogen from the anode exhaust in the combustor instead of recirculating or venting it. This may lead to a substantial size reduction in the anode side recirculation cycle. Considering the overall system weight, the novel system can achieve a 26% lower weight than the state-of-the-art ECS system. The fuel consumption however is up 9.6% above the ECS system due to poor thermal efficiency of the core. However, it remains to be evaluated in the context of overall aircraft design whether the advantages in component size and weight due to reduced waste heat rejection requirements can outweigh the drawbacks in fuel consumption.
Numerical Prediction of Inlet Geometry Influence on the In-Duct Acoustics of Small Centrifugal Compressors
Authors: Broatch Alberto , Navarro Roberto , García-Tíscar Jorge , Roig Ferran 
Published: August 2024

Abstract
Small centrifugal compressors are employed to boost automotive internal combustion engines or hydrogen fuel cells, amongst other applications. In many scopes, the overall intensity and quality of noise emission is a major concern, so many researchers develop and assess numerical models to predict acoustic spectra. In this work, Detached Eddy Simulations (DES) of a vaneless centrifugal compressor are conducted to assess the impact of intake geometries on its aeroacoustic performance. Experimental measurements are employed as a means of validation. Flow field analysis and Dynamic Mode Decomposition allow us to analyze the underlying mechanisms of the most relevant acoustic features. This work provides insight into the implications for noise generation of employing tight elbows due to packaging constraints.
Analysis of Complex Total Pressure Distortion Screens Using 1-Dimensional Loss Data
Authors: Gillespie John , Hayden Andrew , Lowe Todd , Untaroiu Alexandrina , Nessler Chase 
Published: August 2024

Abstract
Producing a screen for use in generating an accurate, complex total pressure distortion, involves solving two distinct problems. First, the basic loss characteristics of wire mesh screens must be established. Second, the interaction between multiple regions with different loss coefficients (as seen in a complex screen) must be accurately accounted for. Both tasks must be solved effectively to design an accurate screen. For the first goal, we present a comprehensive data set of correlations for the losses generated by a wire mesh, stacked on top of a “backer” support screen. While some publicly available data exists for the losses induced by a single mesh on its own, the losses in a real total pressure loss screen are dependent on the interaction between the backer and the loss meshes. As a result, the data presented here includes the effects of the backer. For the second task, as flow encounters a screen composed of many meshes, it redistributes itself such that the flow rate is higher through the low-loss regions and lower through the high-loss regions. A simple parallel flow model, with appropriate physically-justified assumptions, can accurately predict this redistribution, and we demonstrate its effectiveness via comparison with CFD and experiment.
Influence of Shape and Size of Casting Defects on the LCF Performance of MAR-M247 – A Path Towards a Probabilistic Model
Authors: Radners Jan , Schweizer Christoph , Schlesinger Michael , Eckmann Stefan , Al-Ameri Malek , Amann Christian , Gumbsch Peter , Kadau Kai 
Published: August 2024

Abstract
Addressing anthropogenic climate change is a great challenge that requires integrating renewable energy resources into the grid. The intermittent nature of renewables creates a demand for more flexible gas turbine operation conditions. This increases the number of startup and shutdown cycles and leads to gas turbine components experiencing a significant increase in low cycle fatigue (LCF) loading. This study examines the LCF performance of a widely used rotor blade material to support flexible power plant operation. The study is part of a multi-year government-funded project developing a probabilistic fatigue lifetime model for cast material, including defects like cast porosity. The present work is the second contribution in an ongoing series of studies [1]. The focus of this work is the investigation of the influence of defect size and shape on LCF performance. Because defects introduce a variety of uncertainties, understanding their influence is required for developing a probabilistic approach. Additional model input parameters subject to uncertainties, such as grain sizes and orientations that significantly depend on blade location and design, are also investigated.
Biot Number Error in Low Temperature Inconel Overall Effectiveness Experiments
Authors: Hopkins Bailey W. , Hughes Jacob A. , Bryant Carol E. , Rutledge James L. 
Published: August 2024

Abstract
To predict the performance of turbine materials at engine conditions, experiments are often performed at lower temperature laboratory conditions. In order to ensure the low-temperature, laboratory results accurately predict the nondimensionalized surface temperature at engine conditions, several non-dimensional parameters must be matched in the experiment, including the Biot number. Matching the Biot number requires that the ratio of the thermal conductivity of the material to the thermal conductivity of the air must be matched between laboratory experiments and engine conditions. With traditional nickel alloys such as Inconel, it is sometimes assumed that the Biot number is matched since Inconel’s thermal conductivity variation with temperature scales relatively closely with that of air. However, the thermal conductivity ratio does not scale perfectly and therefore some Biot number error does indeed exist, with the problem exacerbated at lower testing temperatures. To date, there has been no experimentally verified quantification of the error in the overall effectiveness, ϕ, that might be caused by this Biot number error. Based on published thermal conductivity data, Ti-6Al-4V is predicted to allow for a better Biot number match, thereby better simulating Inconel at engine conditions in a typical low temperature experiment. In this research, we utilized geometrically identical models constructed of Ti-6Al-4V and Inconel 718 to evaluate the error in overall effectiveness that might occur through simply using an actual engine nickel alloy part at experimental conditions. While the Ti-6Al-4V model has a nearly perfectly matched Biot number, the Inconel model’s Biot number was 73% higher than appropriate. The overall effectiveness experiments were conducted at a range of advective capacity ratios and the overall effectiveness distributions were compared. The results demonstrate that ϕ measured in low temperature tests performed on an Inconel turbine component do not suffer markedly from Biot number error. The theoretically more Biot number appropriate Ti-6Al-4V model produced area averaged overall effectiveness values that differed by only 0.01 from its Inconel counterpart, within experimental uncertainty, and would only represent a roughly 10 K error in surface temperature prediction at engine conditions. These results suggest that typical nickel superalloys used in turbine components may be tested at low temperature without the use of a surrogate material to better match Biot number.
An Experimental Investigation of the Non-Axisymmetric Casing Treatment for a Low-Speed Axial-Flow Compressor Under Circumferential Inflow Distortion
Authors: Zhao Pan , Zhang Min , Li Yihan , Xu Xiaobin , Ba Dun , Du Juan 
Published: August 2024

Abstract
Aero-engine compressor often suffers from non-axisymmetric total pressure distorted inflow caused by S-duct or BLI inlets. Generally, the distorted inflow can reduce the stall margin (SM) of the compressor. In order to conquer this issue, casing treatment can be adopted for stall margin improvement (SMI). Considering that axisymmetric casing treatment always induces efficiency penalty, this paper conducted an experimental study on non-axisymmetric casing treatment (NACT) for a low-speed single-rotor axial compressor. Two type total pressure distortion inflow conditions including 30° and 60° annular range are involved. Also, various phase differences between NACT and distortion region are investigated. Experimental results indicate a 5.83% and 8.72% decrease in the compressor SM due to the two distorted inflow, respectively. At the near-stall point condition, the self-excited unsteadiness of tip leakage flow gradually intensifies after the rotor rotates into the distortion region, and it has a peak value at the exit of the distortion region where the first spike disturbance occurs. With the change in the phase difference, SMI obtained by NACT initially decreases, then increases, and finally exhibits a slight decrease. The maximum SMI values are 5.61% and 7.86% when the NACT extensively covers the exit of the distortion region for 30° and 60° distortion inflow conditions, respectively. Elaborate test of dynamic pressure and the wavelet analysis demonstrate that NACT can effectively suppress the initial stall disturbance with low-energy at the distortion region’s exit, preventing it from evolving into uncontrollable large-scale and high-energy stall cells. The analysis of the circumferential scale of stall inception indicates that the stall inception will occupy 7–8 blade passages after the application of NACT compared to SC of 2–4 blade passages under distorted inflow, which can provide some insights for future stall warning study.