bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental and Computational Investigation of an Advanced Casing Treatment in a Single Stage High Speed Compressor
Authors: Maher Nicholas H. , Ross Mark H. , Morris Scott C. , Priebe Stephan , Jothiprasad Giridhar , Allan David , McNulty G. Scott , Macrorie Michael 
Published: October 2022

Abstract
An advanced casing treatment design, in the form of bent-axial slots applied to the casing near the rotor leading edge, was tested in a single stage high speed axial compressor. Compressor performance and stall margin measurements were acquired for both casing treatment and for the smooth wall case at four different corrected speeds. The measurements also included rotor-exit radial traverses of unsteady total pressure. The results indicated an increase in rotor pressure ratio at all operating conditions with the application of the casing treatment. The stall margin also increased at all rotor speeds. Efficiency increases were observed with the casing treatment at design conditions and some off-design conditions.
Numerical simulations of the IGV, rotor, and stator were conducted with and without the casing treatment. These results served to validate the efficacy of the part-wheel Unsteady Reynolds-averaged Navier-Stokes (URANS) simulations to predict the effects of the casing treatment. The simulations also allowed a detailed study of the flow physics related to the interactions between the rotor and casing.
Residual Strength of Turbine Grade Ceramic Matrix Composites After Being Subjected to Solid Particle Erosion at Elevated Temperatures
Authors: Mirza Farhan , Panakarajupally Ragav P. , Morscher Gregory N. , Abdi Frank , Choi Sung 
Published: October 2022

Abstract
A preliminary study towards understanding the effects of elevated temperature hard particle erosion on remaining strength in ceramic matrix composites was initiated. Oxide and non-oxide ceramic matrix composites were subjected to erosion using alumina particles under a combustion environment at 800 and 1200°C. Eroded specimens were observed under optical microscopy capable of 3D depth scanning to understand the extent of erosion damage. The eroded specimens were then subject to room temperature tension test to evaluate the retained properties. The results indicate that erosion rate increases with an increase in particle velocity and temperature. Residual strength tests indicate that specimens impacted at higher velocity and temperature showed lower tensile strength due to increasing crater depth.
Characterization of Properties of Laser Powder Bed Fusion 3D-Printed Inconel 718 for Centrifugal Turbomachinery Applications
Authors: Lea Hannah G. , Wooding Rochelle S. , Kuhr Sam , Rotella John , Córdova José Luis 
Published: October 2022

Abstract
This paper presents the results of a comprehensive effort to characterize the properties of Inconel 718 produced by a form of laser powder bed fusion (LPBF) additive manufacturing (AM) or 3D-printing, subsequently subjected to hot isostatic pressing (HIP) and heat treatment according to standards F3055-14a and AMS 5663, respectively. Material property data, while broadly available for traditional Inconel 718 presentations (e.g. forgings or castings), is currently lacking for the 3D-printed material.
It is expected that while limited in size, the experimental data sets presented provide sufficient information to glean the capability of LPBF Inconel 718. These include: 1) Chemical composition, electron backscatter diffraction (EBSD), and x-ray energy dispersive spectroscopy (XEDS) characterization of 3D-printed material structure; 2) Tensile properties — 0.2% yield stress, ultimate stress, modulus of elasticity, and elongation to failure — based on 108 samples, as functions of temperature and sample print orientation; 3) Creep rupture data including the Larson-Miller parameter, based on 21 samples; and 4) High cycle fatigue data based on 21 samples as a function of temperature.
Results are compared to available standards and/or data for forged, cast, and other AM Inconel 718. A key observation of this study, based on the EBSD results, is that while the material appears to approach full recrystallization following heat treatment, there is a detectable fraction of the material that does not fully recrystallize, resulting in a material with mechanical properties (e.g. yield stress, creep rupture) measurably lower than those of forgings, but higher than those of castings.
Additive Manufacturing of Centrifugal Impellers for Solid Oxide Fuel Cell Anode Offgas Recycle Blowers
Authors: Córdova José Luis 
Published: October 2022

Abstract
A form of laser powder bed fusion (LPBF) 3D printing has been used to manufacture the impellers of anode offgas recycle blowers (AORBs) for solid oxide fuel cell (SOFC) applications. The material selected is Inconel 718, since it can endure the conditions and temperature ranges in which these systems typically operate. This paper presents details of the multiple process trials and the issues resolved to achieve a successful build, demonstrating the feasibility of the method for impeller manufacturing. Also discussed are the potential cost and design flexibility benefits that may be derived from 3D printing methods, particularly during integration of prototype and low count turbomachinery production runs. The paper discusses long-term goals of the project to support the reduction of cost of SOFC power plants by reducing the cost of balance of plant (BOP) subsystems, from design to integration.
Turbulence Characteristic and Loss of Transonic Turbine Tip Leakage Vortex With Endwall Motion Effect
Authors: Zhou Kai , Zhou Chao 
Published: October 2022

Abstract
Tip leakage flow is considered as an essential loss source within unshrouded high-pressure turbines. This work numerically investigated the flow physics associated with the prediction of the tip leakage loss in a transonic turbine cascade at a high Reynolds number. The instantaneous flow pattern predicted by delayed detached eddy simulation (DDES) shows that the dominating frequency of the tip leakage vortex from its initial generation to further downstream development varies slightly. However, with endwall motion, the scraping effect enhances the horseshoe vortex, and suppresses the tip leakage vortex within a smaller corner region. The dominating frequency of the tip leakage vortex varies significantly. After its breakdown, it spreads to a broad range of frequencies with much higher fluctuation velocity. This indicates that the evolution of tip leakage vortex in the endwall motion case is highly unstable, and anisotropic turbulence occurs. The Reynolds stress components are also investigated to show that vortex breakdown and turbulence characteristics. Besides, two typical Reynolds-averaged Navier-Stokes (RANS) models (Sparlat-Allmaras (SA) model and k-ω shear stress transport (SST) model) are applied to compare the ability in the prediction of the vortex patterns. The results show that in the stationary endwall case, the tip leakage loss is insensitive to turbulence model. However, in the endwall motion case, SST model overpredicts the loss while SA model underestimates the loss. Anisotropic turbulence makes the turbulence modeling cause an evident deviation in loss prediction. The loss prediction is relatively insensitive to the turbulence model in the stationary endwall case, while primarily sensitive in endwall motion case.
Negative Centering Forces of Wet-Gas Hole-Pattern Seals at Low Excitation Frequencies
Authors: Zhang Min , Childs Dara W. 
Published: October 2022

Abstract
Zhang and Childs (2021) investigated the behaviors of a hole-pattern seal (hole depth Hd = 1.9 mm) under wet-gas conditions. The hole-pattern seal’s rotordynamic coefficients were strongly frequency-dependent. Direct stiffness K increased as excitation frequency increased and was close to zero at low excitation frequencies. Cross-coupled damping c was negative and could reduce the seal’s net centering force. The net centering force can be represented by effective stiffness Keff. This paper calculates the Keff values of the seal presented by Zhang and Childs (2021) and finds that Keff decreases after adding oil to the air and changes from positive to negative in some cases. This paper also presents the test data for a new hole-pattern seal that has the same geometric dimensions except with a deeper Hd of 2.5 mm. Tests for the new seal are performed at 62.1 bars inlet pressure, 0.5 pressure ratio, three speeds from 10 to 20 krpm, and two inlet liquid volume fractions LVFs (zero and 2%). As Hd increases from 1.9 mm to 2.5 mm, Keff decreases, especially at low excitation frequencies. The new hole-pattern seal shows negative Keff values at low excitation frequencies. The negative Keff of the new hole-pattern seal at low excitation frequencies can lead to large negative centering forces and prevent testing for cases with inlet LVF higher than 2%. Predictions are produced by using San Andrés’s (2011) 2-phase bulk-flow model and compared with experimental results.
Numerical Investigations of Flow Structures in Radial Rim Seal and a Modification of the Orifice Model
Authors: Xue Qichao , Li Xueying , Ren Jing 
Published: October 2022

Abstract
Under the increasing turbine temperature of gas turbine, the thermal bearing capacity of rotor and stator of turbine is increasingly limited, which poses a more severe challenge to the protection means such as rim seal, and requires more detailed estimation of flow and heat transfer of rim seal. One of the most important parameters in the estimation is the sealing efficiency. The Orifice Model is widely used to simplify the prediction of sealing efficiency of various sealing structures. Its advantage is that different structures can be described by the same model. However, further work is needed in the prediction of sealing efficiency for more complex structures or the high radius of the locations such as the interface between the disc cavity and the main flow.
In this paper, steady numerical simulation is carried out for a radial rim seal structure, and the numerical results are verified by the experimental results in the disk cavity. The flow phenomenon and the mechanism of ingress flow near the rim seal structure is further studied. It is found that the ingress flow has axial and circumferential inhomogeneity, According to the tangential velocity, the ingress flow presents two distinct and “antagonistic” fluids respectively. On this basis, this paper proposes a modification to the Orifice Model, which determine whether the flow is egress or ingress by the tangential velocity. In addition, according to this method, the two-dimensional distribution of the egress and ingress at the interface near the main flow can be seen, and it can be fitted with a simple multi-segment linear function.
Effects of Pure Shearing and Rigid-Body Rotation on the Evolution of Tip Leakage Vortex in an Axial Compressor Rotor
Authors: Liu Yangwei , Zhong Weibo , Tang Yumeng 
Published: October 2022

Abstract
Tip leakage vortex (TLV) in an axial compressor has a considerable impact on aerodynamic performance. Hence, deeper insight should be gained into the evolution mechanism of the TLV. In this paper, the tip leakage flow (TLF) field of a low-speed large-scale axial compressor rotor at both design and near stall conditions by delayed detached eddy simulation (DDES) is analyzed. The swirling flow motion of the TLV is decomposed into three components: rigid-body rotation, pure shearing, and compressing-stretching. The effects of these swirling flow components on the evolution of TLV are investigated. Results show that the shearing and rotational motions of TLF at both design and near stall conditions vary because of the difference in leakage flow conditions. At the near stall condition, the TLV is stronger after its formation but breaks down earlier and changes more violently. Furthermore, the shearing effect plays a significant role in the TLF and prevails over the rigid-body rotation except in the core region of the stable vortex. Most of mechanical energy dissipation is caused by pure shearing. The spiraling pattern and orbital compactness of the TLV are investigated by the local trace criterion-based elliptical region (LTER) method. Results show that the main spiraling pattern of the TLV changes regularly as the TLV develops downstream. In addition, the decrease of the spiraling compactness level reflects the TLV breakdown due to the decrease of swirling strength caused by weaker rigid-body rotation and pure shearing. The swirling flow with high compactness caused by strong shearing effects contributes to the energy dissipation significantly.
Sintering Behaviour of 3d Printed 17-4PH Stainless Steel
Authors: Raju Nandhini , Warren Peter , Subramanian Ramesh , Ghosh Ranajay , Fernandez Erik , Raghavan Seetha , Kapat Jayanta 
Published: October 2022

Abstract
The main aim of the research work is to investigate the sintering behavior and its impact on the material properties of 3D printed 17-4PH stainless steel. The samples were manufactured by the Atomic Diffusion Additive Manufacturing technique, the Metal X system. Cooling holes were printed with the sample in different build orientations giving an overview of the printability and accuracy of the atomic diffusion additive manufacturing (ADAM) technique. Samples were processed by washing, thermal de-binding, and sintering to produce a final solid metal part. Pre-sintered parts, after washing, were tested for chemical composition, roughness, particle size analysis, density, Energy Dispersive X-ray spectroscopy, and microstructure analysis using Scanning electron microscopy (SEM) to understand the material properties. Post-sintered samples were tested for the same tests to understand the sintering impact. A unique conceptual approach and statistical analysis are included in this research. To understand the thermal de-binding and sintering kinetics Differential Scanning Calorimetry (DSC) and Dilatometry (DIL) tests were performed. DSC results gave details about the thermal de-binding and binder information. Dilatometry (DIL) results showed shrinkage over the temperature profile, and significant changes in shrinkages were found above 1250 °C. The results gave an overview of the sintering kinetics and sintering impact of 3D printed 17-4PH stainless steel. This helps decide the optimized thermal debinding and sintering profile to achieve high dense material. It should be noted that this is the first-ever study investigating in detail thermal de-binding and sintering kinetics and its impact on the material properties according to the ADAM technique.
Bearing Diagnostics Using Kurtosis Spectral Correlation Based on Cyclic Modulation Spectrum Estimation
Authors: Mauricio Alexandre , Gryllias Konstantinos 
Published: October 2022

Abstract
Bearings are critical machine components, thus monitoring of their health state is a key point in maintenance strategies for cost reduction and avoidance of unexpected breakdowns. Often, bearings’ signals remain masked below other dominant signatures and noise level. A common practice to enhance the signal to noise ratio of the transient signals due to bearing damages, is to filter around the carrier frequency of the transients and envelope the signal. A key issue is the correct detection of the carrier frequency of interest. This paper proposes a novel bi-frequency method, the Kurtosis Spectral Correlation. The method estimates the Spectral Correlation on the Spectral Kurtosis, instead of the classical Short Time Fourier Transform. This results in removal of the 1st order CS phenomena, while retaining the 2nd order CS impulsive signature in the frequency-frequency. The integration of the full band of the Kurtosis Spectral Correlation is proposed to extract the Kurtosis Enhanced Envelope Spectrum, as it provides a simpler bearing diagnostic tool compared to the analysis of the bi-frequency map. The effectiveness of the proposed method is demonstrated on simulated signals, and validated on an experimental drivetrain setup and on a wind turbine dataset.
A Stochastic and Bayesian Inference Toolchain for Uncertainty and Risk Quantification of Rare Autoignition Events in DLE Premixers
Authors: Yousefian Sajjad , Bourque Gilles , Jella Sandeep , Versailles Philippe , Monaghan Rory F. D. 
Published: October 2022

Abstract
Quantification of aleatoric uncertainties due to the inherent variabilities in operating conditions and fuel composition is essential for designing and improving premixers in dry low-emissions (DLE) combustion systems. Advanced stochastic simulation tools require a large number of evaluations in order to perform this type of uncertainty quantification (UQ) analysis. This task is computationally prohibitive using high-fidelity computational fluid dynamic (CFD) approaches such as large eddy simulation (LES). In this paper, we describe a novel and computationally-efficient toolchain for stochastic modelling using minimal input from LES, to perform uncertainty and risk quantification of a DLE system. More specially, high-fidelity LES, chemical reactor network (CRN) model, beta mixture model, Bayesian inference and sequential Monte Carlo (SMC) are integrated into the toolchain. The methodology is applied to a practical premixer of low-emission combustion system with dimethyl ether (DME)/methane-air mixtures to simulate autoignition events at different engine conditions. First, the benchmark premixer is simulated using a set of LESs for a methane/air mixture at elevated pressure and temperature conditions. A partitioning approach is employed to generate a set of deterministic chemical reactor network (CRN) models from LES results. These CRN models are then solved at the volume-average conditions and validated by LES results. A mixture modelling approach using the expectation-method of moment (EMM) is carried out to generate a set of beta mixture models and characterise uncertainties for LES-predicted temperature distributions. These beta mixture models and a normal distribution for DME volume fraction are used to simulate a set of stochastic CRN models. The Bayesian inference approach through Sequential Monte Carlo (SMC) method is then implemented on the results of temperature distributions from stochastic CRN models to simulate the probability of autoignition in the benchmark premixer. The results present a very satisfactory performance for the stochastic toolchain to compute the autoignition propensity for a few events with a particular combination of inlet temperature and DME volume fraction. Characterisation of these rare events is computationally prohibitive in the conventional deterministic methods such as high-fidelity LES.
Improvement of the Semi-Analytical Model of a Tesla Disc Turbine by the Correction of the Velocity Profile
Authors: Rusin Krzysztof , Hasani Malekshah Emad , Wróblewski Włodzimierz , Rulik Sebastian 
Published: October 2022

Abstract
The paper presents the results of investigations concerning a new analytical model of the flow between the two co-rotating discs. In the elaborated model, an emphasis is put on the different approaches to modelling the radial velocity profile. It was confirmed that its shape deviates from traditional parabolic curves, often assumed in the commonly used models, and is more of a “W-shape”, where the maximal velocity is reached at a certain distance from the wall rather than in the middle of the channel. The Buckingham-Π theorem is utilized to determine the factors influencing the radial velocity profile. Seven dimensionless terms were derived that include geometrical features (the channel height, radii), fluid properties (density, dynamic viscosity), thermodynamic parameters (pressure gradient) and kinematic quantities (tangential velocity, rotational speed). Computational fluid dynamics methods were employed to generate the results for various thermodynamic and geometrical conditions which were used as training data for the neural network to recreate the radial velocity profile. Utilizing Matlab software, the neural network was introduced to the popular analytical model of the flow between the rotating discs. The results prove better agreement with the validation data and also make it possible to assume pressure drop in the flow between the discs. The new model may improve the designing methods of the Tesla turbines as it offers higher precision of the performance prediction.
Detuning Optimization of Nonlinear Mistuned Bladed-Disks
Authors: Capiez-Lernout Evangéline , Soize Christian 
Published: October 2022

Abstract
One major industrial challenge is to consider the detuning as a technological means to reduce the dynamical amplifications induced by mistuning. Due to technological evolutions, the nonlinear geometrical effects induced by the large displacements cannot longer be neglected. Recently, methodologies for the robust analysis of detuned/mistuned bladed-disks in presence of geometrical nonlinearities have been developed. A full analysis of the detuning optimization of mistuned bladed-disks with finite displacements is carried out on a 12 bladed-disk finite element model. The paper is based on a computational methodology previously developed by the authors. It insists on the necessity to carefully optimize all the involved numerical parameters to get the nonlinear mistuned response of each considered detuned configuration with an optimal balance between response accuracy and computational costs. We then have to be very careful with the construction of an adapted scalar quantity of interest for defining the detuning optimization problem. Direct computations allowing for all possible detuned configurations to be considered allow for obtaining a full data basis. A meticulous post-processing shows the existence of a few detuned configurations, that inhibits the mistuning amplification effects of the pure mistuned bladed-disk.
Preliminary Analysis of High-Temperature Corrosion of Metallic Alloys With CO2 and CO2-Based Working Mixtures for Power Plants Applications
Authors: Putelli Lorenza , Di Marcoberardino Gioele , Gelfi Marcello , Invernizzi Costante Mario , Iora Paolo Giulio , Manzolini Giampaolo 
Published: October 2022

Abstract
CO2 has been proposed in the past decades as a suitable working fluid in power plants. One way to reduce costs is to use carbon dioxide blends instead. There is a lack of knowledge about the behavior of sCO2 blending in the interaction with commercial alloys at high temperatures, so this aspect must be strictly considered. A preliminary study has been performed considering the oxidation behavior of some Ni-based and Fe-based alloy (i.e., alloy 625, AISI 304, and AISI 316) in different conditions. In each case, the oxidation layer developed on the alloy surface was investigated by scanning electron microscope (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The analysis was also performed on the cross-section of the sample to evaluate the penetration depth of damage. The results show that the interaction with fluorine-containing compounds is more corrosive than pure CO2. This confirms that although the mixture improves the thermodynamic efficiency of the cycle, their compatibility with materials must be carefully investigated. However, in all the cases studied, in the test conditions, the preliminary analysis doesn’t recommend the use of the tested materials.