bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design Considerations for Directed-Lubrication Thrust Bearings Across a Wide Range of Operating Conditions With a Focus on Pressure Drop in the Oil Supply Path
Authors: Fabijonas Bruce R. , Krajewski Louis , Hegde Amruthkiran , Rodzwic Richard 
Published: August 2024

Abstract
Directed-lubrication bearings require careful control of the oil flow through the bearing to optimize performance. To do this, an accurate model of the pressure drop within the bearing is needed. This paper presents an equation-based model to compute the pressure drop and compares the model against test data and computational fluid dynamic simulations. We use this model to demonstrate the effects machining tolerances have on the pressure drop within a directed-lubrication thrust bearing. Finally, we discuss the current trend among OEMs to have a single bearing satisfy a range of operating conditions rather than an application specific condition and how this trend dramatically alters directed-lubrication bearing design philosophy.
Effect of Geometry and Heat Flux on Turbine Over-Tip Flow Power Extraction
Authors: Inhestern Lukas Benjamin , Peitsch Dieter , Paniagua Guillermo 
Published: August 2024

Abstract
The tip leakage flow is known to be a substantial loss contributor. A precise local loss decomposition of the relevant laminar and turbulent terms for viscous losses and thermal losses is required to predict the impact of tip design modification and revise current design guidelines. While losses due to viscous shear stress cause an irreversible reduction from the theoretical maximum power output, tip leakage vortices also penalize the flow turning. This paper combines a novel method for calculating volume-based loss terms and power extraction with an approach to track the tip leakage flow and to analyze the effect of heat transfer and varying tip gap height. Three different flow topologies were categorized for relative tip gap sizes between 0.23% and 1.10% passage height. The contribution of the tip leakage flow to the overall losses could be quantified at each streamwise location. The prime driver for efficiency improvements with tight clearance is achieved by a reduction in turbulent losses in the tip leakage vortices. Of secondary importance, but ubiquitous for all the tip gaps is the laminar loss, occurring in the overtip region and the main passage. The wall heat flux causes a massive effect on the aerothermal efficiency, the internal heat transfer increases exponentially with increasing wall heat flux.
Technology Readiness Assessment of Thermal Energy Storage Integrated With Gas Turbine Power Plants
Authors: Angello Leonard , Perullo Christopher , Widener Stanley , Booras George , Prescott Eric 
Published: August 2024

Abstract
This paper presents an integration readiness assessment for Thermal Energy Storage (TES) concepts. TES’s primary motivation is to store surplus energy and release it as needed to balance demand. Within the broader energy market, TES seeks to capture arbitrage opportunities and enable higher capacity factors for Variable Renewable Energy (VRE) sources like wind and solar. The paper explores how integrating energy storage with gas-turbine-based power plants can enhance value and capacity while reducing CO2 emissions. Both simple cycle and combined cycle plants are considered.
The paper carries out an Integration and System Readiness Assessment (ISRA) for three specific TES technologies: Brenmiller Crushed Rock, Pintail Power Liquid Salt Combined Cycle (LSCC), and Redox Box Thermochemical storage. The ISRA’s objective is to systematically evaluate the system readiness level (SRL) to determine the current development status and potential risks. Early identification of these risks can guide targeted demonstrations to mitigate risk and validate the technology. ISRA has been carried out for other systems but is being applied to the problem of the integration of new storage technology with existing generating assets with a desire to derisk technology showstoppers earlier in the maturation process. This paper demonstrates how this process can be used to focus technology development efforts on derisking activities vs. demonstration for demonstration’s sake.
Interviews were conducted with the technology developers to evaluate their current status, challenges, and successes. The focus is not solely on the score but on using the method to identify the technologies’ development stage. This paper specifically addresses readiness for integration into gas turbine power plants. Controls and balance of plant challenges when integrating into existing power plants were a common area for development.
Effect of Labyrinth Seal Parameters on Leakage and Rotordynamics in a Centrifugal Compressor Supported by Active Magnetic Bearings
Authors: Choudhury Tuhin , Ranjan Gyan , Smirnov Alexander , Heikkinen Janne , Rauhala Lauri , Sopanen Jussi 
Published: August 2024

Abstract
Centrifugal compressors will play a key role in efficiency of energy transition from fossil fuels in commercial and district heating applications. The overall efficiency of such compressors can be further improved by incorporating active magnetic bearings and high-speed direct drives, especially in high temperature, high-capacity heat pumps. However, at high speeds, the sealing of the refrigerants can present several challenges related to leakage and rotordynamic instability. Typically, hermetically sealed compressor design provides a simple, cost-effective solution with radial or axial labyrinth seals to separate compressor stages from the motor components and bearings. However, significant leakage from labyrinth seals could have adverse effect on magnetic bearings, such as cooling loss, contamination and imbalance. Moreover, asymmetric pressure distribution across impeller back plate or shaft surface can often lead to large cross coupling dynamic coefficients, thereby increasing the chances of instability during operation. To that end, this paper investigates how different seal parameters affect the leakage and rotordynamics in a single stage compressor. For both axial and radial labyrinth seals, the study presents the correlation between seal parameters and leakage. Lastly, a rotordynamic model is developed for the rotor -magnetic bearing system, including the dynamic coefficients of the seals and the impeller, and any possible instability are investigated.
Damage to a High Bypass Ratio Fan During UAS Ingestions
Authors: D’Souza Kiran , Sirivolu Dushyanth , Gomez Luis , Olivares Gerardo 
Published: August 2024

Abstract
Foreign object ingestion into engines has been studied for many years, but the focus has been on soft bodies (i.e., birds, ice). Recently, there has been a dramatic increase of uncrewed aircraft systems (UAS) in the airspace that represent a new threat to aircraft engines due to key components like the motor, battery, and camera being composed of hard components. Due to the differences between hard bodies and soft bodies, studies are required to understand the new threat these UAS pose to aircraft. The objective of this study is to investigate the impact of various factors such as impact orientation, fan rotational speed, relative translational speed, and radial impact location on the damage caused to a representative fan assembly. This study aims to analyze the sensitivity of these factors and their influence on the overall damage to the fan. The ingestion simulations will use a representative fan assembly model and a UAS model that has been experimentally validated at the conditions of an ingestion. This work will identify critical parameters of the ingestion and then utilize them to anticipate the extent of damage that may arise during specific stages of a flight where an ingestion is most probable. Moreover, it also compares these cases with some known baseline cases, such as a fan blade out and bird ingestion of similar mass, to understand the likely severity compared to more studied common cases.
How Frictional Heat Affects the Performance of Underplatform Dampers: Interface Temperature and Dynamic Behaviors
Authors: Gao Qian , Fan Yu , Zucca Stefano , Wu Yaguang , Li Lin 
Published: August 2024

Abstract
Underplatform dampers (UPDs) not only dissipate vibration energy of turbine blades, but also generate substantial frictional heat. The heat may potentially elevate the interface temperature beyond the melting point. Moreover, the increased interface temperature can alter the friction coefficient and contact normal force, significantly affecting the damping performance of UPDs. Consequently, the blade dynamics are highly coupled with frictional thermal effect. The interface temperature and corresponding dynamic behaviors (e.g. forced response, nonlinear mode) should be assessed considering the effect of frictional heat. In this paper, we develop a multi-physics model of turbine blades with UPDs, which integrates the contact nonlinearity and frictional heat transfer. The thermomechanical contact constitutive relationship is modeled at the contact interface. Two numerical methods are improved and utilized: Dry Friction Thermo-Mechanical Coupling Response Prediction (DFTMCP) and Thermo-Mechanical damped Nonlinear Normal Mode (TM-dNNM). DFTMCP predicts the interface temperature rise and nonlinear forced response, while TM-dNNM facilitates the identification of nonlinear modal characteristics and predicts the detailed temperature distribution. Results indicate quantitatively that frictional heat has a significant effect on the interface temperature and damping performance of UPD.
Effects of Lattice Orientation Angle on TPMS-Based Transpiration Cooling
Authors: Son Juchan , Broumand Mohsen , Pyo Yeongmin , Richer Patrick , Jodoin Bertrand , Hong Zekai 
Published: August 2024

Abstract
Establishing a continuous cooling film is an effective way to thermally protect hot-gas path components of gas turbines. For aero-engines, effusion cooling is the state-of-the-art method for developing cooling films. However, the cooling film generated by this method is far from ideal, as discrete miniature cooling air jets exiting from effusion cooling holes leave large gaps between cooling holes without adequate cooling film protection. Furthermore, effusion cooling jets can experience strong lift-off from component surfaces and are subsequently diluted due to mixing with the main flow. Recent advances in additive manufacturing (AM) technologies have enabled the fabrication of porous materials with precisely engineered lattice structures, significantly enhancing the film cooling effectiveness of hot-gas path components through transpiration cooling. A prior study has demonstrated highly promising transpiration cooling results by using a family of lattice geometries referred to as triply periodic minimal surface (TPMS) lattices. The present study experimentally investigates the influence of various TPMS lattice orientations on the film cooling effectiveness. Three types of TPMS structures, namely Diamond, Koch and Gyroid, are compared to demonstrate that the TPMS lattice orientation angle affects transpiration cooling performance, with different levels of sensitivity according to the TPMS structure. The TPMS lattice structures studied in this investigation are fabricated by stereolithography (SLA) 3D printing. The adiabatic cooling film effectiveness (AFE) is measured using pressure sensitive paint (PSP).
A Wind Speed Forecasting Method Using a Gaussian Process Regression Model Considering Data Uncertainty
Authors: Chen Huize , Jiang Xiaomo , Hui Huaiyu , Zhang Kexin 
Published: August 2024

Abstract
Wind speed forecasting has become an essential part of power forecasting, daily operation, and optimal scheduling of wind farms. However, due to the extreme randomness and unpredictability of wind resources, it’s still a very challenging task to accurately forecast wind speed considering data uncertainties. Most existing methods do not take into account the data uncertainty and randomness in wind speed forecasting, resulting in inaccurate results in practical applications. This paper proposes a hybrid intelligent model for wind speed forecasting under uncertainties by adeptly integrating Bayesian Discrete Wavelet Packet Transform (BDWPT) and Gaussian Process Regression (GPR). Firstly, the BDWPT method is applied to reduce the noise and randomness of raw data by taking advantage of its powerful adaptive denoising capability. Then, the GPR model is developed to model the randomness in wind speed forecasting. Finally, a comparison study with traditional methods by using the data collected from real-world wind farms is conducted to show the advantages of the proposed methodology in terms of one-step and multi-step cases. This study provides a promising approach to accurately forecast wind speed for turbine design and power management considering data uncertainties.
Preliminary Characterization of the Desolination Project Demo Plant: Design and Off-Design Operability
Authors: Morosini Ettore , Astolfi Marco , Doninelli Michele , Iora Paolo , Serret Damien , Hugo Jean-Michel , Manzolini Giampaolo 
Published: August 2024

Abstract
This work presents the preliminary performance of the simple recuperative transcritical power cycle of the DESOLINATION project demo plant. The cycle operates with the CO2+SO2 mixture and it is air-cooled, built in a CSP-like environment with high radiation and high ambient temperature. The axial turbine, with a flowrate of 0.2 m3/s at its inlet, imposes the size of the cycle at 1.8 MWel. Innovative recuperators and primary heat exchangers with internal gyroid structures are adopted, modelled with a simplified approach in MATLAB by fitting results of CFD simulations. By modelling the cycle offdesign in sliding pressure, cycle efficiencies above 30% can be obtained, even at part load. Fixing a high ambient temperature at design conditions, the cycle cannot operate with ambient temperatures below 30°C if the condenser fans work at fixed speed, whereas ambient temperatures of 10°C are possible modifying the air velocity. By preliminary sizing the system piping, it is determined that the overall cycle inventory depends only on the conditions in the condenser, determined by the ambient temperature. Accordingly, an inventory variation of around 300 kg must be handled to correctly operate in offdesign.
Influence of Baseplate Flexibility in Rotordynamic Analysis of Rotating Equipment
Authors: D’Addio Vincenzo , Gorgeri Alessio , Libraschi Mirko , Capanni Francesco 
Published: August 2024

Abstract
The aim of this study is to show how baseplate flexibility can be included in the rotodynamic analysis in an efficient yet accurate manner. Baseplate modal information is added into the classical rotodynamic system (rotor + bearings) using a proper modal condensation method. On the one hand, the relatively complex shape of the baseplate requires 3D modelling strategies, while rotodynamic analysis is normally conducted using 1D beam elements. The mono-dimensional approach is motivated by the axial symmetricity of the rotor, and it facilitates sensitivity analyses related to the microgeometry uncertainty of the fluid film bearing. The use of 1D approaches in rotodynamic is still a highly debated argument, especially due to the recent improvements of computer performance and the consequently increased viability of high-fidelity models. Nevertheless, the time consumption is not the only (nor most important) advantage of 1D approaches: a low fidelity model is better comparable to, and is more easily calibrated with, experimental test data (3D high fidelity models are often not verifiable by observations). There are several ways to include the baseplate dynamics on the rotodynamic system and in this paper three methods of representation will be presented and compared: State Space Matrices (SSM), Frequency Response Function (FRF) and Dynamic Stiffness & Damping Method (DSM).
Probabilistic Modelling Geometric Tolerance and LCF Life of Gas Turbine Compressor Blade
Authors: Meng Zhiqiang (David) , Bluck Richard , Sjödin Björn 
Published: August 2024

Abstract
This paper presents a probabilistic LCF assessment for geometric tolerances on high load contact surfaces of gas turbine compressor blades. The typical patterns of the geometric deviations for the root contact flank of the compressor blades are identified and characterized according to CMM measurements of the blade root. These typical patterns are closely related to the root form manufacture tools and process.
FE models for the typical geometric deviation patterns are created based on nodal coordinates transformation of the surface nodes on the blade root contact flanks and radius. An optimized blade root profile tolerance is established, which enables significant cost saving. The elastic-plastic FE analysis with nonlinear contact model, material strain-life test, response surface and constrained Monte Carlo simulation are used to create a probabilistic LCF life model for the optimized tolerance. The model quantifies the effect of the geometric deviations, blade mass and material property on the blade LCF life.
The result shows that with the optimized tolerance, the probability of blade LCF failure is very low and acceptable. It is also shown that the strain life material property is the most critical factor for the LCF failure. The root profile tolerance and blade mass are seen to have a much weaker effect on the blade LCF life.
Effect of Head-End Fuel Staging on Combustion Characteristics in a Multi-Nozzle Array Combustor
Authors: Liu Zhigang , Wei Xiaopo , Xiong Yan , Lu Xinggang , Zhang Zhedian , Zhang Shijie , Xu Xiang 
Published: August 2024

Abstract
Due to the need for enhanced gas turbine efficiency, the outlet temperature of the combustion chamber is increasing. Micromixed combustion (MMC) technology has been widely adopted in gas turbine combustion chambers to achieve low NOx emissions. In order to improve the performance of load regulation and inhibit thermoacoustic oscillations, this study investigates the effect of head-end fuel staging on the combustion characteristics of a multi-nozzle array model combustor through numerical simulations and experiments. The results demonstrate that employing different nozzle spacings effectively enables stable combustion. When only the pilot nozzle is operational, ignition stability is ensured by local flue gas recirculation zones from unit nozzles, as well as a large recirculation zone at the center of the combustion chamber. However, when both pilot and main nozzles are operational, expansion effects caused by high-temperature flue gas compress the central large recirculation zone. There is no significant impact on local flue gas recirculation zones between the pilot unit nozzles. The fluid dynamics within the model combustor guarantee its combustion stability and uniformity in outlet temperature under rated load conditions. NOx emissions are controlled through localized flue gas recirculation and flame lift-off mechanisms, which reduce the maximum temperature within the combustion chamber. The NOx emissions from this model combustor were found to be less than 25 ppm @15%O2.
Development and Characterization of EB-PVD Thermal Barrier Coatings With Different Ceramic Materials for Turbine Blades
Authors: Korkmaz Hanifi Eray , Güven Gökhan , Dikbıyık Alican , Yücesan Güven , Kazmanlı Kürşat 
Published: August 2024

Abstract
Thermal barrier coatings (TBC) are expected to exhibit specific properties, including low thermal conductivity, high thermal expansion capabilities, and excellent resistance to corrosion. Presently, yttria-stabilized zirconia (YSZ) is the prevailing choice for thermal barrier coatings, owing to its low thermal conductivity (approximately 1.5 W/m.K) and superior thermal shock resistance. YSZ can effectively insulate components at temperatures of around 1400°C and is also compatible with various ceramic materials, including Gd2Zr2O7, Nd2Zr2O7, Sm2Zr2O7, and La2Zr2O7.
Enhancements to thermal barrier coatings offer the promise of increased efficiency in gas turbine engines, as well as the extension of the service life of high-cost materials. In pursuit of these objectives, this research initiative primarily focused on the production of diverse ceramic materials, namely 7YSZ, Gd2Zr2O7, Sm2Zr2O7, Nd2Zr2O7, and 4Gd2O3 + 4Y2O3SZ coating materials, characterized by optimized production parameters. These materials were synthesized from their oxide forms utilizing the solid-state method. To facilitate the adhesion of these coatings to the CMSX-4 superalloy substrate materials, a bond coat consisting of Pt-NiAl was applied using the pack cementation and VPA (Vapor Phase Aluminizing) methods. Subsequently, the synthesized ceramic materials were deposited onto the CMSX-4 superalloy substrates through the Electron Beam-Physical Vapor Deposition (EB-PVD) technique. Comprehensive characterizations were then conducted on these coating structures.
Following the coating processes, scanning electron microscopy (SEM) analysis was conducted to evaluate coating thickness and morphology. Additionally, thermal conductivity, scratch resistance, and hardness tests were performed on the coated samples.
Effects of the Blade Tip Loading Distribution on Transonic Centrifugal Impeller Stability
Authors: Yang Bijie , Cao Teng , Hayashi Yoshihiro , Kanzaka Tadashi , Tomita Isao 
Published: August 2024

Abstract
Blade loading distribution is a crucial parameter for a compressor design. This study investigates the impact of the blade tip loading on transonic centrifugal impeller stability, comparing front-loaded and rear-loaded impeller designs through full annulus URANS simulations. Key findings reveal that the overall stability of the compressor relies on the interaction between inducer and exducer behaviors. The front-loaded design strategically shifts the inducer’s instability point to a higher volume flow rate where the exducer is more stable. It helps enhance the overall impeller stability but at the cost of efficiency. This is because different blade loading designs influence workload distribution within the inducer and exducer. The front-loaded design imposes higher inducer loading with early work input rollover and increased losses. This design better shapes its pressure-rise characteristics and extends stability, albeit with efficiency trade-offs. Detailed flow analysis shows that the front-loaded design intensifies tip-leakage flow, accelerating interactions and leading to earlier leading edge flow spillover. In contrast, the rear-loaded design displays a more stable tip-leakage flow, delaying the spillover and inducing early overall pressure-rise drop when the exducer’s stability is weakened. However, both designs converge in flow fields and performance characteristics when significant reverse tip flow occurs at low flow conditions.
A Computational Study of Temperature Driven Low Engine Order Forced Response in High Pressure Turbines
Authors: Trafford Alexander , Stapelfeldt Sina 
Published: August 2024

Abstract
This paper reports the results of computational studies of the effect of combustor exit temperature distortions on Low Engine Order (LEO) forced response of a High Pressure Turbine (HPT). Forced response of this kind occurs at frequencies below the Stator Vane Passing Frequency (SVPF) and can be a major cause of High Cycle Fatigue (HCF) in turbines due to its tendency to excite fundamental modes of vibration. This paper investigates the extent through which temperature distortions act as a forcing stimulus in HPT rotor rows, through measuring unsteady pressure and modal force magnitude recorded from full annulus unsteady simulations of the MT1 stage: a low temperature, unshrouded, HPT rig. Rotor relative incidence angle variations are shown to be the key mechanism through which temperature acts as a forcer in HPT rotor rows, whilst temperature driven forced response is shown to be dependent on the magnitude of the modal content of the upstream temperature waves. These findings are used to build a reduced domain tool for blocked burner forced response prediction, which is shown to be accurate to an RMS error of 2.66%, far beyond the current accepted standard for forcing prediction of this kind.