bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heavy Duty H2 Gas Turbine Demonstration – A Combined Experience
Authors: Demougeot Nicolas , Bullard Timothy , Kalb Bryan , Hernandez Fred , Spalding Martin , Yaquinto Matt , Soffritti Gabriele , van den Hout Franklin , Lee Dong Ki , Hwang Jun Won 
Published: August 2024

Abstract
Renewable energy sources are developing rapidly worldwide. The inherent intermittency of those is leading the electrical industry into finding alternate energy storage solutions and Hydrogen, a Carbon free fuel, is a prime candidate. South Korea is aspiring at being a World Leader in decarbonization of its energy sector and currently developing a dedicated, Carbon free, market.
Low pollutant Hydrogen combustion is notoriously difficult to achieve, low NOx in particular. Most OEMs are developing premix combustors but hurdles are numerous, adequate flashback margin being the biggest issue. PSM’s FlameSheet™ combustor was proven numerous times in various test rigs above the 80%vol H2 mark, but also in engines up to 25%vol H2. Full scale demonstration above 50%vol H2 in an engine was next.
PSM, Thomassen and Hanwha joined forces to move, convert and commission a 7EA capable of burning in excess of 50%vol H2. The site is located in the West of Korea, in a petro-chemical plant. Off-gas containing up to 40%vol H2 was used together with pure H2, and Liquified Natural Gas for start-up. A mixing station was designed to combine those three streams and precisely control a level of H2 in the mixture fueling the engine.
This paper will highlight the challenges faced and the solutions devised for the combustor, the fuel delivery system and the control sequences. Those were some of the key elements to success.
Safety was another important aspect and key principles will be described while an overview of the project will also be discussed.
After months of efforts including three months of commissioning, the GT achieved full load on April 14th, 2023. An official governmental measurement of 59.5%vol H2 and single digit NOx was demonstrated. The upcoming efforts will be briefly discussed.
Effect of Turning Vane on Tip Wall Heat Transfer in a Rotating Two-Pass Rectangular Channel
Authors: Huang Szu-Chi , Chia Kai-Chieh , Yeh Je-Wei , Liu Yao-Hsien 
Published: August 2024

Abstract
During gas turbine operation, the blade tip region experiences high thermal load. Adequate cooling near the tip is necessary to reduce thermal stresses and extend blade lifespan. This study examined heat transfer distribution on the tip wall of internal cooling channels through experimental measurement and numerical simulation. A two-pass rectangular channel with an aspect ratio (AR) of 1:4 and a hydraulic diameter of 25.6 mm was used. In the 180° turn region, both full turning vanes and slotted turning vanes were installed to minimize pressure loss while maintaining favorable heat transfer distribution. Thermochromic liquid crystals thermography and stroboscopic photography were employed in the experiment to obtain heat transfer distribution on the tip wall. The Reynolds number ranged from 10,000 to 30,000, while the rotation number ranged from 0 to 0.53. To increase rotation number, internal channel pressure was increased while keeping Reynolds number constant in order to decrease flow velocity. In the numerical study, ANSYS-Fluent R19.2 software was used for predicting flow field using a transition SST turbulence model with air as working fluid. The slotted turning vanes allowed flow impingement on the tip wall resulting in a higher heat transfer rate compared to cases with full turning vanes (10% higher). Both cases with turning vanes showed lower pressure drop and reduced heat transfer magnitude compared to smooth cases without turning vanes. Generally, rotation had less effect on tip wall heat transfer for cases with turning vanes due to reduction of rotation-induced secondary flow by these vane structures. The effect of channel orientation was less significant for cases with turning vanes compared to those without them.
Impact of Off-Design Performance of Turbines on Organic-Rankine Cycle Simulations for Solar-Power Applications
Authors: Yildirim Erdal , aus der Wiesche Stefan , Azmi Aktacir Mehmet 
Published: August 2024

Abstract
Organic Rankine Cycle (ORC) power systems offer a high potential for utilizing solar power for electricity generation. Inherently, the heat supply by solar power is time-dependent, and significant fluctuations occur during the day. Although some time-averaging of the heat input by thermal storage systems might be employed, the off-design performance of turbines is highly relevant for the mean thermal efficiency of such cycles. This study aims to analyze the effect of a hybrid power plant system obtained by combining an Organic Rankine Cycle (ORC) and a Linear Fresnel system (LFR) on the ORC turbine efficiency under part-load. The performance data of the LFR system is taken from an installed system designed to produce 20 kW of heat. The LFR-ORC system was modeled in detail, and thermodynamic calculations were performed using the cycle simulation program EBSILON. The local Direct Normal Irradiation (DNI) values for the selected day, the thermal efficiency of the system, and the temperature and mass flow rate of the thermal oil entering the system were used as inputs for ORC cycle. The ORC power plant was designed as a subcritical cycle with Novec 649 as the working fluid. The off-design performance of the ORC turbine used is compared with the nominal design operating performance using the Kroon and Tobiasz approach. The turbine efficiency as a function of the part-load operation was discussed within the framework of selected loss correlation. The analysis examined the thermal efficiency obtained from the turbine on the ORC side for varying thermal efficiency on the solar field side.
Aerodynamic Design Methodology for High-Load Compressor Blade Profiles at Low Reynolds Numbers
Authors: Xu Huafeng , Wang Mingyang , Zhao Shengfeng , Sheng Xiaoying , Lu Xingen 
Published: August 2024

Abstract
This study presents a novel design methodology that integrates design, experimentation, and computational fluid dynamics (CFD) to tackle the aerodynamic challenges of high loads and low Reynolds numbers (Re) in high-altitude, long-endurance unmanned aerial vehicle (UAV) engines. By applying high-speed experiments at low Re and large eddy simulation, a comprehensive database for high-load compressor cascades was constructed, covering Mach numbers from 0.4 to 0.7 and Re from 0.8 × 105 to 2.5 × 105. The fundamental strategy involves managing the pressure peak at the blade’s leading edge and load distribution. Precise velocity control at the leading edge and strategic load distribution optimization facilitate flow transition, inhibit separation bubble formation, and ensure blade aerodynamic efficiency and stability. Using this method, the article redesigns the rotor and stator blade profiles for a specific high-load booster stage. The design of the original rotor and stator blades was initially based on traditional methods and optimized using algorithms. The effectiveness of the methodology was validated through the integration of experimental data and extensive CFD analysis. Results demonstrate that this technique ensures excellent aerodynamic performance for high-load compressor blades under low Re and complex flow conditions. The findings significantly advance technological innovation, enhancing performance, endurance, and mission adaptability in high-altitude, long-endurance UAVs.
A Parallel Online Performance Optimization Method for ATR Engines Based on Ensemble Neural Network
Authors: Cai Weidong , Zhao Wei , Liu Binbin , Yang Xuesen , Luo Weiwei , Zhao Qingjun 
Published: August 2024

Abstract
To address the issue of lengthy optimization processes for ATR engines using swarm intelligence optimization algorithms such as Particle Swarm Optimization (PSO) and Genetic Algorithm (GA), a novel Ensemble Neural Networks based Parallel Performance Optimization (ENNPPO) methodology is proposed. This strategy amalgamates several small neural networks into a comprehensive larger model for the construction of an advanced onboard ATR engine model, moreover, the independence of each small neural networks allows for the reduction of computational time through parallel processing on GPUs. The method then harnesses the PSO algorithm to refine performance. Numerical simulations carried out with embedded GPU computing chips demonstrate that the average optimization time per test case is 0.28 seconds, with an energy consumption of 1.22 Joules. The proposed method achieves an optimization precision that is 78.40% and 84.30% higher than that of traditional neural network approaches and Linear Parameter-Varying (LPV) model methods, respectively. Furthermore, the computation speed is enhanced by a factor of at least 7.8 times than CPU, directly attributable to the expedited parallel processing enabled by GPUs.
Aerodynamic Characterization of an Industrial Inlet Particle Separator for Turboshaft and Turboprop Engines
Authors: Sanapo Carlo , Castaldi Marco , Mayo Yague Ignacio , Demolis Jacques , Eulitz Frank 
Published: August 2024

Abstract
Inlet Particle Separators (IPS) can be installed at the intake of turboprop and turboshaft engines as filtering protections, ensuring improved performance and operational stability in challenging environments. To validate and characterize novel IPS designs, it is essential to assess their performance before integrating them into the aircraft powerplant. In this paper, we aim at providing the experimental and numerical characterization of an IPS designed for industrial applications, defining a methodological approach that can be applied to similar test cases, as well as for training reduced order models. A comprehensive test campaign was undertaken at the von Karman Institute to analyze the pressure loss and separation efficiency of the IPS within an innovative test rig. This facility enables the exploration of different geometrical configurations and IPS flow regimes, mirroring real-world application and environmental conditions. The investigation mainly focused on parameters such as Reynolds number, bypass ratio and Stokes number. Both steady and unsteady Computational Fluid Dynamics (CFD) simulations with Lagrangian particle tracking were also performed, with two levels of resolution (based on the grid size), to gain more insights on the flow and particle trajectories inside the channels, and to complement the experimental findings. The reliability of the numerical tools is validated by comparing the CFD results with the experimental data. The authors specifically discuss on the discrepancies between the numerical and experimental outcomes in certain flow configurations, reasoning on the uncertainty analysis of the experimental data, and on potential deficiencies of the chosen CFD models.
Experimental and Numerical Investigation of NH3/H2/N2 Combustion in a Premixed/Stratified Swirl Burner
Authors: Davies Jordan , Mazzotta Luca , Sato Daisuke , Mashruk Syed , Pugh Daniel , Borello Domenico , Valera Medina Agustin 
Published: August 2024

Abstract
Interest in using renewably produced, partially cracked ammonia in gas turbines is gaining traction, but challenges relating to emissions of NOx and unburned ammonia remain. The present work progresses existing research on using hydrogen stratification to reduce NOx from ammonia/hydrogen flames by experimentally and numerically investigating the effects of also injecting nitrogen from the cracking process. It additionally assesses the NOx reduction capability of a recently developed novel swirl burner by adding hydrogen to the stratified flow to maintain the diffusive equivalence ratio at two high NO production conditions, slightly lean and stoichiometric.
At slightly globally rich conditions, maintaining the diffusive equivalence ratio at 0.9 resulted in an order of magnitude reduction in NO emissions with only a 33% increase in unburned NH3, compared to a fully premixed flame with the same fuel and air flow rates. This stratified configuration was found to increase consumption of NO by NH2, likely due to flame morphology effects, while NO production from OH and HNO pathways was reduced. The reduced OH intensity was posited as the cause for increased NH3 emission. A strong emissions sensitivity to diffusive equivalence ratio was found, as the case with a stoichiometric diffusive equivalence ratio did not show such marked improvements over its corresponding premixed condition. Both stratified and premixed flames were found to be stable, however stratification has potential to trigger instabilities at different frequencies to premixed.
Flow and Heat Transfer Characteristics in a Rotating Wedge-Shaped Cooling Channel With Detached Guiding Pin-Fin
Authors: Chen Jianian , Rao Yu , Xu Chao , Yang Li 
Published: August 2024

Abstract
Experiments and numerical simulations are conducted to investigate the flow and heat transfer characteristics of the guiding pin-fin array in a rotating wedge-shaped channel that represents the internal cooling passage features for turbine blade trailing edges. The rotating experiments cover Reynolds number ranges from 10,000 to 80,000 and rotation number ranges from 0 to 0.46. The results demonstrate that, with a proper arrangement, the guiding pin-fin array can significantly reduce the endwall temperature and pressure loss in the wedge-shaped channel. However, it was observed that at the mid-span of the guiding pin-fin array channel, heat transfer was relatively low, forming a high-temperature region. To enhance channel heat transfer uniformity, 2 mm clearances were introduced to the guiding pin fins at the channel root region, 2 mm from the trailing endwall. The numerical results show that this structural modification effectively improved the endwall heat transfer intensity at the mid-span of the wedge-shaped channel, particularly on the leading surface. In cases with Reynolds number (Re) equal to 50,000 and rotation number (Ro) equal to 0.075, the leading and trailing endwall Nusselt numbers of the detached guiding pin-fin array were 6.5% and 4.8% higher than those of the guiding pin-fin array. The secondary flow and transverse vortex induced by the detached pin fins reduced the main stream velocity, thereby inhibiting the Coriolis force effect and diminishing the endwall heat transfer discrepancy. Further comparisons at Re = 50,000 and Ro = 0.075 and 0.15 revealed that the leading and trailing endwall heat transfer discrepancy coefficient (δ) of the detached guiding pin-fin array was 61.8% and 42.2% lower than that of the circular pin-fin array, respectively.
LCA Modelling of Forged Components for Turbomachinery: Improved Approach Based on Production Data
Authors: Al Freijat Mosè , Orlandi Rachele , Ragni Giacomo , Pucciarelli Martina , Serra Angela , Fantozzi Francesco 
Published: August 2024

Abstract
Life Cycle Assessment (LCA) is a well-defined methodology employed to evaluate environmental impacts along the life cycle of products and services. Even if the methodology is standardized, its applicability relies on the availability of representative inventory data. Utilization of LCA in the turbomachinery sector is recent, therefore the lack of representative processes of this sector in commercial databases. Commercial databases provide generic processes, not always representative of the turbomachinery industry processes, which may increase the uncertainty of the LCA results and provide low accuracy. An example is the forging process, which is employed to manufacture most turbomachinery components, due to high material properties requirements. The forging process strictly depends on geometry, material, and size of component to be produced. Ideally, for each forged item, primary data would be collected to create and inventory and an LCA model. The data collection but would require a huge effort in terms of time by the forging industry and the LCA practitioner. Up to now, the lack of primary data on the specific processes has been overcome by leveraging on company validated information. This article presents an approach to overcome the lack of primary data to be used to model the forging process of semi-finished components considering all the processes required for its production. A simplified model has been developed, based on validated databases and Baker Hughes’supply chain real data. This model allows a quick and more accurate estimation of the environmental impact in terms of Carbon Footprint (CF) of forging process with a lower uncertainty compared to commercial database.
Investigation of Grooved Front Plate for Inlet Swirl Reduction in Brush Seals
Authors: Abbas Abdullah M. , Pekris Michael J. , Chew John W. 
Published: August 2024

Abstract
Brush seals are plausible replacements for conventional labyrinth seals in gas turbines for managing internal air system flows and leakages. They can offer superior leakage performance compared to labyrinth seals due to their compliant nature, and a reduced effective clearance during operation. Despite their improved sealing performance, highly swirling flow and aerodynamic forces on the upstream bristles could lead to aero-elastic instability within the bristle pack. This study investigates grooves as a means of improving brush seal robustness in high-shaft speed locations by reducing the inlet swirl that is incident on the bristle pack. The material removed and implied manufacturing effort and cost are considered. A parametric study of a simple groove geometry was conducted using CFD and a porous medium representation of the bristle pack whose resistance coefficients were calibrated to Bayley and Long’s data to achieve representative seal leakages. This identified groove length, width, angle and pitch as the important groove parameters for swirl reduction and demonstrated that the performance of ribs from previous research can be replicated and improved upon. A Design of Experiments (DOE) approach was adopted to investigate a novel groove design geometry. Combining a horizontal channel with an inclined groove enables a higher pitch to achieve the same swirl reduction by increasing drag and exploiting fluidic effects. The results indicate that the novel groove design performs as intended in substantially reducing the swirl incident on the bristle pack. Adding these features to the traditional front plate may improve brush seal robustness by reducing the effect of aerodynamic forces which could drive bristle pack instabilities, thus having the potential to aid their deployment in high-radius or high-shaft speed engine locations.
Investigation of Conjugate Heat Transfer in Wall-Modeled Large Eddy Simulation of High-Speed Compressible Wall-Bounded Flows
Authors: Muller Julia A. , Dutta Meghna , Boisvert Joshua , Oefelein Joseph C. 
Published: August 2024

Abstract
A parameter study is performed in a compressible boundary-layer at supersonic conditions to investigate the accuracy of a validated loosely-coupled Conjugate Heat Transfer (CHT) model combined with an advanced wall model approach for Large Eddy Simulation (LES). Fully-coupled CHT typically introduces extreme additional cost to numerical simulations due to large time-scale disparities between processes in the fluid and solid domains. Loosely-coupled CHT methods seek to mitigate this cost while simultaneously maintaining the correct boundary layer dynamics and local heat transfer processes. Likewise, wall-modeling makes LES more computationally tractable, but has not been widely used with CHT. The current investigation demonstrates the performance (accuracy and computational cost) of these approaches when implemented as a unified model. Results demonstrate that the selected wall-modeled LES, combined with a fully-integrated loosely-coupled CHT model, can reproduce the accuracy of reference DNS and wall-resolved LES data with orders of magnitude reduction in cost. Moreover, they demonstrate the implementation requirements necessary to achieve this accuracy.
Prediction of a Crack Propagation in a Steam Turbine Rotor
Authors: Chatterton Steven , Pennacchi Paolo , Vania Andrea , Dassi Ludovico 
Published: August 2024

Abstract
The early detection of shaft cracks in rotating machines is essential to avoid catastrophic damage, long outages and high maintenance costs. An increasing number of transverse and circumferential cracks caused by thermal fatigue have been detected in steam turbines, in recent years. Because of usual long-time intervals between two subsequent planned inspections of the rotors, it is very important to identify the presence of a shaft crack by the online analysis of the harmonic content of the machine vibrations measured by Condition Monitoring Systems. As the symptoms caused by shaft cracks in the system response are often masked by the effects induced by other common malfunctions, it is very useful to study the sensitivity of the dynamic behavior of turbine shafts to the propagation of transverse cracks and to predict the lowest value of the crack depth that can cause detectable symptoms in the machine vibration. This paper shows the results provided by a numerical approach, aimed at identifying the propagation of shaft cracks, which has been applied to the analysis of a real intermediate-pressure steam turbine in which a first crack initiation had been detected.
A High-Performance Code for Analyzing Loss Transport Equations in High-Fidelity Simulations
Authors: Biassoni Daniele , Russo Matteo , Viviani Paolo , Vitali Giacomo , Lengani Davide 
Published: August 2024

Abstract
The subject of the present paper is the development of a general procedure to calculate the terms of the total pressure transport equations using a High-Performance Data Analytics (HPDA), based on Proper Orthogonal Decomposition (POD) and leveraging on High Performance Computing. This method is applied to data obtained from high fidelity simulations of low pressure turbine (LPT) blades in order to separate the different loss contributions and to visualize the associated structures to the fluid dynamics phenomena that occur inside the passage. This procedure is developed in Python environment because it easily allows parallel computing.
This paper discusses the mathematical framework behind the decomposition of total pressure transport equation and its implementation in Python. The scalability tests are performed for two exemplary datasets and compared to previous implementation showing a considerable speed-up. The procedure applied to Large Eddy Simulation (LES) data shows significant improvement over traditional approaches. It provides more detailed information about the phenomena associated with the generation of losses in the turbine blades, allowing for quick identification of where these losses occur. The HPDA code can be applied to all high fidelity simulations (LES and DNS) in order to get more information from simulations that are extremely expensive, allowing the full exploitation of such large datasets. In addition, to demonstrate the ease of code’s implementation, the data obtained from the POD are compared with data obtained from Fourier decomposition to validate the procedure. The procedure is open access and available in an online repository.