bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluating Thin-Film Thermocouple Performance on Additively Manufactured Turbine Airfoils
Authors: Berdanier Reid A. , Nunn Margaret R. , Brumberg Justin T. , Barringer Michael D. , Fishbone Scott , Thole Karen A. 
Published: August 2024

Abstract
As gas turbine engine designs continue to target higher turbine entry temperatures for increased thermal efficiency, gas turbine manufacturers and operators require additional feedback from life-limited engine components. Moreover, additively manufactured (AM) hardware is becoming more prevalent in the engine development cycle to reduce component lead times and associated costs. Although additive manufacturing unlocks unique capabilities for sensor integration, the inherent roughness from additive surfaces poses unique challenges to the direct-write sensor installation processes. The current study addresses these realities by demonstrating sensor operation on additively manufactured vane hardware in a turbine research facility operating at scaled conditions. Thin-film thermocouples were deposited on fully-cooled AM turbine vanes and tested over a range of operating conditions in a one stage research turbine at Penn State University. The low-profile surface-mounted sensors were compared with traditional small-diameter embedded thermocouples in terms of calibration accuracy and durability. A comparison between traditional masked thermal spray and direct-write installation was also evaluated as part of the sensor integration strategy for the AM vanes. Ultimately, this study shows thin-film thermocouples on additively manufactured airfoils can operate reliably over an extended test campaign in rig-scaled conditions. Furthermore, the measurement accuracy of thin-film thermocouples demonstrated through this study is equivalent to traditional mineral-insulated thermocouple sensors showing the utility of these technologies for future turbine research and development applications.
Numerical Analysis of a Nozzle Guided Vane Filled With Lattice Structures
Authors: Senegaglia Ivan , Grossi Tommaso , Macoretta Giuseppe , Monelli Bernardo Disma , Fardelli Andrea , Tripoli Girolamo , del Turco Paolo , Colantoni Simone 
Published: August 2024

Abstract
Gas turbines play a critical role in industries such as power generation and aviation. Additive manufacturing has emerged as a game-changing technology for gas turbine components, offering superior design flexibility and performance enhancements. The present work provides an overview of a multistep approach for integrating lattice structures into a specific gas turbine component, the Nozzle Guide Vane (NGV), using additive manufacturing technology. The first step involves a comprehensive assessment of lattice structures’ influence on the mechanical and thermal properties of the exposed part of NGV. Through computational simulations and experiments, an ideal lattice geometry is determined, optimizing structural integrity and heat transfer properties while minimizing volume usage. The second step sets the baseline performances of the current NGV system components, which were investigated and selected for additive manufacturing analysis. The third step focuses on the overall effect of additive manufacturing capabilities in the NGV system. The fourth and final step optimizes the additive manufacturing process for fabricating gas turbine components with lattice structures. Laser Powder Bed Fusion (L-PBF) technology, united with advanced Topological Optimization analyses, and high-temperature alloys were selected to withstand the demanding gas turbine operating conditions. This multistep approach represents a significant step forward in gas turbine technology, capitalizing the advanced mechanical applications as lattice designs and additive manufacturing, aiming in enhanced performance, reduced weight, and improved efficiency. These developments hold the potential to achieve more sustainable and cost-effective energy generation and transportation systems.
Digital Value Tool for Gas Turbine Digitized Cross Section
Authors: Moscardini Marigrazia , Filice Valentina , Cini Gianni , Tapinassi Libero , Berti Matteo , Brogelli Riccardo , Del Turco Paolo , Ragni Giacomo 
Published: August 2024

Abstract
Digital Value Tool (DVT), an innovation tool, has been developed to digitalize the conceptual Cross Section of Gas Turbines (GTs). The tool aims at reducing the lead time of the conceptual design process, speeding up the development of the conceptual cross section, pursuing a standardized approach in order to improve quality. DVT is programmed in C++ and C#, and it is built by .dll files developed in the NXOpen environment. The digitalization of the cross section is based on: GT input data, component pre-sizing based on design rules and verification loops, dynamic environment and interface automatization obtained by a dedicated parametrization. One of the main goals is shifting from the manual generation of conceptual design of cross section to a digitalized one, which is characterized by the components and their sketches being stored inside the .prt file of the 2D model. In order to achieve this goal, virtual blocks containing geometrical and non-geometrical information are automatically generated and associated to the designed components. This guarantees the storage of the engine’s DNA inside a unique file. A dedicated feature allows exporting the information inside an .xml file, which organizes data according to a tree structure resembling the engine modules. Both the .xml and .prt file cover the whole communication protocol with external tools carrying out conceptual analysis such as: component conceptual costs, rotodynamic analysis, secondary flows and thermal evaluation, clearances assessment.
The tool is constantly updated and populated for a continuous improvement being at the cutting edge of new technologies. Moreover, DVT is implemented in most of referenced industrial GT configurations.
Adjoint-Based Optimization for the Venturi Mixer of a Burner
Authors: Xu Min , Radwan Akram , Xia Yu 
Published: August 2024

Abstract
The optimization of Venturi mixers in burners is critical for enhancing combustion efficiency and minimizing emissions. In this study, we utilize the adjoint method to analyze and refine the design of a Venturi mixer. Our numerical simulations integrate the species transport equation with the Eddy Dissipation Model (EDM) for reacting flow and the generalized k-ω (GEKO) model to simulate turbulence. By solving adjoint equations, we effectively compute the shape sensitivity for various observables, including pressure drop, outlet fuel variance/uniformity deviation index, air and fuel mass flow rates, and outlet CO mass fraction. The shape sensitivity analysis uncovers the interplay between the observables and the appropriate weights for multiple objective optimizations. Subsequently, we perform gradient-based optimizations to enhance the mixer’s performance, employing both shape sensitivity and mesh morphing techniques. We conduct a series of case studies focusing on both cold and reacting flows. The optimization of cold flow provides an in-depth exploration of various optimization strategies, encompassing single-objective and multi-objective optimization with diverse weight combinations. Following this, the optimization under reacting flow conditions improves the fuel/air mixing, leading to the increase of combustion efficiency and hence the reduction of CO emissions. Our findings showcase the potential of an adjoint-based optimization framework in designing Venturi mixers that are efficient and emit lower levels of pollutants.
Aerodynamic Performance Improvement and Noise Control for the Multi-Blade Centrifugal Fan in Air Conditioner by Using Concave Volute Tongue
Authors: Lei Jian , Qin Guoliang , Cui Qin 
Published: August 2024

Abstract
The structural formation of the multi-blade centrifugal fan’s volute tongue results in a complex flow pattern. This study focuses on the design of a concave volute tongue structure to address the issues of volute tongue backflow and blade path backflow. A Bezier curve with five control points was utilized to accurately shape the profile of the concave volute tongue. Five different solutions for the concave volute tongue were developed. Comparative analysis results show that the depth of the volute tongue depression has minimal impact on the fan’s efficiency performance. However, the amplitude of noise reduction initially increases and then decreases as the depth of the volute tongue depression increases. Experimental tests and numerical simulations indicate that the implementation of the concave volute tongue structure effectively suppresses volute tongue backflow and blade channel backflow at the impeller outlet, resulting in a maximum reduction in aerodynamic noise of 0.8 dB. The sound pressure level of the multi-blade centrifugal fan with the concave volute tongue structure is lower in most frequency band under low static pressure conditions compared to its original design. The V3 multi-blade centrifugal fan demonstrates better static pressure performance across all working conditions, particularly at high flow rates. The V3 multi-blade centrifugal fan exhibits a 10.1 Pa increase in the maximum static pressure level compared to its original design. These improvements in static pressure and flow capacity of the multi-blade centrifugal fan contribute to energy savings and a reduction in pollutant emissions.
Film Cooling Performance Comparison of Blade Tips With a Trailing Edge, Pressure Side Cutback or a Suction Side Squealer in a Transonic Linear Cascade
Authors: Yeh Ming-Feng , Burdett Timothy A. , Wright Lesley M. , Han Je-Chin 
Published: August 2024

Abstract
Film cooling effectiveness and leakage flow play crucial roles in turbine blade heat transfer. In contrast to the conventional trailing edge cutback squealer blade tip (CB-tip), this study aims to compare the film cooling effectiveness of a suction side squealer tip (SS-tip) under different blowing ratios (M = 1.0, 1.5, 2.0) and density ratios (DR = 1.0, 1.5, 2.0).
This experiment is conducted in a 3-blade cascade wind tunnel under transonic conditions, with inlet and outlet Mach numbers equal to 0.29 and 0.75, respectively. While applying the Pressure Sensitive Paint (PSP) technique for film cooling effectiveness measurements, both top-view and side-view perspectives were employed to illustrate the distribution of local cooling effectiveness across various regions of the blade. Furthermore, two coolant injection scenarios were investigated: (i) combined tip and pressure side cooling and (ii) pressure side-only cooling. In addition to measuring the surface effectiveness, PSP can also be used to estimate the leakage flow across the blade tip by analyzing the local static pressure distribution.
For the CB-tip, the film cooling effectiveness within the cavity increases as both the blowing ratio and density ratio increase. The PSP technique clearly captures the accumulation of coolant within the cavity and the coolant discharge near the trailing edge in the vicinity of the squealer cutback. When the blade tip is outfitted with only a suction side squealer, the film cooling effectiveness on the blade tip is comparable to that of the full squealer with the trailing edge cutback. This similarity is achieved as the CB-tip design requires 14–20% more coolant to achieve the same blowing ratios as the SS-tip. The advantage of the suction side squealer is further demonstrated as leakage flow across the tip is reduced compared to the conventional, full squealer with a trailing edge cutback.
Design of Broadband Liner Based on Cremer Concept
Authors: Zhang Ji , Qiu Xianghai , Du Lin , Sun Xiaofeng 
Published: August 2024

Abstract
In recent years, various novel acoustic liners have been proposed to meet the broadband noise reduction requirements of turbomachinery, such as multi-degree-of-freedom liners. However, the increasing number of adjustable geometric parameters brings about the complexity of liner design. The Cremer concept has commonly been employed to the rapid preliminary design of acoustic impedance. This paper presents a broadband liner design method, which achieves rapid design of liner geometric parameters by incorporating the impedance prediction model into the Cremer concept. Moreover, this method maximizes the match between the optimal impedance spectrum and the liner impedance spectrum, thereby achieving the desired objective of broadband sound absorption for the liner. Taking the uniform single- and double-degree-of-freedom liner as examples, three optimization strategies are evaluated in this paper: 1) the least squares method; 2) minimization of cavity depth; 3) multi-frequency optimization. Extensive optimization results show that the noise reduction bandwidth of a single-degree-of-freedom liner is related to the cavity depth, and the widest bandwidth liner can be designed by targeting two specific Helmholtz numbers. Similarly, the noise reduction bandwidth of a double-degree-of-freedom liner is related to the cavity depth near the fluid, and the widest bandwidth liner can be designed by targeting four specific Helmholtz numbers. For more complex liners, as long as an appropriate impedance model is available, this method is expected to expedite the design process and alleviate design complexity.
Unsteady Flow, Turbulence and Acoustic Measurements on the Counter-Rotating DLR Turbo Fan Stage CRISPmulti, With and Without Inlet Distortions
Authors: Meyer Robert , Tapken Ulf , Klähn Lukas , Behn Maximilian , Lengyel-Kampmann Timea 
Published: August 2024

Abstract
Extensive aerodynamic and acoustic measurements were carried out on a counter-rotating turbofan (CRISP) stage under the influence of inlet distortions that are representative of the boundary layer ingestion of an engine embedded in the aircraft fuselage. The unsteady flow field was measured and analyzed using hot-wire anemometry upstream, between and downstream of the rotors, both with and without inlet distortions. Acoustic measurements were carried out using extensive microphone arrays on the intake and exhaust sides of the fan. This article presents exemplary measurement results, which show the significant effect of inlet distortions on turbulence and fan sound excitation.
Experimentally Verified Optimization of a Two-Stage Real Gas Centrifugal Compressor Using an Industrial-Ready Adjoint Method
Authors: Hanimann Lucian , Fleischli Benno , Mangani Luca , Casartelli Ernesto , Weickgenannt Ansgar , Lehr Andreas 
Published: August 2024

Abstract
Ozone depletion and global warming are major drivers for the development of cooling systems. Accordingly, new governmental regulations for the equipment are continuously introduced. The redesign of corresponding centrifugal compressors for new refrigerants is therefore necessary and remains a very challenging task. The vicinity to the two-phase region requires accurate real gas models and the complexity of the flow patterns a robust numerical integration of the underlying governing equations. This is particularly true for the considered low flow coefficient two stage centrifugal compressor. Classical design and optimization methods are limited in their flexibility because of the geometry parametrization, thus affecting the development of the next generation of turbo compressors.
This article describes the development and application of a fully-coupled, pressure based CFD framework, incorporating a highly flexible discrete adjoint method used for redesign and optimization purposes. The maturity of the underlying CFD and of the optimization algorithm makes it possible to account for real gas and turbulence effects, as well as multiple mixing-plane stage interfaces. Accordingly, it is possible to fully exploit the major advantage of this gradient based optimization strategy, the independency between computational effort and the number of degrees of freedom in the geometrical description.
Using a two-stage centrifugal compressor, the return channel is optimized to achieve an overall reduction in entropy generation. Although being a single point optimization, the resulting performance characteristic shows a consistent improvement over the whole operating range with maximum values of up to two percent. The resulting geometry is manufactured and experimentally tested on the test rig. The computationally obtained efficiency increase can be confirmed by the experimental data.
Effects of the Geometric Uncertainties of Bladed Disks Through the Analytical Derivatives of the Finite Element Matrices
Authors: Bouras Abdelhakim , Carassale Luigi 
Published: August 2024

Abstract
Manufacturing processes and wear are known to create imperfections in mechanical components that may result in a significant deviation of the modal properties from their predicted values. This is especially true for symmetric structures such as bladed disks, where even small variations in the blade geometry can cause mistuning. The effect of parameter variations on the model is commonly assessed through sensitivity analysis within the framework of uncertainty propagation or structural optimization. Different formulations are available when dealing with the variation of a single scalar parameter. The problem becomes more complicated when the source of the variation is the whole component geometry. To deal with this case, it is necessary to define a representation able to describe the shift from the nominal geometry through a finite set of parameters and compute the derivatives of the system matrices with respect to those parameters. This paper proposes to compute analytically the derivatives of the system matrices with respect to the geometric variations. The derivatives are calculated at the finite element (FE) level, and then are assembled into global derivative matrices. Using directional derivatives, the sensitivities of the system matrices are computed with standard FE numerical schemes based on the nominal geometry.
Performance Simulation and Off-Design Performance Control of Reheat Gas Turbine Engines
Authors: Li Yi-Guang , Liu Yang 
Published: August 2024

Abstract
A reheat gas turbine engine with a sequential combustion system has the potential to offer high cycle efficiency at moderate turbine entry temperatures. Consequently, it has one more degree of power setting control, which offers more flexible but also more complex control of engine off-design operations. An example of such a design with reheat is GT24/GT26 industrial gas turbine engines. In this paper, a novel simulation method for off-design thermodynamic performance of reheat gas turbines has been introduced and a novel performance control schedule for part-load operations at various ambient conditions have been proposed aiming to keep the relative workloads between the two turbine sections constant. The proposed control schedule is simple and can be adapted easily. By applying the off-design performance control schedule to a model reheat industrial gas turbine engine similar to GT24/GT26 gas turbine engines, the performance of the model engine is simulated at different part-load and at different ambient pressures and temperatures. The results show that by applying the proposed off-design performance control schedule, the model reheat gas turbine engine could operate effectively at different part-load operating conditions and at different ambient conditions with both turbine sections keeping nearly constant workload distributions.
Smart Industrial Gas Turbine Low-Cost IoT Architecture
Authors: Panov Vili , Cruz-Manzo Samuel , Goloshchapov Egor 
Published: August 2024

Abstract
The smart energy systems, based on the numerous digital technologies, became an integral part of the current efforts to revolutionize energy production. One of the main cornerstones of smart energy concept is connectivity, which is typically enabled through Industrial Internet-of-Things (IIoT) technology.
In this contribution we present a development of Low-Cost Internet-of-Thing (IoT) architecture with the intention to provide a secure and reliable connection of Industrial Gas Turbine (IGT) systems with Cloud environment. We utilized simulation environment, to explore integration of the Executable Digital Twin with IoT Gateway, with subsequent deployment onto dedicated Low-Cost Edge platform.
The developed IoT gateway architecture encompasses key features related to connectivity, computing power, and communication capability. The proposed Low-Cost IoT architecture supports Live Data Streaming (LDS) which allows remote monitoring and Real-Time (RT) analytics of IGT system. The IoT gateway platform satisfies the requirements attributed to secure and fast onboarding process, and moreover cost efficiency and scalability.
The devised Edge system, via reliable connection to the IGT control system, is able to collect, enrich and transfer data, for the purpose of the local and remote analytics and visualization. The Gas Turbine (GT) trackable data (sensor measurements and control signals) are enriched with the virtual engine data (soft sensors and internal health parameters) generated by the Executable Digital Twin (xDT) and streamed to the Cloud platform, where the Real-Time analytics and optimization of assets are carried out.
Feasibility and viability of proposed design are disused in this study, and we present Live Data Streaming into Amazon Web Services (AWS) Cloud environment, configured for the Real-Time monitoring of the Industrial Gas Turbine engine.
A Comprehensive Thermodynamic Analysis of Gas Turbine Combined Cycles With Pressure Gain Combustion Based on Humphrey Cycle
Authors: Dubey Abhishek , Sorce Alessandro , Stathopoulos Panagiotis 
Published: August 2024

Abstract
The paper describes a comprehensive thermodynamic analysis of the gas turbine combined cycle (CC) equipped with pressure gain combustion (PGC) based on the Humphrey cycle. PGC is represented by a steady-state zero-dimensional constant volume combustion (CVC) model with practical loss models for a realistic interpretation. Simulations were performed in WTEMP (Web-based Thermo-Economic Modular Program) software, a modular cycle analysis tool developed at the University of Genova. PGC gas turbine combined cycle is studied using methane as fuel with three different configurations of heat recovery steam generator, namely, one pressure-level without reheat, two pressure-level with reheat and three pressure-level with reheat, in order to study a wide range of CC application. An on-design performance map of the PGC gas turbine is presented and a sensitivity analysis is performed to understand the impact of cycle loss parameters and turbine cooling technology. Results were analyzed at the optimistic and realistic PGC loss scenarios. For the PGC open cycle, with optimistic combustor losses, efficiency was higher than Joule at all operating conditions. However, with realistic combustor losses, a higher TIT was found to alleviate some of the losses in the combustor and at a pressure ratio of 25, a 1700°C TIT cycle showed a benefit of 1.7 p.p., while 1300°C TIT showed no advantage. Moreover, with the reduction in first turbine stage efficiency from pulsating outflow, only the high TIT cycle showed benefit at pressure ratios less than 15. Looking into combined cycles with realistic combustor losses, PGC was found to be advantageous in terms of specific work but not efficiency at actual operating conditions. However, with a further reduction of combustor-related losses, the PGC CC could outperform the Joule equivalent in terms of efficiency. The sensitivity analysis with losses showed that the mitigation of constant pressure combustion loss is more important than the inlet pressure loss for PGC in CC application. Finally, it was shown that the improvements in turbine cooling technology could increase the efficiency of a high TIT PGC combined cycle by 0.25 p.p. and specific work output by 4.1 p.p.