bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigating Power Augmentation of 1 MW Horizontal Axis Wind Turbine Using Auxiliary Turbines
Authors: M. R. Elbaz Ahmed , Shehab Ali 
Published: August 2024

Abstract
Researchers face challenges in enhancing wind energy efficiency to utilize a large amount of green energy at the lowest cost, as the global need for climate change mitigation increases. This paper presents a numerical study to improve the capture efficiency of a 1 MW horizontal axis wind turbine installation by making the best use of available space by employing two extra 100 kW auxiliary turbines. The proposed design concept is based on installing the auxiliary turbines below the primary turbine blade zone on both sides of the tower to catch intruding aerodynamic flow. To solve the Reynolds averaged Navier-Stokes (RANS) equations, the computational fluid dynamics (CFD) ANSYS-fluent software was utilized. Initially, a simple numerical model for a 1 MW horizontal axis wind turbine was created to simulate its performance characteristics. A steady-state solution was obtained using the Moving Reference Frame (MRF) approach for both single-rotor and multi-rotor turbines. The proposed design’s aerodynamic performance was then investigated using a transient model simulation with a sliding dynamic mesh approach. The numerical results of both steady and unsteady simulations revealed that the proposed design increased system power output by 12%.
Inverse Design of Compressor/Fan Blade Profiles Based on Conditional Invertible Neural Networks
Authors: Jia Xinkai , Huang Xiuquan , Jiang Shouyong , Wang Dingxi , Firrone Christian Maria 
Published: August 2024

Abstract
Compressors/fans are crucial components of modern aircraft engines, playing a key role in providing power and thrust, and ensuring combustion efficiency. The design of compressors and fans represents a paramount field of research and engineering necessity for which blade profile design serves as the fundamental aspect. A practical blade profile design often involves multiple constraints. Traditional design methods heavily rely on the expertise of designers, and typically require many iterations to achieve desired geometries which can be a daunting task. This paper proposes a blade profile inverse design approach based on a conditional Invertible Neural Networks to mitigate the drawbacks of the traditional methods. It can enable the direct generation of blade profiles that satisfy specified requirements, including aerodynamic performance and additional relevant constraints. This method encompasses two primary steps: forward process modeling and inverse process modeling. In the forward process, a surrogate model is established to map design parameters to blade profile performance metrics. Within a specified design space, a predetermined number of designs are sampled, and a dataset is produced through performing high-fidelity Computational Fluid Dynamics (CFD) analyses to obtain aerodynamic performance and other interested metrics. Subsequently, the dataset, after data preprocessing, is employed to train a Gaussian Process Regression model to replace costly CFD analyses. In the inverse modeling step, based on the substantial data generated by the trained Gaussian Process Regression model, a conditional Invertible Neural Network is trained, mapping design parameters to a latent space under the specified target conditions. This renders the learning of the inverse process feasible. Upon the completion of model training, the design parameters and blade geometry that meet the desired target could be directly derived. The proposed method is demonstrated using a subsonic blade profile inverse design case study.
Multi-Objective Aerodynamic Optimization of Gas Turbine Exhaust Diffuser: Experimental and Numerical Validations
Authors: Dong Yuxuan , Yang Rui , Wang Xidong , Li Zhigang , Li Jun , Song Liming 
Published: August 2024

Abstract
To improve the aerodynamic performance of a typical exhaust diffuser, a multi-objective optimization system for the shell profile of the exhaust diffuser is constructed under the condition of considering the inlet swirl. Exhaust diffuser performance is evaluated using two objectives: static pressure recovery coefficient and outlet velocity uniformity coefficient. The shell profile is defined by five control points, and the aerodynamic performance of the exhaust diffuser model is calculated using the realizable-k-ε turbulence model. The multi-objective optimization is carried out using the NSGA-II algorithm combined with the Kriging agent model, and two optimal design schemes, optimal design 1 with the maximum static pressure recovery coefficient and optimal design 2 with the best outlet velocity uniformity, are obtained. Numerical calculation and experimental measurement were carried out to evaluate the aerodynamic performance of the baseline and the optimized exhaust diffuser. The results show that the separation vortices in the two optimized exhaust diffusers are significantly weakened. The reverse pressure gradient and flow loss near the strut of optimal design 1 decrease significantly and the outflow uniformity of optimal design 2 is improved significantly. The static pressure recovery coefficient and the outlet velocity uniformity coefficient of the optimal design 1 exhaust diffuser are increased by 11.5% and 3.2%, respectively, and the static pressure recovery coefficient and the outlet velocity uniformity coefficient of the optimal design 2 are increased by 5.7% and 10.9%, respectively.
Numerical Investigation (H2/CH4) of an Industrial Gas Turbines for NOx Prediction and Validation
Authors: Arun A. K. , Rajesh M. , Cerutti M. , Pampaloni D. 
Published: August 2024

Abstract
Controlling the production of NOx for industrial gas turbine while maintaining a stable combustion operating regime for a wide variety of fuels must be addressed since the development phase. Well-established numerical practices are necessary for the development of gas turbine combustors, as they allow a significant reduction of the required testing. However, the validation of such models is crucial to the quality of the development. The first part of the paper presents the dataset available for the purpose of numerical practice validation: lab-scale experiments at atmosphere conditions had been collected for prototypal burners of an industrial gas turbine. Then the experiments have been carried out at gas turbine relevant pressure and temperatures. In both test campaign, NOx emissions have been collected as a function of burner main regulating parameters, as well as of fuel composition: in particular, data are available for either pure methane or hydrogen. The paper finally focuses on modeling guidelines for NOx prediction and the assessment of pressure losses, fuel air mixing and other combustion performance parameters.
Effects of the Shape Modification of the Leading Edge Impingement Cooling for Turbine Blade
Authors: Nita Kozo , Fujimoto Shu , Suzuki Masaya , Kazawa Junichi , Okita Yoji 
Published: August 2024

Abstract
In impingement cooling, it is important to consider eliminating the influence of crossflow to improve the heat transfer coefficient. Therefore, in this work, the effects of shape modification on the leading edge impingement cooling for the turbine blade with crossflow conditions have been investigated numerically and experimentally.
The heat transfer coefficient on the cooling side of the leading edge was calculated using CFD (RANS) in a static system. The CFD model was created using a shape that resembles a partial cut of the midspan position of the turbine blade leading edge, incorporating impingement cooling and film cooling. This was based on the effective heat transfer coefficient considering the area of impingement target surface. Shapes with installed pin-fins and varied impingement pitches were expected to have high cooling performance and be less affected by crossflow. Therefore, these shapes were selected as Opt-A and Opt-B configurations for rig testing.
In the experiment, the shape of the specimen was the same as the CFD model. The mainstream temperature and pressure were adjusted to achieve a Reynolds number equivalent to the actual operating conditions. And the cooling air for impingement and crossflow can be supplied separately. The impingement Reynolds number was varied from 9.0 × 103 to 3.0 × 104. Furthermore, to investigate the effect of crossflow, the flow rate was also varied at half, double, and zero flow rates compared to the base value.
Surface temperature was measured using calibrated Infrared thermal cameras and converted into cooling effectiveness.
Assessment of Rotordynamic Characteristics for the Hole-Pattern Damper Seal in a 150MW Steam Turbine
Authors: Zhao Weijun , Huang Biao , Zheng Chunbo , Zhang Zihan , Li Zhigang 
Published: August 2024

Abstract
Damper seals and swirl brakes have been commonly used for many years as a solution for the rotor vibration instability in multiple-stage centrifugal compressor. However, there are few literatures focusing on the application assessment of damper seals and swirl brakes in high-pressure steam turbines.
This paper presents two attempt schemes (swirl brake, damper seal) to resolve the strong subsynchronous vibration instability for a 150MW 3000rpm multistage single casing steam turbine. The rotor vibration instability has been demonstrated to be caused by the steam whirl forces generated at the balance piston seal location in combination with a long flexible rotor. The original balance piston seal scheme is a staggered labyrinth seal with both teeth on stator and rotor, yielding high cross-coupling stiffness and large negative effective damping at high inlet preswirl condition. To resolve the subsynchronous vibration instability and allow full load operation of the steam turbine, the hole-pattern damper seal schemes with/without inlet swirl brake were designed as the replacement of the original staggered labyrinth seal. A comprehensive assessment and comparison were conducted on the rotordynamic characteristics for the original staggered labyrinth seal and the new hole-pattern damper seals, using a proposed transient CFD-based perturbation method based on the multiple-frequency elliptical-orbit rotor whirling model. Results show that the present hole-pattern damper seal with inlet swirl brake produces the largest effective damping and the lowest crossover frequency, is a good balance piston seal scheme for the present steam turbine to increase the rotor net damping and eliminate the subsynchronous vibration.
Thermodynamic Analysis of a Solid-Oxide Fuel Cell Gas Turbine (SOFC-GT) Hybrid System for Marine Applications
Authors: Babaji Badamasi , Turner James W. G. 
Published: August 2024

Abstract
The maritime industry serves a pivotal role in global trade and transportation, yet its contribution to environmental pollution, notably emissions, poses a critical concern. Addressing and mitigating the carbon footprint of this industry has become imperative amidst the challenges posed by climate change. This study presents a thermodynamic analysis focused on a Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) hybrid system designed for marine applications. The integration of Solid Oxide Fuel Cells (SOFCs) with gas turbines holds significant promise for augmenting the efficiency and sustainability of marine propulsion systems. A steady-state thermodynamic model for the SOFC-GT was developed using ASPEN PLUS software, integrating built-in modules and functions along with a Fortran code specifically designed for SOFC electrochemistry. To ascertain the model’s accuracy, validation was performed against NASA’s SOFC model, established using the Numerical Propulsion System Simulator (NPSS), and publicly accessible data from a Westinghouse 120kW tubular SOFC. Both datasets exhibited a matching within a 1% error margin, validating the reliability of our model. Having established confidence in the model’s accuracy, this study investigates the intricate interactions between the SOFC and gas turbine components within the hybrid system. The incorporation of the gas turbine for heat recovery in the hybrid system utilizing the Westinghouse tubular SOFC showcased a notable increase in thermal efficiency, elevating it from 50% to 62%. The proposed hybrid system is compared to an existing marine gas turbine and has demonstrated improved thermal efficiency and reduced fuel consumption but fell short in terms of energy density.
Study on Integrated Through-Flow Method for Variable Cycle Compression System
Authors: Zhang Shuying , Fei Teng , Li Jiabin , Ji Lucheng 
Published: August 2024

Abstract
Variable cycle engine (VCE) is one of the ideal power units for advanced multipurpose aircraft. The addition of bypasses and adjustable mechanisms in the compression system enables the VCE to adjust the mass flow distribution according to the flight mission and expand the flight envelope. However, it also leads to strong aerodynamic coupling and complex matching relations between components. Therefore, it is necessary to develop an integrated design method for variable cycle compression system.
Through-flow design and analysis are important steps in aerodynamic design, which determine the meridional flow path and blade section parameters for compression system. An integrated through-flow design and analysis program for double bypass variable cycle compression system called SCAD was proposed. In the program, the whole computing domain was divided into three uninterrupted flow paths according to the position of the two splitters. Pairs of split streamlines and overlapped computing stations were set up to ensure the continuity of the flow parameters and the convergence of the iteration. It can achieve integrated coupling simulation of the front fan (FF), the rear fan (RF), and the high pressure compressor (HPC), and solve the matching problem of the variable cycle compression system in the preliminary design.
The errors of total pressure ratio and isentropic efficiency of most stages simulated by SCAD are no more than 2%, and the spanwise distributions of the key aerodynamic parameters at main flow field at each stage are consistent with the 3D CFD results, as shown in verification of a double bypass variable cycle compression system. SCAD has been applied in the design system of variable cycle compression system in China now.
Finally, the influence of the outer bypass ratio on the aerodynamic performance of the front/rear fan of the double bypass variable cycle compression system was studied by using SCAD. The results shows that the bypass ratio has little effect on the front fan, whereas the total pressure ratio and isentropic efficiency of the rear fan increase with it. When the bypass ratio is small, the increase of axial and radial velocities leads to blockage in the core flow path and decrease of rotor load. The forward blade of the tandem stator works at a large-negative-incidence condition, making the performance of the rear fan deteriorate sharply. It is reasonable to choose the design bypass ratio of the front/rear fan as 0.33.
Cylindrical Composite Structural Design for Underwater Compressed Air Energy Storage
Authors: Wang Tianqi , An Chen , Mao Yixuan 
Published: August 2024

Abstract
The utilization of renewable energy sources is pivotal for future energy sustainability. However, the effective utilization of this energy in marine environments necessitates the implementation of energy storage systems to compensate for energy losses induced by intermittent power usage. Underwater compressed air energy storage (UWCAES) is a cost-effective and emission-free method for storing energy underwater. This technology has proven to be effective and viable, and it offers significant benefits in terms of energy efficiency and sustainability. In this paper, a cylindrical composite structure UWCAES tank is designed. At first, the materials and shapes of the different forms of air containers were evaluated, and the relationship between container diameter, length, and number of air containers was analyzed on the basis of the range of energy storage densities for different kinds of systems. Subsequently, the materials to be applied in the tanks were investigated and selected according to the actual working conditions of the system. Eventually, finite element models and prediction formula were developed and the influence of changes in the thicknesses of the steel reinforcement were discussed. The results demonstrated that the storage tank possesses adequate environmental resistance and load-bearing capacity, which can provide a reference for its practical engineering implementation.
Application of Internal Heat Transfer Inverse Problem Solution Method to Jet Array Impingement Cooling System
Authors: Haslam Riess , Bacci Tommaso , Picchi Alessio , Facchini Bruno 
Published: August 2024

Abstract
Detailed thermal performance estimation of real-hardware internally cooled gas-turbine components is challenging due to the lack of optical and instrumentation access to the internal surfaces. In scaled, laboratory conditions, such estimates can be obtained by solving an inverse heat conduction problem that links the desired internal heat load distribution to a set of measured external temperatures through the solution of a partial differential equation. If sufficiently reliable, the results provide cooling system designers with valuable insights into the effects of the combinations of different cooling techniques, of secondary flows, and of manufacturing methods.
Without some form of regularization, however, such inverse problems are ill-posed in that the estimates are not uniquely defined by the temperature measurements and are highly sensitive to measurement noise. In this study, an adjoint-based deterministic optimization method is used to estimate high-dimensional internal heat transfer coefficient distributions produced by a jet-array impingement system with local extraction of post-impingement flow. A method for determining the optimum amount of regularization to apply is also adopted and validated using the experimental results.
Tests were performed by applying the impingement system in steady conditions to a heated metal plate and measuring the temperature response on the opposite side with a scientific grade infra-red camera. The particular cooling system was chosen because it produces high spatial gradients of heat transfer coefficients which are difficult to reconstruct from the external temperature measurements due to the three-dimensional conduction effects through the wall of the plate. Variations of plate thickness and Reynolds number were used to test the robustness of the method, and the resulting estimates for all conditions were compared to corresponding reference results obtained in a previous, dedicated test campaign.
CO2 Transcritical Turbines Stator Optimization for Refrigeration Applications
Authors: Renaud Saugnac , Egoï Ortego Sampedro , Chakib Bouallou 
Published: August 2024

Abstract
The main objective of this work presented in the paper is to perform an optimization of the stator nozzle. This is done using a 1D two-phase metastable model which includes a transitional interface area formulation, the Aleksandrov interface heat transfer coefficient and Schiller-Naumann interface drag model. The optimization is based on the research of an optimal pressure profile defined by Bezier curves leading to an optimal cross-sectional area profile. Various types of linear constrained optimization algorithms were explored. The results show that for inlet operating conditions close to critical point of CO2, the maximum efficiency that can be attained is always higher than at lower inlet temperature conditions. The obtained optimal nozzle profiles should be tested in subsequent experimental work in order to evaluate the performance of the method.
The Role of Operating Conditions on Flutter Instability of a Low-Pressure Turbine Rotor
Authors: Pinelli Lorenzo , Poli Francesco , Arnone Andrea , D’Ettole Antonio Giuseppe , Rosso Emanuele , Sartor Gianmaria , Kharyton Vsevolod 
Published: August 2024

Abstract
Modern trends in low pressure gas turbine design lead to lighter designs with fewer stages, thinner sections and highly loaded components. Blades are thus more prone to flutter induced vibrations that can compromise their structural integrity. Accurate predictions of flutter inception and evolution remains a challenging task. Several numerical methods have been developed for a long time and dedicated experimental campaigns have been carried out to have a better insight of flutter problems. The ARIAS EU project provided the opportunity to investigate flutter occurrences of turbine and compressor rotors with unique test benches and to test state of the art numerical techniques. In this context, the paper discusses the impact of the turbine operating conditions on flutter inception of an unstable low pressure turbine rotor extensively tested during the EU ARIAS project. The operating conditions were changed by modifying the rotor rotational speed, and the first bending and torsion mode families of a cantilever configuration have been analyzed. Numerical results reveal that an increase of the rotational speed leads to more unstable configurations for the bending mode-shape, while the torsional mode-shape moves from stable to unstable condition when lowering the rotational speed. Such numerical evidence has been confirmed by the blade tip timing acquisition technique also in terms of most unstable nodal diameter. Finally the limit cycle amplitudes measured with the tip timing are compared with the results of a vibration amplitude estimation method based on a combination of acoustic measurements and computational results.
Design for Sustainability of Gas Turbines: Accuracy on Carbon Footprint at Different Design Steps
Authors: Al Freijat Mosè , Orlandi Rachele , Pucciarelli Martina , Ragni Giacomo , Serra Angela , Fantozzi Francesco 
Published: August 2024

Abstract
In current scenario, industries and Governments are fighting against Global Warming and increasing the focus on environmental impact of products. Industries are taking commitment to reduce their GHGs emissions. Sustainable Product Development (SPD) is a methodology that can be used by companies to assess and therefore reduce environmental impact of new products. Since the design of the product will determine its performances, environmental performance must be considered as well in early design phase. Industries are so far experiencing an increasing attention in eco-design, which can be considered as a system of practices for designing a better performing product in terms of environmental impacts. In the design process, which foresees three distinct phases (conceptual, preliminary, detailed), uncertainties related to undefined features and information can affect the environmental impact estimation and a Life Cycle Assessment (LCA) could not be performed. This work aims to analyze this issue by a case study in the field of turbomachinery sector: the New Product Development (NPD) of a gas turbine is used as the opportunity to quantify the accuracy of an LCA performed in the early design, through the three steps, varying the defined information about the under-development product. The use case is a set of forged wheels of an aeroderivative gas turbine, which allows to analyze several scenarios of uncertainty: material, production process, production country, geometry. Focus is on Carbon Footprint (CF) assessment.