bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimized J Evaluation Scheme for the Fracture Mechanics Assessment of Complex Piping Systems Subjected to Various Loading Sets
Authors: Chapuliot Stephane , Marie Stephane 
Published: September 2022

Abstract
This paper describes an optimization scheme for the J parameter calculation of cracks postulated in complex geometrical configurations such as elbow entries/exits and/or thickness transitions. The principle of this scheme comes from the RSE-M/5.4 Appendix allowing the definition of a specific compendium for given configurations. After a detailed presentation of the numerical protocol, an illustration of the required effort and the potential benefits is proposed for an elbow configuration. It is then shown that: The effort is significant but can be anticipated and automated and The potential benefit in terms of applied J is significant (a ratio of three in the proposed application).
Study on Effects of Spanwise-Expansion Parameters on Film Cooling Effectiveness of Diffusion Shaped Hole Configurations
Authors: Liu Cun-Liang , Li Bing-Ran , Song Hui , Chen Lei , Wang Rui , Wang Yong-Ming , Liang Da-Peng 
Published: September 2022

Abstract
Diffusion shaped holes are widely used on aero-engine turbine blades for film cooling. The effect of the spanwise-expansion angle and spanwise width of the hole exit on the film cooling effectiveness of diffusion shaped holes was investigated in this study. The film cooling effectiveness was obtained through the pressure-sensitive paint (PSP) technique on a plate model at five momentum ratios (0.11, 0.43, 0.97, 1.73, and 2.71). A numerical simulation was performed to analyze the flow mechanism. The laid-back fan-shaped (LBFS) holes and the fan-shaped holes with three spanwise-expansion angles (FS-A: 7 deg, 11 deg, and 15 deg) and with three spanwise widths of the hole exits (FS-B: 1.7d, 2.3d, and 3.4d) were used for the study. The results revealed that the film cooling effectiveness of fan-shaped holes (FS-A) increases monotonically as the spanwise-expansion angle increases, while the film cooling effectiveness of the LBFS holes increases first and then decreases as the spanwise-expansion angle increases. However, the film cooling effectiveness of the two kinds of holes (LBFS and FS-B) both increase first and then decrease with the increase of the spanwise width of hole exit. The mainstream intrusion occurred at the same spanwise width of the hole exit of 3.4d for both kinds of holes. The laid-back fan-shaped hole possessed high resistance to cooling performance decline. The importance of the spanwise width of the hole exit as a key parameter was emphasized in this study.
Magnetic Resonance Velocimetry of a Turbine Blade With Engine-Representative Internal and Film Cooling Structures
Authors: Ma Haiteng , Liu Yisu , Lai Youkui , Ouyang Hua , Ning Jia , Jiang Xianwang , Xu Qin 
Published: September 2022

Abstract
As a key technology to ensure turbine survival, blade cooling encompasses a whole range of strategies with ever-increasing geometric complexities. Flow measurement for turbine blades with such intricate internal and external cooling structures is very challenging and calls for non-intrusive, three-dimensional measuring techniques. As a response, this work utilizes magnetic resonance velocimetry (MRV) to measure the velocity field in a scaled turbine blade with engine-representative internal and film cooling structures. Internal cooling structures include leading edge impingement cooling, U-shaped serpentine passage with/without turbulence ribs at blade mid-chord, and trailing edge pin fins. External cooling structures include film holes near the leading edge stagnation point, at the blade tip, and on the trailing edge. Experiments were performed in water and the Reynolds number local to the leading edge, mid-chord, and trailing edge cooling channels falls within the range typically reported in the literature. This is the first time that MRV is used to measure the flow field of a turbine blade with all the typical internal and external cooling geometries combined. The results show that MRV has great capacity in measuring the complex fluid flow associated with blade cooling designs. Vortical flow features in leading edge impingement cooling, and at the U-bends of mid-chord serpentine channel are captured. Interestingly, internal flow around pin fins redistributes the velocity of external flow ejected from trailing edge slots and film holes, indicating strong coupling between the internal and film cooling flow of the turbine blade.
A Fluid–Structure Interaction Tool Using a Van der Pol-Based Reduced-Order Model for Buffet and Nonsynchronous Vibrations
Authors: Hollenbach Richard , Kielb Robert , Hall Kenneth 
Published: September 2022

Abstract
This paper builds upon a two-degree-of-freedom Van der Pol oscillator-based reduced-order model for studying the mechanisms around nonsynchronous vibrations (NSV) in turbomachinery. One degree tracks the fluid motion utilizing a combination of a traditional Van der Pol oscillator and a Duffing oscillator; the other degree of freedom is a mass on a spring and a damper, in this case, a cylinder. Thus, this model can be considered one of fluid–structure interaction. The cubic stiffening from the Duffing oscillator proved to improve the match to experimental data. Using this model to study the time history of the fluid and the structure oscillation, additional parameters are extracted to understand the underlying mechanisms of frequency lock-in and limit cycle oscillation. First, the phase shift between the vortex shedding and the structural motion is calculated when it locks-in and then unlocks. Second, the work done per cycle is analyzed from the contributions of the mass, spring, and damping forces to determine the dominant contributor when locking-in versus unlocking. Third, the phase portrait is plotted on a Poincaré map to further study the locked-in versus unlocked responses. This model is then validated against not only experimental data but also computational simulation results and previous reduced-order models. The finalized model can now serve as a preliminary design tool for turbomachinery applications. For more realistic and accurate modeling, the third degree of freedom in the form of an airfoil pitching motion will be added in a separate paper as well.
Azimuthal Instabilities of an Annular Combustor With Different Swirling Injectors
Authors: Rajendram Soundararajan Preethi , Durox Daniel , Renaud Antoine , Candel Sébastien 
Published: September 2022

Abstract
Experiments are carried out on the laboratory-scale MICCA-Spray annular combustor to examine the effects of swirlers on combustion instabilities. This system comprises 16 spray-swirl injectors and gives rise to instabilities coupled by azimuthal modes. Five types of swirlers producing clockwise rotation and varying in swirl numbers and pressure drops are considered. These swirlers can be broadly categorized into two groups: lower-swirl and higher-swirl groups, based on their swirl numbers. An arrangement where clockwise and counterclockwise swirlers alternate is also studied. Experiments are performed systematically with liquid heptane at five levels of thermal power and six equivalence ratios. Results reveal that none of the swirlers in the lower-swirl category exhibit instability in the operating region considered, whereas the higher-swirl units feature strong azimuthal instabilities that trace an overall limit cycle envelope with a few short and random bursts. Among the higher-swirl group, a higher pressure drop swirler is associated with a broader instability map. This shows that the transition to instability mainly depends on the swirl number through its effect on the flame structure and that the pressure drop adds to further variations in amplitude and frequency of oscillation. The spin ratio time series indicate that the modes are of mixed type and that their distribution depends on the operating condition. On specifically comparing the spin ratio distribution between a full set of clockwise rotating (CR) swirlers and a configuration where clockwise and counterclockwise rotating swirlers (CCR) are alternatively placed, it is found that there is no definite statistical preference for spin ratio linked to the effect of bulk swirl. In some cases, however, the CCR configuration promotes a broader distribution of spin ratios centered around the standing mode (sr = 0) while the CR setup favors azimuthal modes spinning in the counterclockwise direction. An attempt is made to interpret the occurrence of instabilities by making use of flame describing functions (FDFs) measured in a single-injector combustor. It is found that the FDFs corresponding to the two swirler categories (lower-swirl and higher-swirl) are relatively distinct. The observed behavior is tentatively interpreted using an instability analysis in which the injector and upstream plenum are represented by an impedance that shifts the band of instability. The unstable behavior is then linked to the relative position of the FDF phase with respect to the instability band in the frequency range corresponding to the expected azimuthal mode frequency. The phase and gain of the FDF notably depend on the swirl number, and it is possible to distinguish, for the present configuration, a category of low swirl number injectors inducing stable operation and another category of high swirl number units leading to oscillations.
Analysis of a Multi-Generation Renewable Energy System With Hydrogen-Fueled Gas Turbine
Authors: Bahlawan Hilal , Losi Enzo , Manservigi Lucrezia , Morini Mirko , Spina Pier Ruggero , Venturini Mauro 
Published: September 2022

Abstract
Solar energy is considered one of the most affordable renewable resources for meeting current energy demands and mitigating environmental problems. However, the exploitation of solar energy is challenging because of both diurnal and seasonal variations. Power-to-hydrogen technologies can play a key role to counterbalance the variation of solar irradiance. Moreover, hydrogen-fueled gas turbines are considered promising technologies to decarbonize the electricity sector. To tackle these concerns, this paper presents a multigeneration energy system operated in island mode in which a hydrogen-fueled gas turbine is coupled with a solar photovoltaic plant, an electrolyzer, an absorption chiller, electric and thermal energy storage, as well as a hydrogen storage. Therefore, the energy system is 100% based on renewable energy. The sizes of the components are optimized by maximizing the exploitation of renewable energy sources, while the supply of electricity from the national grid must be null. Moreover, the effect of ambient conditions on the optimal sizing is also investigated by considering the thermal, cooling, and electrical energy demands of two case studies located in two different climatic zones. The paper demonstrates that the adoption of hydrogen-fueled gas turbines coupled with power-to-hydrogen technologies can effectively support the transition toward a clean energy supply. Moreover, this study provides a procedure for the optimal sizing of a multigeneration energy system fully based on solar energy, by also demonstrating that both photovoltaic (PV) panel area and hydrogen storage volume are feasible, if compared to the considered district layout.
A New Interpretation of Hot Gas Ingress Through Turbine Rim Seals Influenced by Mainstream Annulus Swirl
Authors: Graikos Dimitrios , Tang Hui , Sangan Carl M. , Lock Gary D. , Scobie James A. 
Published: September 2022

Abstract
Rim seals are fitted at the periphery of the stator and rotor disks to reduce the adverse effects of hot gas ingress on highly stressed turbine components limited by temperature. Ingress is induced by rotational effects such as disk pumping, as well as by asymmetric pressure-driven unsteady phenomena. These influences superpose to form a complex flow-physics problem that is a challenge for computational fluid dynamics. Engine designers typically use practical low-order models that require empirical validation and correlating parameters. This paper identifies the swirl ratio in the mainstream annulus as a dominant characterizing parameter to predict ingress. This is a new interpretation that is supported by extending a low-order model based on turbulent transport using an effective eddy mixing length based on the difference in swirl between the annulus and seal clearance. Experimental measurements were made using a 1.5-stage turbine rig at low Reynolds number. The influence of annulus swirl ratio was investigated over a range of flow conditions and two rim-seal geometries, with the ingress quantified using CO2 tracer concentration in the sealing flow. The concentration data were complemented by measurements in the annulus using a five-hole aerodynamic probe.
Aging Effect–Aware Finite Element Model and Parameter Identification Method of Lithium-Ion Battery
Authors: Tian Aina , Yang Chen , Gao Yang , Jiang Yan , Chang Chun , Wang Lujun , Jiang Jiuchun 
Published: September 2022

Abstract
Battery aging is an inevitable macroscopic phenomenon in the use of the battery, which is characterized by capacity decline and power reduction. If the charging and discharging strategy does not adjust with the aging state, it is easy to cause battery abuse and accelerate the decline. To avoid this situation, the aging model with consideration of the battery degradation is coupled into the pseudo-two-dimensional (P2D) model. An aging effect-aware finite element model that can describe battery physical information accurately is presented in this article. The model parameters are divided into four parts: structure parameters, thermodynamic parameters, kinetic parameters, and aging parameters. The identification experiments are designed based on the characteristics of these types of parameters. The decoupling and parameter identification methods of kinetic parameters according to the response characteristics of each parameter under specific excitation, and state-of-charge (SOC) partitioned range identification technology of aging parameters is proposed and verified. Finally, the aging effect-aware model and the identification parameters are verified under constant current (CC) and different dynamic conditions with different charge rate (C-rate). The ability of the proposed model to track the aging trajectory in the whole life cycle is verified under various cycle conditions. The proposed model can be applied to aging mechanism analysis and health management from point of inner properties of the batteries.
Numerical Study of Large Footprint (24 × 24 mm2) Silicon-Based Embedded Microchannel Three-Dimensional Manifold Coolers
Authors: Wei Tiwei , Hazra Sougata , Lin Yujui , Gupta Man Prakash , Degner Michael , Asheghi Mehdi , Goodson Kenneth E. 
Published: September 2022

Abstract
Silicon-based embedded microchannel with three-dimensional (3D) manifold (MF) μ-cooler offers lower pressure drop and increased heat removal capability (&gt;1 kW/cm2) for microprocessors and power electronics cooling using single-phase water. In this paper, we present a thermal–fluidic numerical analysis of silicon-embedded microchannel cooling. We develop a full-scale computational fluid dynamics (CFD) model of a large footprint (24 × 24 mm2) device having embedded microchannels and a 3D manifold. It is found that the pressure/velocity distributions at three different critical regions inside the inlet manifold have a significant impact on the temperature distribution. A previous study reported a shift of the chip temperature hot-spot at high flow rates; this study delves deep into the flow and pressure variations within the MF and cold plate (CP) that leads to this shift. This study also investigates the degree of flow maldistribution, first between the manifold channels caused by the plenum and then between the cold plate channels caused by individual MF channels. Finally, this study concludes with a comparison between two different 3D manifold inlet channel heights. The comparison reveals that the manifold with 1.5 mm thickness can reduce the pressure drop by a factor of 4 while maintaining the same thermal resistance of 0.04 K cm2/W, thus indicating an increase in the coefficient of performance (COP) by a factor of 4, compared with a manifold thickness of 0.7 mm.
Predictions of the Elastic–Plastic Compressive Response of Functionally Graded Polymeric Composite Lattices Manufactured by Three-Dimensional Printing
Authors: Plocher János , Tagarielli Vito L. , Panesar Ajit 
Published: September 2022

Abstract
We use three-dimensional printing to manufacture lattices with uniform and graded relative density, made from a composite parent material comprising a nylon matrix reinforced by short carbon fibers. The elastic–plastic compressive response of these solids is measured up to their densification regime. Data from experiments on the lattices with uniform relative density are used to deduce the dependence of their elastic–plastic homogenized constitutive response on their relative density, in the range 0.2–0.8. These data are used to calibrate finite element (FE) simulations of the compressive response of functionally graded lattices (FGLs), which are found in good agreement with the corresponding measurements, capturing the salient features of the measured stress versus strain responses. This exercise is repeated for two lattice topologies (body-centered cubic and Schwarz-P). The phenomenological constitutive models produced in this study can be used in topology optimization to maximize the performance of 3D-printed FGLs components in terms of stiffness, strength, or energy absorption.
Diffraction and Refraction of Nonlinear Waves by the Green–Naghdi Equations
Authors: Hayatdavoodi Masoud , Cengiz Ertekin R. 
Published: September 2022

Abstract
Diffraction and refraction of nonlinear shallow water waves due to uneven bathymetry are studied by use of the Green–Naghdi (GN) equations in three dimensions. A numerical wave tank consisting of deep, transitional, and shallow regions is created. Various forms of three-dimensional bathymetry, consisting of ramps with nonuniform profiles and large slopes, are used to connect the deep-water side of the tank to the shallow water shelf. A wavemaker is placed at the upwave side of the domain, capable of generating solitary and cnoidal waves of the GN equations. A numerical wave absorber is located downwave of the domain to minimize the wave reflection back into the domain. The system of equations is solved numerically in time domain by use of a second-order finite-difference approach for spatial discretization, and in a boundary-fitted coordinate system, and by use of the modified Euler method for time marching. Results include solitary and cnoidal wave surface elevation and particle velocities and are compared with the existing solutions where possible. Overall, very good agreement is observed. Discussion is provided on the nonlinearity and dispersion effects on the wave diffraction and refraction by the various forms of the ramps, as well as on the performance of the GN equations in solving these problems.
A Simplified Method to Analyze Dynamic Response of VLFS Based on the Kane Method
Authors: Liu Junyi , Chen Xujun , Huang Heng , Ji Song , Tu Qunzhang 
Published: September 2022

Abstract
A two-dimensional (2D) simplified model of the very large floating structure (VLFS) is formulated based on Huston's interpretation of the Kane methodology. In this proposed model, the VLFS is considered as a series of discrete floating bodies connected by elastic hinges. The rotation stiffness of elastic hinges has a great influence on the dynamic responses of VLFS and its value is determined based on the vertical displacements equivalent between the simply supported beam model and the elastically hinged multiple bodies model with the same boundary conditions on a concentrated load. Reduced Kane equations are used in the actual dynamic analysis, once initial conditions and mechanical analysis of the system have been formulated. Validation of the Kane-based method and the reliability of the corresponding program developed are established by several comparative studies on a continuous structure and a hinged structure with three parts. The predictions based on the proposed method are essentially identical to the model test data and calculation results provided by related literature.
The Microstructural Properties and Tribological Performance of Al2O3 and TiN Nanoparticles Reinforced Ti–6Al–4V Composite Coating Deposited on AISI304 Steel by TIG Cladding
Authors: Kumar Joijode Kiran , Rao Thella Babu , Krishna Konjeti Rama 
Published: September 2022

Abstract
This investigation presents the tribological performance of (Al2O3 + TiN)/Ti6Al4V cladding deposited on AISI304 steel substrate by the tungsten inert gas (TIG) cladding approach. The microstructural characterization by SEM confirmed claddings with visually crack-free and sound metallurgical bonding at the clad layer—substrate interface. The energy dispersive spectroscopy (EDS) analysis revealed the presence of matrix and reinforcement phases as major elements with the clad layer and with considerably no oxidation during their deposition. The XRD spectra revealed that matrix and reinforcements are dominant phases in the clad layer. The formation of compounds reflected considerably a lower dilution of reinforcement phase with Ti6Al4V matrix during melting and deposition. Higher the microhardness of the (Al2O3 + TiN)/Ti6Al4V clad layer in the cladding zone compared with other clad layer compositions such as Ti6Al4V, Al2O3/Ti6Al4V, and TiN/Ti6Al4V, it is varied from 1130HV0.2 to 1222HV0.2, and the average microhardness is about 990.57HV0.2 which is 175% improvement compared with the substrate. The cladding with dual reinforcement composition has shown a superior wear resistance compared with all other clad layer composite compositions. The improvement in the wear resistance achieved with (Al2O3 + TiN)/Ti6Al4V composite clad layer deposition at 2.5 m/s, 3.5 m/s, and 4.5 m/s sliding velocities is 56.60%, 63.26%, and 68.53%, respectively, compared with the substrate. The wear morphology of the composite claddings is relatively smoother and the wear furrows are shallower compared with the substrate, especially for the composite clad layer with (Al2O3 + TiN) reinforcement phase.