bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonsymbiotic legumes are more invasive, but only if polyploid
Authors: Parshuram Zoe A. , Harrison Tia L. , Simonsen Anna K. , Stinchcombe John R. , Frederickson Megan E.
Published: October 2022

Both mutualism and polyploidy are thought to influence invasion success in plants, but few studies have tested their joint effects. Mutualism can limit range expansion when plants cannot find a compatible partner in a novel habitat, or facilitate range expansion when mutualism increases a plant's niche breadth. Polyploids are also expected to have greater niche breadth because of greater self‐compatibility and phenotypic plasticity, increasing invasion success.

For 847 legume species, we compiled data from published sources to estimate ploidy, symbiotic status with rhizobia, specificity on rhizobia, and the number of introduced ranges.

We found that diploid species have had limited spread around the globe regardless of whether they are symbiotic or how many rhizobia partners they can host. Polyploids, by contrast, have been successfully introduced to many new ranges, but interactions with rhizobia constrain their range expansion. In a hidden state model of trait evolution, we also found evidence of a high rate of re‐diploidization in symbiotic legume lineages, suggesting that symbiosis and ploidy may interact at macroevolutionary scales.

Overall, our results suggest that symbiosis with rhizobia limits range expansion when legumes are polyploid but not diploid.
The Standing and Sitting Spino‐Pelvic Sagittal Alignment in Patients with Instrumented Lumbar Fusion Might Correlate with Adjacent Segment Degeneration
Authors: Zhou Siyu , Zhong Woquan , Sun Zhuoran , Guo Yang , Zhao Yi , Li Wei , Li Weishi
Published: October 2022

Objectives

Sitting is a common weight‐bearing posture, like standing, but there still lacks enough understanding of sagittal alignment in sitting position for patients after lumbar fusion. This study aimed to investigate the accommodation of fixed spine from standing to sitting position and its influence on unfused segments.

Methods

Sixty‐two patients after lumbar fusion (test group) and 40 healthy volunteers (control group) were recruited in this research. All subjects underwent lateral radiographs of entire spine in the standing and sitting positions. The spinopelvic parameters including sagittal vertical axis (SVA), T1 pelvic angle (TPA), lumbar lordosis (LL), thoracic kyphosis (TK), and pelvic tilt (PT) were measured. The changes in parameters of patients between two positions were compared with control group, and patients were divided in different groups based on fusion level and their parameters were compared.

Results

When changing from standing to sitting positions, a forward‐moving SVA and TPA were observed in both patients and control groups, accompanied by the decrease in LL, TK and increase in PT, but the changes of patients were smaller in TPA, LL, and TK (6.5° ± 7.2° vs 9.7° ± 6.0°, 7.7° ± 8.3° vs 13.6° ± 8.5°, 2.2° ± 6.5° vs 5.4° ± 5.1°, respectively, p < 0.05). Increase of PT in the lumbosacral fixation group was lower than that in the control group (4.4° ± 9.1° vs 8.3° ± 7.1°, p < 0.05). Patients who had adjacent segments degeneration (ASD) showed more kyphosis in unfused lumbar segments than the other patients (16.4° ± 10.7° vs −1.0° ± 4.8°, p < 0.05) from standing to sitting.

Conclusions

The spine straightens in lumbar and thoracic curve, combined with forward‐moving axis and pelvic retroversion when changing to the sitting position. However, these changes are relatively limited in patients after lumbar fusion, so the adjacent unfused lumbar segments compensate to stress during sitting and this may be related to ASD.
Sirtuin 7 is essential for the survival and synthesis of oestrogen in yak (Bos grunniens) cumulus granulosa cells
Authors: Gao Shaoshuai , Yang Liuqing , Yang Xue , Xiong Yan , Fu Wei , Li Jian , Yin Shi
Published: October 2022

Cumulus granulosa cells (CGCs) are a type of important ovarian somatic cells that carries out various functions related to oogenesis, follicular development and embryogenesis. The study on the development and function of CGCs facilitates the understanding of reproductive regulation in female animals. Sirtuin 7 (SIRT7) is a member of the sirtuin family of NAD+‐dependent deacetylases mediating numerous biological processes. In this study, we detected the localization of SIRT7 in yak ovaries as well as explored the function of SIRT7 in yak CGCs. The results revealed that the SIRT7 protein was mainly localized in the cytoplasm of oocytes, granulosa cells and theca cells. The knockdown of SIRT7 in yak CGCs repressed cell proliferation and impacted the expressions of several apoptosis‐related genes. Furthermore, oestrogen synthesis was also inhibited in SIRT7‐deficient yak CGCs. The expressions of several sterogenesis‐related genes decreased significantly following SIRT7 knockdown. In addition, the lack of SIRT7 in yak CGCs resulted in decreased levels of the TGFB/SMAD family members TGFB1, TGFBR1 SMAD2 and SMAD3. Moreover, the activation of the TGFB/SMAD pathway by adding TGFB/SMAD pathway activator SRI‐011381 partially rescued the level of oestrogen secreted by SIRT7‐deficient yak CGCs, as well as the expressions of steroidogenesis‐related genes NR5A1 and CYP19A1. This research is the first to focus on the role of SIRT7 in yak ovary, and the outcomes offer new insights into the mechanism governing yak reproduction.
Planting time, first‐year mowing, and seed mix design influence ecological outcomes in agroecosystem revegetation projects
Authors: Glidden Alec J. , Sherrard Mark E. , Meissen Justin C. , Myers Mark C. , Elgersma Kenneth J. , Jackson Laura L.
Published: October 2022

The conversion of tallgrass prairie to agriculture has negatively affected provisioning of ecosystem services. Successful restoration of ecosystem services could depend on management decisions applied during revegetation projects. We examined the effects of three management decisions (seed mix design, planting time, and first‐year mowing) on targeted ecosystem services (erosion control, weed resistance, and pollinator resources). We tested three seed mixes of varying diversity and grass‐to‐forb seeding ratios: Economy mix (21 species, 3:1 grass:forb), Pollinator mix (38 species, 1:3), and Diversity mix (71 species, 1:1). We established plots at two planting times (dormant‐season and spring) with or without first‐year mowing. To assess ecosystem services, we measured stem density, canopy cover, and floral density and richness of sown species in the second year after planting. The Economy mix had the highest stem density and cover but lowest floral density and richness. The Pollinator mix had the lowest stem density and cover but highest floral density. The Diversity mix had comparable stem density and cover to the Economy mix and comparable floral density and richness to the Pollinator mix. Mowing accelerated native plant establishment in all seed mixes. Dormant‐season planting improved establishment of spring and fall forbs and favored cool‐season graminoids over warm‐season grasses. All three management decisions influenced ecosystem outcomes, and comparison to a previous study revealed these effects to be robust to variation in site and climatic conditions. We recommend a diverse, balanced seed mix design, first‐year mowing, and dormant‐season planting to improve multifunctionality of conservation projects.
Marine Vegetation Management Strategies: a framework for estuary wide prioritization of protection and rehabilitation
Authors: Asbridge Emma , Dwyer Patrick
Published: October 2022

Intertidal systems are constrained by landscape morphology. Where these systems do occur, they often experience a wide range of anthropogenic impacts, further exacerbated by sea‐level rise (SLR). By mapping natural morphological constraints, anthropogenic impacts and modeled SLR, at an estuary‐wide scale the Marine Vegetation Management Strategies (MVMS) identify and prioritize sites and interventions that could address key threats and risks to the system enabling rehabilitation. Development of MVMS is part of an initiative within the broader New South Wales (NSW) state government's Marine Estate Management Strategy to deliver healthy coastal habitats. The MVMS are being developed to take a policy of “no net loss of key fish habitats” toward more active management of intertidal systems that maximize and sustain the ecosystem values and services. Spatial indicators were developed for a pilot estuary (Tweed River) to map and quantify “macrophyte potential” which is defined as the capacity for macrophytes (mangrove and saltmarsh) to deliver ecosystem services now and into the future (under scenarios of SLR). The approach incorporates datasets which indicate the geophysical nature of the landscape, anthropogenic exposure, and vulnerability to SLR. This strategic science‐based approach is being rolled out across coastal NSW, with the mapping products and associated resources identified as key tools to assist in the adopting of a more integrated approach to managing coastal wetlands.
Role of skin autofluorescence in managing renal and cardiac diseases in outpatient dermatology
Authors: Etaee Farshid , Naguib Tarek , Goldust Mohamad , Daveluy Steven , Maibach Howard
Published: October 2022

Introduction

The accumulation of tissue‐advanced glycation end products in skin results from complex and consecutive reactions and can be measured by skin autofluorescence (SAF) reader devices. This overview discusses studies evaluating the utilization of SAF in screening renal and cardiac disease.

Materials and methods

Literature search was performed using Google Scholar, PubMed, Springer, Ovid, and ScienceDirect.

Results

SAF was an independent predictor of progression of chronic kidney disease (CKD) and was elevated in subjects on hemodialysis and peritoneal dialysis. Furthermore, SAF was significantly associated with cardiovascular events, cardiovascular mortality, and all‐cause mortality in CKD patients. Other studies revealed a correlation between SAF and arterial stiffness, vascular damage, and subclinical atherosclerosis. A vegetarian diet was associated with lower SAF levels, whereas malnutrition was correlated with higher levels and increased mortality.

Conclusions

SAF measurement may be useful in managing renal and cardiac disease. Future studies are needed to clarify the specific role of SAF in the management of CKD and its noninvasive office utilization to identify comorbidities in inflammatory diseases, such as psoriasis.
BAHD acyltransferase induced by histone deacetylase inhibitor catalyzes 3‐O‐hydroxycinnamoylquinic acid formation in bamboo cells
Authors: Nomura Taiji , Yoneda Akari , Kato Yasuo
Published: October 2022

Suspension‐cultured cells of a bamboo species (Bambusa multiplex; Bm) produce 3‐O‐feruloylquinic acid (3‐FQA) and 3‐O‐p‐coumaroylquinic acid (3‐pCQA) by treatment with the histone deacetylase inhibitor suberoyl bis‐hydroxamic acid (SBHA). Acyltransferases catalyzing the formation of 5‐O‐hydroxycinnamoylquinic acid esters by transesterification from hydroxycinnamoyl‐CoAs to the C‐5 hydroxy group of quinic acid (hydroxycinnamoyl‐CoA:quinate hydroxycinnamoyltransferase, HQT) have been identified in the biosynthesis of chlorogenic acids and monolignols; however, an HQT that catalyzes the acylation of the C‐3 hydroxy group of quinic acid has not been identified previously. In the present study, we purified a native HQT from SBHA‐treated Bm cells. The purified enzyme preferentially accepted feruloyl‐/p‐coumaroyl‐CoAs as acyl‐donors and quinic acid as the acyl‐acceptor, and the enzyme specifically formed 3‐FQA and 3‐pCQA but not 5‐O‐hydroxycinnamoylquinic acid esters or esters with shikimic acid. A cDNA (BmHQT1) encoding this HQT was isolated. Although BmHQT1 is a phylogenetically unique member of the BAHD acyltransferase superfamily that does not cluster with other HQTs, functional characterization of the recombinant enzyme verified that BmHQT1 catalyzes the regiospecific formation of 3‐O‐hydroxycinnamoylquinic acid esters. Transcript levels of BmHQT1 markedly increased in Bm cells cultured in the presence of SBHA. Moreover, elevated acetylation levels of histone H3 were observed in the coding region of BmHQT1 in the presence of SBHA, indicating that the induced accumulation of 3‐FQA/3‐pCQA by SBHA is caused by transcriptional activation of BmHQT1 by the action of SBHA as a histone deacetylase inhibitor. The results demonstrate the utility of HDAC inhibitors for discovery of cryptic secondary metabolites and unknown biosynthetic enzymes.
ZmLBD5, a class‐IILBD gene, negatively regulates drought tolerance by impairing abscisic acid synthesis
Authors: Feng Xuanjun , Xiong Jing , Zhang Weixiao , Guan Huarui , Zheng Dan , Xiong Hao , Jia Li , Hu Yue , Zhou Hanmei , Wen Ying , Zhang Xuemei , Wu Fengkai , Wang Qingjun , Xu Jie , Lu Yanli
Published: October 2022

Lateral organ boundaries domain (LBD) proteins are plant‐specific transcription factors. Class‐I LBD genes have been widely demonstrated to play pivotal roles in organ development; however, knowledge on class‐II genes remains limited. Here, we report that ZmLBD5, a class‐II LBD gene, is involved in the regulation of maize (Zea mays) growth and the drought response by affecting gibberellin (GA) and abscisic acid (ABA) synthesis. ZmLBD5 is mainly involved in regulation of the TPS‐KS‐GA2ox gene module, which is comprised of key enzyme‐encoding genes involved in GA and ABA biosynthesis. ABA insufficiency increases stomatal density and aperture in overexpression plants and causes a drought‐sensitive phenotype by promoting water transpiration. Increased GA1 levels promotes seedling growth in overexpression plants. Accordingly, CRISPR/Cas9 knockout lbd5 seedlings are dwarf but drought‐tolerant. Moreover, lbd5 has a higher grain yield under drought stress conditions and shows no penalty in well‐watered conditions compared to the wild type. On the whole, ZmLBD5 is a negative regulator of maize drought tolerance, and it is a potentially useful target for drought resistance breeding.
Crofton formulas in pseudo-Riemannian space forms
Authors: Bernig Andreas , Faifman Dmitry , Solanes Gil
Published: October 2022

Crofton formulas on simply connected Riemannian space forms allow the volumes, or more generally the Lipschitz–Killing curvature integrals of a submanifold with corners, to be computed by integrating the Euler characteristic of its intersection with all geodesic submanifolds. We develop a framework of Crofton formulas with distributions replacing measures, which has in its core Alesker's Radon transform on valuations. We then apply this framework, and our recent Hadwiger-type classification, to compute explicit Crofton formulas for all isometry-invariant valuations on all pseudospheres, pseudo-Euclidean and pseudohyperbolic spaces. We find that, in essence, a single measure which depends analytically on the metric, gives rise to all those Crofton formulas through its distributional boundary values at parts of the boundary corresponding to the different indefinite signatures. In particular, the Crofton formulas we obtain are formally independent of signature.
Investigating the Origins of Cyclic Variability in Internal Combustion Engines Using Wall-Resolved Large Eddy Simulations
Authors: Wu Sicong , Patel Saumil S. , Ameen Muhsin M.
Published: October 2022

Modern internal combustion engines (ICE) operate at the ragged edge of stable operation characterized by high cycle-to-cycle variations (CCV). A key scientific challenge for ICE is the understanding, modeling, and control of CCV in engine performance, which can contribute to partial burns, misfire, and knock. The objective of this study is to use high-fidelity numerical simulations to improve the understanding of the causes of CCV. Nek5000, a leading high-order spectral element, open source code, is used to simulate the turbulent flow in the engine combustion chamber. Multicycle, wall-resolved large-eddy simulations (LESs) are performed for the General Motors (GM), Transparent Combustion Chamber (TCC-III) optical engine under motored operating conditions. The mean and root-mean-square (rms) of the in-cylinder flow fields at various piston positions are validated using particle image velocimetry (PIV) measurements during the intake and compression strokes. The large-scale flow structures, including the swirl and tumble flow patterns, are analyzed in detail and the causes for cyclic variabilities in these flow features are explained. The energy distribution across the different scales of the flow are quantified using one-dimensional (1D) energy spectra, and the effect of the tumble breakdown process on the energy distribution is examined. The insights from this study can help us develop improved engine designs with reduced cyclic variabilities in the in-cylinder flow leading to enhanced engine performance.
High-Fidelity Energy Deposition Ignition Model Coupled With Flame Propagation Models at Engine-Like Flow Conditions
Authors: Kazmouz Samuel J. , Scarcelli Riccardo , Kim Joohan , Cheng Zhen , Liu Shuaishuai , Dai Meizhong , Pomraning Eric , Senecal Peter K. , Lee Seong-Young
Published: October 2022

With the heightened pressure on car manufacturers to increase the efficiency and reduce the carbon emissions of their fleets, more challenging engine operation has become a viable option. Highly dilute, boosted, and stratified charge, among others, promise engine efficiency gains and emissions reductions. At such demanding engine conditions, the spark-ignition process is a key factor for the flame initiation propagation and the combustion event. From a computational standpoint, there exist multiple spark-ignition models that perform well under conventional conditions but are not truly predictive under strenuous engine operation modes, where the underlying physics needs to be expanded. In this paper, a hybrid Lagrangian–Eulerian spark-ignition (LESI) model is coupled with different turbulence models, grid sizes, and combustion models. The ignition model, previously developed, relies on coupling Eulerian energy deposition with a Lagrangian particle evolution of the spark channel, at every time-step. The spark channel is attached to the electrodes and allowed to elongate at a speed derived from the flow velocity. The LESI model is used to simulate spark ignition in a nonquiescent crossflow environment at engine-like conditions, using converge commercial computational fluid dynamics (CFD) solver. The results highlight the consistency, robustness, and versatility of the model in a range of engine-like setups, from typical with Reynolds-averaged Navier–Stokes (RANS) and a larger grid size to high fidelity with large-eddy simulation (LES) and a finer grid size. The flame kernel growth is then evaluated against Schlieren images from an optical constant volume ignition chamber with a focus on the performance of flame propagation models, such as G-equation and thickened flame model, versus the baseline well-stirred reactor model. Finally, future development details are discussed.
Experimental Investigation of Friction Damping in Blade Root Joints
Authors: Botto Daniele , Cuccovillo Federica , Iannotti Veronica
Published: October 2022

The design of disk assemblies requires the capability to predict their dynamic behavior. To achieve this objective, knowledge of friction damping on the contact between blade and disk is of paramount importance. This paper proposes an experimental technique to measure the loss factor and the dynamics, in terms of natural frequencies, of blade-disk attachment. The free decay is used to infer the dynamic parameters from dummy blades. The identification method is based on the Hilbert transform that allows extracting the dynamic parameters from nonlinear system. This paper shows the test rig utilized in the experimental analysis and details the excitation system used to displace the dummy blade. This system must be a real or a “virtual” noncontact system to avoid injecting external damping into the blade under test. Tests were performed on both a dovetail and a fir-tree type attachment. On the dovetail, tests were performed both with dry contact surfaces and with contact surfaces covered by a film of lubricant to achieve a low coefficient of friction. This low coefficient of friction better simulates dry surfaces at high temperatures, as friction coefficients decrease with temperatures. This paper presents the results obtained on the first and second bending mode. The experimental results show the loss factor and the natural frequency for different axial loads. The measured loss factor depends on the amplitude of vibrations. As predicted with theoretical analyses the loss factor shows a maximum then approaching zero for large amplitude of vibrations. As a rule, it decreases with increasing centrifugal loads.
A Photoconductance Mechanism for Oil Shale Pyrolysis Process Detection
Authors: Miao Xinyang , Wu Haoqiang , Liu Zhi , Li Yudong , Yu Yawen , Zhan Honglei , Zhao Kun
Published: October 2022

Kerogen in oil shale plays a crucial part in the shale oil and gas generation. Here, photoconductive measurement was used to evaluate the decomposition process of Huadian oil shale. The photoconductivity of the semi-coke is a clear indicator of different pyrolysis stages, including moisture evaporation, primary pyrolysis of kerogen, decomposition of asphalt monomer, and mineral decomposition. Furthermore, the distribution model of electrical resistance (R) and photoconductance (ΔI) for Huadian oil shale is plotted, indicating an inverse proportion between R and ΔI. We believe that the photoconductive measurement will be a valuable means for the nondestructive characterization of oil shale pyrolysis, which is helpful to optimize the comprehensive utilization of this unconventional resource.
Efficient Test Method for Determining the Thermomechanical Fatigue Lifetime of Additively Manufactured Combustion Chamber Tiles Under Component-Related Conditions
Authors: Schlesinger Michael , Schackert Sophie , Sikorski Igor , Mathiak Georg
Published: October 2022

Combustion chamber tiles of aircraft engines are subject to locally high thermomechanical fatigue (TMF) loading during flight operations. The TMF loading in these components results in a cyclic bending load over the wall thickness. Additional stress concentrations occur at geometric features such as fillets or effusion cooling holes. Thus complex loading conditions arise that cannot be reliably assessed using conventional material database and computational design methods. In the context of this article, a new test method is presented that consists of a bending test rig for applying component-related loading conditions to corresponding specimens, here called subelements, that represent significant geometric, lifetime-limiting features of the component. In various test series on additively manufactured subelements, geometric, manufacturing, thermal, mechanical and time-dependent parameters are investigated concerning their influence on fatigue crack growth and lifetime. The results from these tests are compiled in a database, which is used to validate an advanced computational assessment approach for crack growth and lifetime accounting for stress gradients in the depth direction due to the bending and along the surface due to possible geometric features. The method can be applied to component geometries such as combustion chamber tiles using a mechanical finite element analysis (FEA) followed by postprocessing steps to increase reliability of lifetime predictions.
Numerical Investigation of an Automotive Axial Fan: A Comparison Among Different CFD Software Packages and Experimental Validation
Authors: Aldi Nicola , Casari Nicola , Oliani Stefano , Pinelli Michele , Mollica Enrico , Menichini Filippo
Published: October 2022

Electrical and fossil fuel powered vehicles require to reject some form of heat produced as a byproduct of their operating principle. This task is performed by radiators, typically equipped with axial flow fans to maximize the specific processed flow rate. These fans, as well as all the other fans that typically equip the vehicles (e.g., for HVAC purposes), are required to be very efficient and to produce a minimum level of noise.

In this framework it is of crucial importance to adopt all the tools that can help in understanding the source of inefficiency and noise. This work presents the adoption of Computational Fluid Dynamics (CFD) as a possible tool for the investigation of the fluid dynamics of an axial flow fan.

In order to let CFD become routinely employed, a sequence of validation steps is required by industries. In this work, two different CFD tools (ANSYS-CFX and OpenFOAM-v2006) are employed and the results of the investigation are compared to experimental data for assessing the reliability and the accuracy of each of these tools. Experimental data are obtained with two test benches: one build in compliance with ANSI/AMCA standards for airflow performance evaluation and one ad hoc developed for PIV measurements (i.e. flow field visualization). The capability of the CFD softwares of correctly replicating the fan performance and flow field even in this complex set-up (due to the loose constraints of the fluid flow) is shown both with steady and transient simulations.
Topological Optimisation and 3d Printing of a Bladed Disc
Authors: Barreau Vincent , Denimal Enora , Salles Loic
Published: October 2022

In turbomachinery, components are pushed to their limits to meet more stringent specifications in order to increase their performances. In this context, structural topology optimisation is a promising technology as it improves substantially the mechanical properties while drastically reducing the mass. With the coming of additive manufacturing, optimised geometry can be manufactured making this technology even more attractive. The aim of this work is to investigate the potential of topology optimisation to optimise a full bladed disc to improve its dynamic performances in terms of mass, stress and modal coincidences.

The topology of a 3D-Finite Element Model of an academic bladed disc is optimised in this work and experimental validation is expected. So first, the disc is designed to fit in the test-rig and the mechanical integrity of the 3D-printed disc is experimentally verified. Second, the topology of the blades is optimised. Based on a trial-and-error process, the appropriate topology optimisation problem properties for vibration optimisation are identified. Thus, adding a static force at the blade tip forces a better material distribution over the domain and increases the blade stiffness. To minimise the number of coincidences, a numerical strategy based on iterative topology optimisation simulations is proposed to identify the correct set of frequential constraints. Final results show that the mass of the blade is reduced up to 32% and the number of frequential coincidences is reduced from 11 to 4. Final geometries are 3D-printed and mounted on the disc.
Film Cooling Hole Shape Effects on Turbine Blade Heat Transfer – Part II: Effects of Mass Flow Rate and Unsteadiness
Authors: Sperling Spencer , Christensen Louis , Mathison Randall , Aksoy Hakan , Liu Jong , Nickol Jeremy
Published: October 2022

To provide a detailed analysis of film cooling in a turbine environment, this study incorporates experimental and computational research performed on a rotating high pressure turbine stage. The turbine blades include rows of three different film cooling hole shapes investigated at several different cooling mass flow rates supplied to the rotor. Film cooling hole shapes include round, fan, and advanced anti-vortex shapes, and the performance of these cooling systems installed on the rotating blades are evaluated on time-averaged and unsteady bases.

Film cooling hole shape and coolant mass flow provide different cooling benefits in different areas of the blade. Across the pressure surface, leading edge, and suction surface, advanced film cooling holes show the most response to changing coolant mass flow, and typically have the highest film effectiveness at the highest film cooling flow rate.

Film cooling jets experience similar motions regardless of hole shape. Unsteady pressure gradients across the film cooling hole outlets on the pressure surface cause cooling jet motion. Fan and Advanced shaped holes cause lateral spread of cooling gas on a steady basis, and due to the increased lateral spread, a larger region on the pressure surface receives consistent film coverage. On a time-average basis, this results in much more lateral spread and increased film coverage for shaped film cooling holes.

The results of this study help identify the performance of shaped film cooling holes in turbine environments. The response of different hole shapes to unsteadiness has a significant impact on the time average film cooling coverage. Additionally, the hole shapes respond differently to increased levels of coolant mass flow rate and provide different degrees of film cooling coverage on different parts of the blade. An increased understanding and appreciation of the unsteady performance of various film cooling geometries is a foundational piece of continued technology development.
Effects on Sustainability by Redesign of a 1° Stage Gas Turbine Nozzle Ring From Investment Casting to Additive Manufacturing: A Life Cycle Environmental Impact Comparison
Authors: Fantaccione Luca , Serra Angela , Buia Giulio , Bartocci Pietro , Gandini Sergio , Fantozzi Francesco
Published: October 2022

Energy companies are committing to protect the environment and reducing their product carbon footprint. To accomplish these objectives, they need to establish their baseline, including the life cycle emissions of key products and services. The life cycle emissions assessment will help to support customers and suppliers, many of which have set their own carbon footprint reduction targets, in finding opportunities to reduce their own environmental impact.

The purpose of this study is to compare the environmental impact of two manufacturing processes, namely Additive Manufacturing (AM) and Investment Casting (IC), for the production of a 1° stage gas turbine nozzle ring in order to determine which method is the most sustainable on the Life Cycle. AM technologies brought to the world new design possibilities which become very useful for those items whose production rate decreases due to a drop in demand or a suspended production. In this case study, which considers a serviced Gas Turbine, the production volume is very low compared to the standard production of a gas turbine. For this reason, AM revealed to be a key strategy for the investigated product for environmental, cost and lead time sustainability.

The LCA is conducted under Cradle-to-Gate boundaries, hence it investigates every energy/material input and output from the raw materials extractions, to the production of the good at the gate of the company ready for shipping.

Raw material extraction, powder atomization, machining, finishing, and coating phases are included into the analysis. The choice of the manufacturing strategy requires different materials and different suppliers are involved into the manufacturing chain, which means also differences in transportation and sources for electricity production.
Development of an Open-Source Autonomous CFD Meta-Modeling Environment for Small-Scale Combustor Optimization – Part II
Authors: Briones Alejandro M. , Rankin Brent A.
Published: October 2022

This work presents an improved open-source autonomous CFD meta-modeling environment (OpenACME) for small-scale combustor design optimization. OpenACME couples several object-oriented programming open-source codes for CFD-assisted engineering design meta-modeling. OpenACME is fully automated and can be used in PC workstations or HPC clusters. OpenACME uses a global metaheuristic optimization algorithm based on multiple-objective evolutionary algorithm (i.e., NSGA-II). An initial design population is first computed with Latin Hypercube Sampling and subsequent iterations generate offspring based on tournament mating, uniform crossover, and polynomial mutation. OpenACME is capable of computing multiple parallel CFD design points concurrently, speeding up the meta-simulations. The CFD are based on steady-state, incompressible, three-dimensional simulations with multi-phase k-ω SST RANS and “frozen” flamelet progress variable (FFPV) combustion model. There are fifteen design variables. There are three meta-simulations. The meta-simulations report Pareto Frontier from which optimum designs can be selected based on thermodynamic cycle requirements. Conjugate heat transfer provides the most realistic liner temperature and combustor performance. Acritical is still recommended as a cost function when liner durability is a concern. OpenACME demonstrated to be a viable tool for combustor design optimization.
Flow Separation Modelling Dowstream of Military Low Pressure Compressors
Authors: Ruiz Domingo Javier , Pieyre Amanda
Published: October 2022

In military turbofan architectures, a flow separation is operated downstream the Low Pressure Compressor (LPC), mainly to increase the propulsive efficiency and to cool down and provide oxygen to the reheat channel. The flow is separated into a primary flow that goes through the high-pressure components and combustion chamber and a secondary flow which remains cold and is mixed with the primary flow before the reheat. The Bypass Ratio (BPR) represents the mass flow rate ratio between secondary and primary flow. During engine operation from high to low power, the BPR varies drastically. Moreover, current and future military engines present many variable geometries to improve their maneuverability, and the BPR can strongly depend on the settings of these geometries. BPR variations lead to a shift in the LPC exit separation streamline and therefore to modifications on the thermodynamic conditions in both primary and secondary flows.

Existing methods usually perform the separation on the overall LPC map using corrective coefficients. The aim of this work is to provide an alternative method to model the effects of the shifting of the separation line on the thermodynamic parameters. Instead of using an overall compressor map, this method uses two compressor maps, one for the inner and one for the outer stream, at a reference BPR. When the BPR is different from this reference value, corrections are applied to the reference maps. The main hypothesis of this method is that the aerodynamics of the LPC is uncoupled from the splitter, meaning that the total temperature and total pressure profiles do not depend on the BPR. Analytical profiles are used from hub to tip for work and losses coefficients parameters. The analytical profiles are chosen to better fit the actual profiles in the working BPR range of interest. This method is designed to be included in a performance model. The method presented is validated on LPC Rig test and CFD data.
Vortex Unsteadiness in the Endwall Region of a High-Lift Low-Pressure Turbine Passage
Authors: Marks Christopher R. , Fletcher Nathan , Sondergaard Rolf
Published: October 2022

Three-dimensional vortical structures within the endwall region of turbine passages directly affect the aerodynamic efficiency and heat transfer characteristics of the turbine. Interactions between the vortical endwall structures and the suction surface flow have been shown to be a significant source of loss generation through passages. One dominant vortex extends from the leading edge junction region of the blade across the passage, where it interacts with the flow along the suction surface of the adjacent blade. In high-lift low-pressure turbine cascade passages, the vortical structure intermittently loses coherence and exhibits unsteady variations of strength and position as it extends across the passage. The present paper details the temporal behavior through high-speed measurements in a low speed linear cascade of high-lift low-pressure turbine blades. Stereoscopic particle image velocimetry measurements in the passage are used to evaluate the unsteady behavior of the vortex. Space-time iso-surface plots of Q-criterion clearly show the evolution of the vortex over time. Analysis of the data reveals the various time scales of fluctuations in strength and position. Comparisons of the temporal fluctuations in the high-lift turbine passage are made with similar phenomena found in canonical junction flow papers in the literature. Key findings support the hypothesis that in-passage vortex unsteady characteristics near the endwall are influenced by leading edge junction flow dynamics, and provide additional insight into the unsteady endwall flow physics that are necessary to further the development of endwall loss reduction techniques.
Effect of Temperature and Velocity on Microparticle Erosion/Deposition Into Environmental-Barrier-Coated CMC for Aeroengines
Authors: Okita Yoji , Suzuki Masaya , Yamane Takashi , Hasegawa Jun , Mizokami Yosuke , Nakamura Takeshi
Published: October 2022

Ceramic matrix composites (CMCs), especially SiC/SiC, have garnered significant attention owing to their remarkable mechanical properties at higher temperatures. For protection of the substrate from oxidation, the SiC/SiC CMCs inherently require environmental barrier coating (EBC). Because aeroengines must function under a wide range of conditions and environments, the coated CMC must be sufficiently resistant to various damage modes. Among these, the effect of microparticles is one of the limiting factors for durability and performance of components, particularly when the engine is operated in dusty areas.

The main goal of this experimental research is to investigate and determine the surface damage behaviour of the coated CMC caused by micro sand particles. The data were surveyed across a fairly broad range of exposed temperatures and velocities, and covered conditions relevant to advanced hot section designs. In the experiments, silica or alumina sand entrained in the gas stream was jet-blasted from the nozzle and then impinged on the target CMC+EBC coupon.

Owing to the broad testing range, the damage mode and extent of damage varied considerably by condition. The obtained data were then reorganised and compared with several previously proposed particle impact models. This is to first understand and obtain a complete picture of all the probable consequences in the expected design and off-design conditions, and second, to determine the validity of, and deviations from the conventional modelling with the present CMC+EBC material, which will be useful in the next component design phase.
Effect of Channel Size on Air-Cooling Performance in Interior Permanent Magnet (IPM) Motor Driving Aviation Fans at High Altitude
Authors: Ito Yu , Watanabe Toshinori , Seki Naoki , Hirakawa Karin , Inoue Tomoya , Himeno Takehiro
Published: October 2022

To enhance worldwide environmental conditions, the air transport industry must drastically reduce carbon dioxide emissions. Electrification of aircraft propulsion systems is one way to meet this demand. In particular, the focus is on obtaining single-aisle aircraft with partial turboelectric propulsion and approximately 150 passenger seats by the 2030s. To develop a single-aisle aircraft with partial turboelectric propulsion, an air-cooled interior permanent magnet (IPM) motor with an output of 2 MW is desired. One of the most difficult problems in air cooling is that air-cooling performance decreases with increasing altitude because the air density decreases. To investigate the effect of altitude on air-cooling performance in the IPM motor, the authors formulated mathematical system equations to describe heat transfer inside the target air-cooled IPM motor, and mathematical analytical solutions were obtained. The most severe condition is the top-of-climb condition. For this condition, a designer should choose cooling air mass flow rates that keep the temperature of the permanent magnets below the maximum temperature limit of 100 °C and the temperature of the coils below the maximum temperature limit of 250 °C. Here, the sizes of the air-cooling channels strongly affect air cooling with the IPM motor. In this paper, the authors briefly review the mathematical formulations and their solutions, investigate the effect of channel size on air-cooling performance in an IPM motor, and explore the optimum configuration and settings for the air cooling channels.
The Nonlinear Thermoacoustic Eigenvalue Problem and Its Rational Approximations: Assessment of Solution Strategies
Authors: Merk Moritz , Buschmann Philip E. , Moeck Jonas P. , Polifke Wolfgang
Published: October 2022

Nonlinear eigenvalue problems (NLEVPs) arise in thermoacoustics by considering the temporal evolution of small perturbations in the relevant governing equations. In this work, two solution strategies are compared: (i) a contour-integration-based method that guarantees to provide all eigenvalues in a given domain and (ii) a method that approximates the NLEVP by a rational eigenvalue problem, which is generally easier to solve. The focus lies on numerical speed, the completeness of the computed spectrum, and the appearance of spurious modes, i.e., modes that are not part of the original spectrum but appear as a result of the approximation. To this end, two prototypical thermoacoustic systems are considered: a single-flame Rijke tube and an annular model combustor. The comparison of both methods is preceded by a detailed analysis of the user-defined input parameters in the contour-integration-based method. Our results show that both methods can resolve all types of considered eigenvalues with sufficient accuracy for applications. However, the recast linear problem is overall faster to solve and allows a priori precision estimates — unlike the contour-integration-based method. Spurious modes as a by-product of the NLEVP approximation are found to play a minor role, and recommendations are given on how to eliminate them.
Comparison of Experimental and Numerical Local Rotational Heat Transfer Effects in a Two-Pass Cooling Channel Configuration
Authors: Gutiérrez de Arcos David , Waidmann Christian , Poser Rico , von Wolfersdorf Jens , Jäppelt Bernhard
Published: October 2022

A two-pass internal cooling channel under the influence of rotation is experimentally and numerically investigated. Steady-state numerical simulations support the experimental method, which is based upon the temperature measurement with thermochromic liquid crystals (TLC). Moreover, the transient TLC experiment serves as a basis for validation of the numerical setup. Reynolds number is 15000, Rotation number is increased up to 0.50 and the cooling channel is investigated at three different angles of attack. Results are locally evaluated as normalized Nusselt number ratios of the rotating to its corresponding non-rotating case. With this, the sole effect of rotation on heat transfer can be disclosed. Histograms of normalized Nusselt number ratio allow for drawing conclusions on the local effects of rotation on heat transfer enhancement.
Compression Applications for Carbon Reduction
Authors: Kurz Rainer , Lubomirsky Matt , McLorg Gregory
Published: October 2022

A In the context of carbon reduction efforts, discussions evolve around hydrogen compression, as well as compression requirements related to CO2 capture, transportation and sequestration. In this paper, compression requirements for these applications are discussed.

The use and creation of hydrogen imposes specific questions on the use of centrifugal compressors. These questions involve the requirement to compress hydrogen for significant pressure ratios, and the impact of transporting hydrogen in pipelines, or by other means. Part of the discussion is also the location of blue hydrogen production versus green hydrogen production, based on the fact that transport of CO2 or natural gas requires less energy than the transport of hydrogen.

Further, carbon sequestration by capturing, transporting and sequestering CO2 from the exhaust of fossil fired power plants, from the generation of blue hydrogen, or the generation of Ammonia is discussed. Compression duties include the compression from capture pressure to pipeline pressure, the boost compression as part of the pipeline transport, and the compression required to sequester the CO2. Issues addressed in this part include the relative effort required based on the CO2 concentration in the exhaust, and methods to compress CO2 and CO2 mixtures from close to atmospheric pressure to pipeline pressure.

In this discussion, the option of transporting hydrogen to a power plant versus transporting natural gas to said power plant, and transporting captured CO2 back to a sequestration site, is evaluated, and the conclusion is supported with data.
The Effect of Partial-Load Operation on a Gas Turbine Compressor of an Advanced Combined Cycle Power Plant
Authors: Hagita Yasuharu , Miyazawa Hironori , Furusawa Takashi , Yamamoto Satoru , Yonezawa Koichi , Umezawa Shuichi , Ohmori Shuichi , Suzuki Takeshi
Published: October 2022

Gas turbine combined cycle (GTCC) power plants daily undergo start-up, shutdown and partial-load operations to maintain load invariance of electric power supply. The off-design conditions in this process may give rise to unexpected and unsteady flow behavior in the gas turbine, resulting in fatigue failure. JERA Co. Inc. currently operates gas turbines at many advanced combined cycle (ACC) power plants using a start-up and a partial-load operations. During the start-up procedure, some machine vibrations were reported at the ACC power plant when acoustic emission (AE) measurements were applied to the gas turbine compressor. A small crack in the first-stage stator blade was found at another unit during the overhaul. The partial-load operation may be in a similar condition to that in the startup procedure.

This study elucidated the cause of machine vibration measured in an actual gas turbine compressor of an ACC power plant using full-annulus flow computation to indicate the possibility of blade failure. The full-annulus unsteady flows through the inlet guide vanes (IGV) and 1.5 rotor and stator stages in the compressor were simulated. The frequency of the simulated vibration was compared with that of the natural vibration of the blades, which was obtained by conducting eigenvalue analysis. The results for the partial-load condition captured an abnormal vibration resulting from a rotating stall. The rotating stall frequency closely matched the second-mode frequency of the first-stage stator blade’s natural vibration. This result suggests that the partial-load condition could be related to the cause of the blade failure due to the blade vibration.