bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational and Experimental Assessment of a MW-Scale Supercritical CO2 Compressor Operating in Multiple Near-Critical Conditions
Authors: Toni Lorenzo , Bellobuono Ernani Fulvio , Valente Roberto , Romei Alessandro , Gaetani Paolo , Persico Giacomo 
Published: October 2022

Abstract
The present work illustrates the results of a wide experimental campaign in the frame of the EU-funded project sCO2-Flex, focused on the investigation of a MW-scale sCO2 compressor operating in plant-representative conditions. The experimental tests are carried out for four temperature levels between 304.15K and 309.15K at a fixed pressure (79.79 bar), hence covering an extended thermodynamic region close to the critical point. The experimental results are thoroughly discussed with the support of steady computational fluid-dynamics simulations, assuming homogeneous flows and thermodynamic equilibrium for the two-phase flow description. Changing the upstream total state, two peculiar variabilities in the compressor pressure ratio and choked-flow rate are experimentally and computationally observed. While the former is mainly related to the single-phase flow thermodynamics, the latter originates from the onset of two-phase flows. As the simulations predict the experimental choking with a maximum error of 3%, the corresponding two-phase speed of sound is analyzed to infer the underlying equilibria between phases. It is found that, for the tested conditions, two-phase flows quickly achieve thermodynamic equilibrium, and non-equilibrium or meta-stable effects arguably play a marginal role in the process.
A Reduction Technique for the Calculation of the Forced Response of Bladed Disks in Presence of Contact Mistuning at Blade Root Joints
Authors: Pinto Valeria , Battiato Giuseppe , Firrone Christian M. 
Published: October 2022

Abstract
The effect of differences in nominally equal sectors of a bladed disk (mistuning) is a well-known problem for designers since the forced response may show localized amplification of the blade response with respect to a cyclically symmetric (tuned) configuration. In order to perform a large number of simulations in a reasonable amount of time to characterize the highest blade response, corresponding to the worst mistuning pattern, reduction techniques have been developed where the mistuning is introduced directly in compact, Reduced Order Model (ROM) obtained from very large finite element (FE) models. Typically, mistuning is introduced in the ROM in terms of natural frequency perturbations of the blade; nevertheless, a better insight is specifically required in order to correlate mistuning to a specific source (geometrical, material, contact mistuning).
In this paper, a reduction technique is presented to take into account mistuning due to the contact uncertainties at the blade root joint, which can be caused by design tolerances, manufacturing process, assembly procedures, wear. The technique takes its basis from the Craig-Bampton Component Mode Synthesis applied to the uncoupled blade and disk sector, which is typically included in most of the FE software for an easy implementation in standard industrial practice. The full set of master degrees of freedom at the random contacts are purposely reduced using an optimal local modal basis based on the Gram-Schmidt Interface technique developed by the authors.
Experimental evidence of actual uncertain contact obtained during joint pre-loading is used to find an appropriate base to represent typical contact patterns.
Performance of Additively Manufactured Internally Cooled Airfoils for Small Industrial Gas Turbines
Authors: Straub Doug , Ramesh Sridharan , Searle Matthew , Robey Edward , Floyd Tim , Roy Arnab , Ames Forrest E. 
Published: October 2022

Abstract
The purpose of this effort is to screen several internally cooled airfoil designs that could be fabricated when additive manufacturing becomes a viable alternative for industrial gas turbine applications. This effort is part of a larger effort to increase gas turbine performance for combined heat and power systems using additive manufacturing for advanced cooling designs. The baseline cooling configurations have been described previously and include a baseline vane and a baseline blade. The baseline vane is impingement cooled with pin-fins in the trailing edge. The baseline blade incorporates a combination of impingement, rib turbulators and pin-fin features. This paper will compare the one-dimensional cooling model described previously with experimental measurements in a conjugate intermediate temperature (650K) test facility at NETL. A double-wall internally cooled concept will also be described. A preliminary stress comparison for the double-wall concept relative to the baseline blade will be discussed. The one-dimensional cooling model predictions overpredict the experimentally measured overall cooling effectiveness. The differences between the model and the experiment, as well as comparisons between technology curves of the different cooling designs will be described.
Optimum Injector Parameters for Thermoacoustic Stability in a Multi-Nozzle Can Combustion System
Authors: Acharya Vishal 
Published: October 2022

Abstract
High-frequency transverse instabilities are an important concern in can combustor configurations. In these configurations which are typically operated with multiple injectors around a central injector, each injector is subjected to different parts of the acoustic mode shape and thus respond differently for the same instability mode. Recent work by the author has modeled the response of premixed flames to excitation by natural high-frequency transverse modes in a can combustor both in the center and outer nozzles. The stability of these acoustically non-compact flames was assessed using the Rayleigh criterion (Rayleigh Integral denoted as RI) and not the overall unsteady heat release as is the case for compact flames. Several key control parameters were studied, namely — flame angle, swirling strength, nozzle location. For non-axisymmetric modes such as the commonly occurring 1-T mode, both radial and azimuthal offsets of the nozzle location affected stability. The framework was applied to an optimization study to identify the optimal combination of parameters that minimizes RI for the different nozzles in the multi-nozzle system. In this study, a N-around-1 configuration was studied, and the results indicated that the different nozzles needed to be operated at different flame angles and swirl numbers to result in an overall minimum RI. However, the specific response of the different injectors was not considered. The helical mode distribution at each injector varies as we azimuthally go around the combustor’s injector distribution and thus the most amplified mode and the resulting flame response would be different. To minimize RI, it is important to determine the injector configurations that result in a hydrodynamic profile that minimizes the individual RI for each nozzle. The resulting relationship between the injector’s flow and local hydrodynamics can then be used in a hydrodynamics study of an individual injector so that the most optimal injector is chosen depending on its location in the combustor dump plane.
Use of Convolutional Neural Network Image Classification and High-Speed Ion Probe Data Towards Real-Time Detonation Characterization in a Water-Cooled Rotating Detonation Engine
Authors: Johnson Kristyn B. , Ferguson Donald H. , Nix Andrew C. 
Published: October 2022

Abstract
As rotating detonation engine (RDE) technologies progress in maturity, the importance of monitoring methods progressing towards development of active control becomes more critical. High-speed processing of experimental RDE data on a time scale approaching real-time diagnostics will likely only be accomplished through the use of machine learning. This study aims to develop and deploy a real-time monitoring technique which integrates flame image classification by a convolutional neural network (CNN) and ionization current signal analysis with the goal of determining detonation wave number, direction, frequency, and individual wave speeds throughout experimental RDE operational windows. Wave mode identification through single image CNN classification bypasses the need to evaluate sequential images and offers instantaneous identification of the wave mode present in the RDE annulus. The output of the existing CNN is utilized alongside a correlation of ion probe data to generate diagnostic outputs. The diagnostic acquires live data using a modified experimental setup as well as Pylon and PyDAQmx libraries within a Python data acquisition environment. Lab-deployed diagnostic results are presented across a variety of wave modes, operating conditions, and data quality, currently executed at 3–4 Hz with a variety of iteration speed optimization options to be considered as future work. These speeds exceed that of conventional techniques and offer a proven structure for real-time RDE monitoring, which will play a vital role in the development of active control, necessary for the extension of operational capabilities and RDE technology maturation toward industrial integration.
Evaluation of Adjoint Optimized Holes - Part I Baseline Performance
Authors: Gutierrez Daniel , Yoon Christopher , Furgeson Michael T. , Veley Emma M. , Bogard David G. , Thole Karen A. 
Published: October 2022

Abstract
With the advent of the use of additive manufacturing to build gas turbine components, the design space for new hole geometries is essentially unlimited. Recently, a computational adjoint based optimization method was used to design shaped film cooling holes fed by internal co-flow and cross-flow channels. The associated RANS computations predicted that the holes optimized for use with cross-flow (X-AOpt) and co-flow (Co-AOpt) would significantly increase adiabatic effectiveness. However, only the X-AOpt hole was tested experimentally in this previous study. Though the experimentally measured performance for this hole was much less than computationally predicted, it still had a 75% improved performance compared to the conventional 7-7-7 shaped hole. In the current study, the X-AOpt and Co-AOpt shaped holes were experimentally evaluated using measurements of adiabatic effectiveness and overall cooling effectiveness. Coolant was fed to the holes with an internal co-flow channel. For reference, experiments were also conducted with the baseline 7-7-7 shaped hole, and a 15-15-1 shaped hole (shown in a previous study to be the optimum expansion angles for a shaped hole). Furthermore, overall cooling effectiveness measurements were made with engine scale models to evaluate the performance of additively manufactured (AM) X-AOpt and Co-AOpt holes with a realistic metal build. Results from this study confirmed that the X-AOpt hole had a 75% increase in adiabatic effectiveness compared to the 7-7-7 shaped hole. However, the Co-AOpt hole had only a 30% increase in adiabatic effectiveness, substantially less than had been computationally predicted. Measurements of overall cooling effectiveness for the engine-scale models and the large-scale models followed similar trends.
Heat Load Parameter and Cooling Effectiveness On a Supercritical CO2 Stage One Vane With a Serpentine Internal Cooling Scheme
Authors: Olson Weston , Fernandez Erik , Vesely Ladislav , Khadse Akshay , Kapat Jayanta 
Published: October 2022

Abstract
Supercritical CO2 Brayton cycles are considered by some as the next evolution in power generation. The question of cooling effectiveness for hot gas path components arises for this topic. In this work, a stage one vane was designed with an internal cooling scheme which consisted of a turbulated three-pass serpentine which fed a trailing-edge pin fin bank with pressure-side cutback trailing-edge slot extraction. A conjugate heat transfer analysis, with practical supercritical CO2 boundary conditions, was performed on the design with Rene 80 as the metal. The conjugate heat transfer model had a thermal barrier coating which consisted of 0.1 mm of NiCrAlY bond coat and 0.3 mm of YSZ. The investigation consisted of a construction of a relationship between cooling effectiveness and heat load parameter, internal cooling turn losses, external airfoil temperature profiles and a thermal boundary layer analysis at areas of interest. A recommendation for internal turn inlet-apex-outlet area ratios is provided for minimizing the dynamic pressure loss associated with the turn. The study concluded that heat transfer not only depends on buffer zone temperature, but also viscous sublayer thickness.
Harmonic Method for Simulating Unsteady Multispool Interactions
Authors: Wang Feng , di Mare Luca 
Published: October 2022

Abstract
Modern civil jet engines arrange components on spools with different rotational speeds in order to improve compressor stall margin, overall engine performance, etc. The unsteady interactions among these components can be significant and should be considered at an early design stage if possible. URANS is a common approach to simulate these unsteady effects, but the disparity in time scales in a multispool simulation can lead to expensive URANS simulations. Harmonic methods are effective and efficient approaches to simulate unsteady interactions among turbomachinery components, but their applications to multispool simulations remains a challenge. The objective of this paper is to address this challenge. This paper extends the Favre-averaged non-linear harmonic method to simulate multispool turbomachinery components using a unified bladerow interface which transfer disturbances with arbitrary blade counts at any rotational speed. The regularization of non-reflective boundary condition is described for certain circumferential wave number of the zero-frequency mode. The capability of the proposed approach is demonstrated by simulating the transfer of hot streaks through full 3D high- and intermediate-pressure turbines in a three-shaft engine. The temperature distributions from the harmonic method show good agreement with direct unsteady simulation and the radial migration of the hot streaks towards the hub are captured very well by the proposed harmonic method. The Favre-averaged temperature field also shows good agreement with direct unsteady simulation. The required computational cost of the harmonic method can be roughly two orders of magnitude smaller than the direct unsteady simulations. This demonstrates the proposed method can be a promising design tool to trace hot streaks in multispool turbines at the early design stage.
Comparison of Stall Point Predictions in a Transonic Axial Compressor Rotor Using Single Passage and Three Passage CFD Geometries
Authors: Meinster Benjamin , Smith Walter C. , Hobson Garth V. , Gannon Anthony J. 
Published: October 2022

Abstract
An investigation is presented which compares the predicted stall points and underlying flow fields for single-passage and three-passage CFD geometries of a transonic axial compressor rotor. The two cases are run using the commercial CFD code ANSYS CFX and compared to experimental data. The two predicted stall points are found to differ from each other, and both under-predict the rotor’s performance compared to the experimental data. However, the steady-state flow fields are found to be identical for all operating points short of the stall point. A mechanism is then proposed to reconcile the difference in predicted stall points with the identical steady-state flow fields. By the mechanism proposed, the addition of multiple passages makes flow through the three-blade geometry less stable, which causes the rotor to stall earlier.
Evaluation of Pressure Gain and Turbine Inlet Conditions in a Pulse Combustion Gas Turbine
Authors: Sakurai Takashi , Sekiguchi Takehiro , Inoue Sora 
Published: October 2022

Abstract
This study investigates the pressure gain and its improvement on the gas turbine performance. The combustor is comprised from two combustion chambers. One chamber A conducts pulse combustion and the other chamber B conducts continuous, constant-pressure combustion. The burned gases of each chamber are mixed and enter the turbine. The detail time variation of chamber pressure as well as turbine inlet and compressor outlet under the pulse combustion mode were experimentally investigated. The pulse combustion in the chamber A generated the pressure wave that propagated not only downstream to the turbine inlet but also chamber upstream. This pressure wave stagnated the gas flow from the compressor in the chamber A. The gas flow velocities at the chamber inlet and outlet of chamber A were measured. The results showed the large velocity variation in one cycle under the pulse combustion mode. Based on the velocity, the cycle-averaged pressures in the chamber A were evaluated by mass-averaging method. The estimated cycle-averaged pressure ratio became 1.067 means that a pressure gain of 6.7% was obtained in the chamber A. Although the hydrogen fuel mass flow rate in the pulse combustion mode was larger than that in the normal combustion mode, the apparent higher value of specific output power in the pulse combustion mode than in the normal combustion mode demonstrated the feature of pressure-gain combustion.
The STEP 10 MWe sCO2 Pilot Demonstration Status Update
Authors: Marion John , Macadam Scott , McClung Aaron , Mortzheim Jason 
Published: October 2022

Abstract
The Gas Technology Institute (GTI®), Southwest Research Institute® (SwRI®) and General Electric Global Research (GE-GR) are executing the Supercritical Transformational Electric Power, “STEP” project, to design, construct, commission, and operate an integrated and reconfigurable 10 MWe sCO2 [supercritical CO2] Pilot Plant Test Facility. The $156* million project is funded $115 million by the US DOE’s National Energy Technology Laboratory (NETL Award Number DE-FE0028979) and $41* million by the team members, component suppliers, and Joint Industry Program (JIP) members. The facility is currently under final assembly and is located at SwRI’s San Antonio, Texas, USA campus. This project is a significant step toward sCO2 cycle based power generation commercialization and is informing the performance, operability, and scale-up to commercial plants.
Significant progress has been made on this STEP project. The design phase is complete (Phase 1) and included procurements of long-lead time delivery components. Now well into Phase 2, a ground-breaking was held in 2018, and civil work and the construction of a dedicated 22,000 ft2 building was completed in 2020. Most major equipment is in final fabrication or delivered to site as of the end of 2021. These efforts have already provided valuable project learnings for technology commercialization. At time of paper writing most equipment has been received and installed, and commissioning will begin in the first half of 2022. An update on commissioning and experience with sCO2 equipment is given here-in.
Exploring Determinants of Exercise-Related Affective Valence in Regular Exercisers Between the Ages of 55 and 69 Years
Authors: Smith-Ricketts Jessica , Beaumont Cory T. , Fleming Jessica K. , Hornbuckle Lyndsey M. , Strohacker Kelley 
Published: October 2022

This study aimed to understand determinants of recalled in-task affective valence experienced during a regularly performed aerobic bout in adult exercisers aged 55+. Qualitative data were collected (January to March, 2021, during the COVID-19 pandemic) using interviews wherein individuals (N = 16, 69% women, 61 ± 5 years) recalled deviations in affective valence in response to a regularly completed bout. Using thematic analyses, two themes emerged regarding how COVID-19 impacted regular exercise behaviors: (a) “loss” and (b) “adaptation.” Two themes encompassed the determinants of recalled in-task affective valence: (a) “person-specific conditions” and (b) “external conditions.” Finally, an increase in duration/intensity during a pleasant session was indicated by 44% of the participants, while 75% indicated a decrease in duration/intensity during an unpleasant session. The participants indicated that affective valence was determined by previously cited and novel factors that relate to exercise performed in naturalistic environments. Volitional modifications to planned exercise volume appear more responsive to feelings of displeasure.
A curious case of metastatic parotid adenoid cystic carcinoma to kidney
Authors: Ho Ning Xuan , O’Meara Sorcha , Moran Tom , McGuire Barry 
Published: October 2022

A woman in her 60s presented with a 2-week history of non-specific left-sided abdominal pain. She previously underwent a total parotidectomy and adjuvant radiotherapy for left parotid adenoid cystic carcinoma 13 years prior, with a local recurrence 4 years after. Investigations revealed a large left-sided renal mass with appearances of renal carcinoma and no signs of metastatic disease. Pathology following nephrectomy revealed a metastatic adenoid cystic carcinoma.Metastatic disease recurred 11 months postradical nephrectomy to the contralateral kidney and lung, and she was referred to medical oncology for further management.This case history demonstrates the highly aggressive nature of an adenoid cystic carcinoma primary of salivary gland origin with rare metastasis to the kidney.
Comparative analysis of all-terrain vehicles, motorcycle and automobile-related trauma in a rural border community of the USA
Authors: Elzaim Haissam S , Vatcheva Kristina , Torres-Reveron Annelyn , Pequeno Gregery , Betancourt-Garcia Monica M 
Published: October 2022

IntroductionThere is widespread use of all-terrain vehicles (ATVs) in the USA for both work-related and recreational activities. In this study, we aimed to determine the difference in injury severity, Glasgow Coma scales and length of stay between ATV-related injuries and injuries sustained from motorcycles (MOTOs) and automobiles (AUTOs).MethodsWe retrospectively analysed ATV, MOTO and AUTO injuries from a Level 2 Trauma Center between 01 January 2015 and 31 August 2020. Proportional odds regression analyses, as well as multivariable regression models, were used to analyse the data.ResultsThere were significantly more male and paediatric patients that suffered ATV-related injuries compared with MOTO or AUTO injuries. Victims of ATV-related injuries were also more likely to have open fractures. Paediatric patients were less likely to sustain an injury from either AUTO or MOTO accidents compared with ATV accidents. Patients with no drug use during injury and those who used protective equipment such as seat belts and child seats were significantly associated with lower Injury Severity Scores and higher Glasgow Coma Scale scores, indicating less severe injuries.DiscussionPaediatric patients are very likely to suffer sequela and long-term disability due to the severity of ATV-related injuries. Public awareness campaigns to educate our population, especially our youth, about the danger of ATV use are highly needed.