bluuebunny/crossref_metadata_2025_split huggingface dataset:
Industrial Wastewater As an Enabler of Green Ammonia to Power via Gas Turbine Technology
Authors: Hewlett S. G. , Pugh D. G. , Valera-Medina A. , Giles A. , Runyon J. , Goktepe B. , Bowen P. J. 
Published: January 2021

Abstract
This experimental study follows on from detailed Chemkin-Pro numerical analyses assessing the viability of by-product ammonia (NH3) utilization for power generation in gas turbines (GTs). This study looks specifically at NH3 in the industrial wastewaters of steelworks, resulting from the cleansing of coke oven gas (COG). The by-product NH3 is present in an aqueous blend of 60–70%vol water and is normally destroyed.
An experimental campaign was conducted using a premixed swirl burner in a model GT combustor, previously employed in the successful combustion of NH3/hydrogen blends, with favorable NOx and unburned fuel emissions. This study experimentally investigates the combustion performance of combining anhydrous and aqueous by-product NH3 in an approximate 50:50%vol blend, comparing the performance with that of each ammonia source unblended. Green anhydrous NH3, a rapidly growing research topic, is a carbon-free energy vector for renewable hydrogen. Some potential benefits of combining the two sources are suggested.
Ammonia combustion presents two major challenges, poor reactivity and a potential for excessive NOx emissions. Prior numerical analyses predicted that 15%vol addition of steelworks COG, at an inlet temperature of 550 K, may provide sufficient support for raising the reactivity of the NH3-based fuels, whilst limiting undesirable emissions. Therefore, addition of 10, 15 and 20%vol COG to each NH3-based fuel was investigated experimentally at 25 kW power with inlet temperatures &gt; 500 K, at atmospheric pressure.
As nitric oxide (NO) emissions decrease significantly with increasing fuel-to-air ratio, experiments were conducted at equivalence ratios (Φ) between 1.0 and 1.3, the precise range of Φ for each blend being optimized according to the modeling predictions for emissions. Leading blends, anhydrous NH3 with 15%vol COG and the 50:50%vol blend with 15%vol COG, achieved &lt; 100 ppm and &lt; 200 ppm NO respectively.
Modest-sized steel plants produce ∼10 metric tons of by-product NH3/day. Aspen Plus was used to model a Brayton-Rankine cycle with integrated recuperation. Adopting typical losses (48% cycle efficiency) and ∼1.2 MPa combustor inlet pressure, the net electrical power generation of 15%vol COG blended with 10 tonnes/day of aqueous industrial NH3 and 25 tonnes/day of anhydrous NH3 (i.e. achieving a 50:50%vol blend) was ∼4.7 MW, ∼47% more power than for the same amount of anhydrous NH3 with 15%vol COG. This significant increase, indicates how industrial NH3 could enable green NH3 to power.
Investigation of Similarity Criteria for an Internally-Cooled Turbine Vane Based on Artificial Neural Networks: Part I — Comparison of Similarity Criteria
Authors: Zhao Weicheng , Chi Zhongran , Zang Shusheng 
Published: January 2021

Abstract
This study explores the suitable criterion for the temperature and pressure modeling to measure the overall cooling effectiveness and the reason leading to modeling deviation at relatively low temperature and pressure test condition (Part II), taking the internally-cooled Mark II vane as an example. The method used in this study includes Artificial Neural Network (ANN), Conjugate Heat Transfer (CHT) Computational Fluid Dynamics (CFD) and experiments (Part II).
The average overall cooling effectiveness of the vane was selected as the target modeling parameter. After comparing the modeling error, the results show that matched-Biot number criterion has the best performance at both constant coolant temperature and temperature ratio conditions. The maximum modeling error is 6.4% and 1.2% for those two conditions, respectively.
Furthermore, the performance of these similarity criteria based on empirical correlations without the ANN model were also investigated, which is more feasible in engineering use. The accuracy of matched-Biot number criterion has an obvious decrease in this condition, but it is still the best selection at constant coolant temperature conditions. While the mass flow ratio criterion becomes the most accurate one at constant temperature ratio conditions.
A High-Speed Disk Rotor Rig Design for Tip Aerothermal Research
Authors: Lu S. , Zhang Q. , He L. 
Published: January 2021

Abstract
The relative casing motion can greatly vary the Over-Tip-Leakage (OTL) flow structure and thermal performance. The existing tip experimental research facilities include stationary linear cascade, cascade rigs with low speed moving belt, or high-speed rotor rigs are either not capable of reproducing the high relative casing Mach number, or extremely expensive and still difficult for optical measurement. This paper presents a highspeed disk rotor design which can simulate the high casing relative speed. The unique feature of this rig design concept is that it enables full optical access of the tip surface under the engine-representative OTL flow condition. In this paper, the feasibility of the design concept is demonstrated and assessed by RANS CFD simulation, both in component level and whole rig system level. The design idea demonstrated in this paper can be useful for a wide range of tip leakage flow studies.
Modeling Complex Contact Conditions and Their Effect on Blade Dynamics
Authors: Gastaldi Chiara , Gross Johann , Scheel Maren , Berruti Teresa M. , Krack Malte 
Published: January 2021

Abstract
Dry friction devices such as underplatform dampers are commonly included in turbine bladed disks designs to mitigate structural vibrations and avoid high cycle fatigue failures. The design of frictionally damped bladed disks requires adequate models to represent the friction contact. A widely used approach connects contact node pairs with normal and tangential springs and a Coulomb friction law. This simple model architecture is effective in capturing the softening behavior typically observed on frictionally damped structures subjected to increasing forcing levels.
An unexpected hardening behavior was observed on the frequency response functions of two-blades-plus-damper system tested by the authors in a controlled laboratory environment. The reason behind this unexpected behavior will be carefully analyzed and linked to the damper kinematics and to the dependence of contact elasticity on the contact pressure. The inadequacy of contact models with constant spring values will be discussed and alternatives will be proposed. The importance of being able to represent complex contact conditions in order to effectively predict the system dynamics is shown here using a laboratory demonstrator, however its implications are relevant to any other case where large contact pressure variations are to be expected. The nonlinear steady state simulations of the blades-plus-damper system will be carried out using an in-house code exploiting the Multi-Harmonic Balance Method (MHBM) in combination with the Alternating Frequency Time (AFT) Method.
Gas Turbine Performance Digital Twin for Real-Time Embedded Systems
Authors: Panov V. , Cruz-Manzo S. 
Published: January 2021

Abstract
This contribution reports on the development of Performance Digital Twin for industrial Small Gas Turbines. The objective of this study was the development of automation systems with control and monitoring functionalities, capable of addressing the requirements of future gas turbine plants for increased availability and reliability by use of Digital Twin technology.
The project explored development of Performance Digital Twin based on Real-Time Embedded computing, which can be leveraged with Internet-of-Things (IOT) Cloud Platforms. The proposed solution was provided in a form of modular software for a range of hardware platforms, with corresponding functionalities to support advanced control, monitoring, tracking and diagnostics strategies.
The developed Digital Twin was designed to be used in offline mode to assist the software commissioning process and in on-line mode to enable early detection of degradation and fault modes typical for gas path components. The Performance Digital Twin is based on a dynamic gas turbine model which was augmented with a Kalman tuner to enable performance tracking of physical assets.
To support heterogeneity of gas turbine Distributed Control Systems (DCS), this project explored deployment of Digital Twin on multiple platforms. In the paper, we discuss model-based design techniques and tools specific for continuous, discrete and hybrid systems.
The hybrid solution was deployed on PC-based platform and integrated with engine Distributed Control System in the field. Monitoring of gas turbine Performance Digital Twin functionalities has been established via Remote Monitoring System (STA-RMS). Assessment of deployed solution has been carried out and we present results from the field trial in this paper.
The discrete solution was deployed on a range of Programable Logical Controller (PLC) platforms and has been tested by integrating Digital Twin in virtual engine Distributed Control System network. The Performance Digital Twin was embedded in Single Master PLC and Master-Slave PLC configurations, and we present results from the system testing using virtual gas turbine assets. The IoT Platform MindSphere was integrated within virtual engine network, and in this contribution, we explore expansion of the developed system with Cloud based applications and services.
A Numerical Study on Conjugate Heat Transfer for Supercritical CO2 Turbine Blade With Cooling Channels
Authors: Khadse Akshay , Curbelo Andres , Vesely Ladislav , Kapat Jayanta S. 
Published: January 2021

Abstract
The first stage of turbine in a Brayton cycle faces the maximum temperature in the cycle. This maximum temperature may exceed creep temperature limit or even melting temperature of the blade material. Therefore, it becomes an absolute necessity to implement blade cooling to prevent them from structural damage. Turbine inlet temperatures for oxy-combustion supercritical CO2 (sCO2) are promised to reach blade material limit in near future foreseeing need of turbine blade cooling. Properties of sCO2 and the cycle parameters can make Reynolds number external to blade and external heat transfer coefficient to be significantly higher than those typically experience in regular gas turbines. This necessitates evaluation and rethinking of the internal cooling techniques to be adopted.
The purpose of this paper is to investigate conjugate heat transfer effects within a first stage vane cascade of a sCO2 turbine. This study can help understand cooling requirements which include mass flow rate of leakage coolant sCO2 and geometry of cooling channels. Estimations can also be made if the cooling channels alone are enough for blade cooling or there is need for more cooling techniques such as film cooling, impingement cooling and trailing edge cooling. The conjugate heat transfer and aerodynamic analysis of a turbine cascade is carried out using STAR CCM+. The turbine inlet temperature of 1350K and 1775 K is considered for the study considering future potential needs. Thermo-physical properties of this mixture are given as input to the code in form of tables using REFPROP database. The blade material considered is Inconel 718.
Reliability Analysis on Fatigue Life of Turbine Disk Regarding for the Correlation Between Divided Zones
Authors: Chen Gaoxiang , Fan Jiang 
Published: January 2021

Abstract
Failure of a turbine disk may occur in multiple parts of the disk. It should be taken into consideration that during the process of failure, the failure risk of other relevant parts tend to increase due to the change of stress state of the disk. Therefore, the failure risks of different parts are related. This paper puts forward a reliability analysis method considering the failure correlation between different zones of the disk. Firstly, the dependence between the low cycle fatigue (LCF) of the whole turbine disk and the LCF of each zone is considered in building a multivariate reliability model based on Copula function theory. With utilizing the sample points obtained by finite element method (FEA), the multidimensional maximum likelihood theory is used to estimate the parameters in the marginal distribution of turbine disk life and the correlation coefficients in the Copula model, and to quantify the failure correlation between each zone of the turbine disk. With regard to the lifetime output of different zones, fourth-order polynomial high-precision surrogate models are established, which greatly improves the efficiency of Monte Carlo simulation. Eventually, the LCF life reliability analysis of GH720Li turbine disk is performed.
An Investigation of Fundamental Combustion Properties of the Oxygenated Fuels DME and OME1
Authors: Ngugi John M. , Richter Sandra , Braun-Unkhoff Marina , Naumann Clemens , Riedel Uwe 
Published: January 2021

Abstract
Demands of energy will increase worldwide. The use of alternative and renewable energy resources is an attractive option to counteract climate change connected with the burning of fossil fuels. Moreover, improvements in fuel flexibility are a pre-requisite to meet the challenge of a sustainable production of energy in the near future. Within this context, oxygenated molecules, in particular ethers are of high interest because they can be produced renewably. In addition, ethers are promising considerably reduced emissions of particles and soot. In future, ethers might play a role as an alternative fuel (blend) for power generation in gas turbines and in the transport sector.
Dimethylether (DME: CH3OCH3) and oxymethylenether (OMEn: CH3O(CH2O)nCH3) are regarded as some of the most promising alternatives to fossil fuels, in particular in compression ignition engines.
In this work, we report on a combined experimental and modeling study: The oxidation of mixtures of dimethylether as well as of the simplest oxymethylenether (OME1) was investigated. The focus was put on two fundamental combustion properties: (i) ignition delay times measured in a shock tube device, at ambient and elevated pressures up to 16 bar, for stoichiometric mixtures, and (ii) laminar flame speed data, at ambient and elevated pressures up to 6 bar, determined for OME1. The experimental data base was used for the validation of several detailed chemical-kinetic reaction mechanisms taken from literature. Sensitivity analysis was performed for the two selected targets to allow a better insight into the oxidation network within the envisaged wide parameter range.
The findings of the present work will contribute to a better understanding of the combustion of these specific ethers, and to the design and optimization of burners and engines as well.
Modeling the Transport of Fuel Mixture Perturbations and Entropy Waves in the Linearized Framework
Authors: Kaiser Thomas Ludwig , Oberleithner Kilian 
Published: January 2021

Abstract
In this paper a new method is introduced to model the transport of entropy waves and equivalence ratio fluctuations in turbulent flows. The model is based on the Navier-Stokes equations and includes a transport equation for a passive scalar, which may stand for entropy or equivalence ratio fluctuations. The equations are linearized around the mean turbulent fields, which serve as the input to the model in addition to a turbulent eddy viscosity, which accounts for turbulent diffusion of the perturbations. Based on these inputs, the framework is able to predict the linear response of the flow velocity and passive scalar to harmonic perturbations that are imposed at the boundaries of the computational domain. These in this study are fluctuations in the passive scalar and/or velocities at the inlet of a channel flow. The code is first validated against analytic results, showing very good agreement. Then the method is applied to predict the convection, mean flow dispersion and turbulent mixing of passive scalar fluctuations in a turbulent channel flow, which has been studied in previous work with Direct Numerical Simulations (DNS). Results show that our code reproduces the dynamics of coherent passive scalar transport in the DNS with very high accuracy and low numerical costs, when the DNS mean flow and Reynolds stresses are provided. Furthermore, we demonstrate that turbulent mixing has a significant effect on the transport of the passive scalar fluctuations. Finally, we apply the method to explain experimental observations of transport of equivalence ratio fluctuations in the mixing duct of a model burner.
Rapid Characterization of Fatigue Performance With Application to Additive Manufactured Components
Authors: Celli Dino A. , Shen M.-H. Herman , Scott-Emuakpor Onome E. , George Tommy J. 
Published: January 2021

Abstract
The aim of this paper is to provide a fatigue life prediction method which can concurrently approximate both SN behavior as well as the inherent variability of fatigue efficiently with a limited number of experimental tests. The purpose of such a tool is for the quality assessment and verification of components using Additive Manufacturing (AM) processes and other materials with a limited knowledgebase. Interest in AM technology is continually growing in many industries, such as aerospace, automotive, or biomedical. But components often result in highly variable fatigue performance. The determination of optimal process parameters for the build process can be an extensive and costly endeavor due to either a limited knowledgebase or proprietary restrictions. Quantifying the significant variability of fatigue performance in AM components is a challenging task as there are many causes including machine to machine differences, recycles of powder, and process parameter selection. Therefore, a life prediction method which can rapidly determine the fatigue performance of a material with little or no prior information of the material and a limited number of experimental tests is developed as an aid in process parameter selection and fatigue performance qualification. This is performed by using a previously developed and simplistic energy based fatigue life prediction method, or Two Point method, to predict the inherent variability associated with fatigue performance. The proposed approach is verified by using predicted distributions of stress and cycles to failure and comparing with experimental data at 104 and 106 cycles to failure. SN life prediction is modeled via a modified Random Fatigue Limit (RFL) model where the two RFL model parameters are evaluated using Bayesian statistical inference and stochastic sampling techniques for distribution estimation. This is performed in a dynamic way such that the life prediction model is continually updated with the generation of experimental data.
Influence of Splitter Blades on the Performance of a Single-Stage Centrifugal Compressor With Pressure Ratio 12.0
Authors: Zhang Wenchao , Sun Zhenzhong , Wang Baotong , Zheng Xinqian 
Published: January 2021

Abstract
High performance centrifugal compressors with high pressure ratio are highly applied in turboshaft engines in order to obtain higher power-to-weight ratio and lower fuel consumption. The optimization of the aerodynamic configuration design of splitter blades is one of the effective ways to achieve higher efficiency. An in-house designed single-stage centrifugal compressor with a pressure ratio up to 12.0 is studied in this paper. By using a three-dimensional CFD (computational fluid dynamic) method, this paper investigates influences of the number of splitter blades and their leading edge position on the flow field characteristics and aerodynamic performance of the centrifugal compressor with ultra-high pressure ratio. Results show that three critical flow characteristics lead to severe losses in centrifugal compressor impeller when only full blades are applied. Those flow characteristics include the strong shock wave, the severe tip clearance flow at the inlet region and the severe flow separation at the rear region. Therefore, the inlet blade number should be reduced to decrease the loss caused by strong shock waves and tip clearance flow, while the outlet blade number should be sufficient enough to suppress flow separation. By optimizing the number and the leading edge position of splitters, the performance can be improved under the reduction of combined losses caused by shock waves, tip clearance flow and flow separation. When an aerodynamic configuration with single-splitters is used, numerical results indicate that the leading edge position of splitter blades should be located at 60% of the main blade chord length, and the centrifugal impeller isentropic efficiency with ultra-high pressure ratio can be increased from 82.4% (the aerodynamic configuration with only full blades) to 89.5%; when an aerodynamic configuration with double-splitters is used, the leading edge positions of middle and short splitter blades should be respectively located at 40% and 60% of the main blade chord length, and the impeller isentropic efficiency can be further improved to 90.9%.
Real Time Diagnostic Method of Gas Turbines Operating Under Transient Conditions in Hybrid Power Plants
Authors: Tsoutsanis Elias , Hamadache Moussa , Dixon Roger 
Published: January 2021

Abstract
Recent expansion of renewable power plants have transformed the role and operation of gas turbines to a great extent. From the base load operation era we are moving into a flexible and dynamic engine operation of gas turbines. In particular, aero derivative engines that have the capacity to start up, shut down in a short time frame are becoming quite popular for both hybrid power plant arrangements and distributed electricity generation. Advances in computational intelligence, such as digital twins, have amplified the importance of condition monitoring, diagnostics and prognostics capabilities in the face of gas turbine operation. Given the dynamic operating profile of the gas turbines, it is of paramount importance to develop, tune and deploy engine models that are accurate and robust to accommodate their nonlinear behavior. Performing diagnostics in transient conditions has recently gained attention, since the gas turbines are acting as partners of renewables and they have a supporting role. Among a family of diagnostics methods, one that has real time capabilities is based on zero-dimensional engine models. This paper present a novel diagnostic approach for determining the health of a gas turbine when it works in conjunction with a wind farm in hybrid power plant. In contrary to our earlier works, where we have mathematically modeled component maps to derive the health of an engine, in this paper we propose a model-based diagnostic method without reconstructing component maps according to their degradation. Once the engine model is initially adapted to its clean condition, it is subsequently tuned in real time to reflect the changes in both the operation and degradation with respect to a benchmark engine model. Time evolving multiple component degradation scenarios for a gas turbine operating in conjunction with a wind farm, are simulated to test the accuracy and efficiency of the proposed method. From a bank of simulated measurements, data trending is performed which facilitates the detection of degradation and provides useful conclusions about the health state of the engine. This diagnostic method is suitable for gas turbines that spend most of their life time in part-load and transient operation and it forms a simple and useful tool for operators in planning their assets maintenance in a computational efficient and accurate manner.