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Prof. Maria Grazia De Giorgi
Department of Engineering for Innovation, University of Salento, Via Per Arnesano, I-73100 Lecce, Italy

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0 Combustion
0 Energy Systems
0 Fluid machinery
0 Propulsive systems
0 Applied fluid dynamics

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Propulsive systems

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Journal article
Published: 08 August 2021 in Acta Astronautica
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The present work discusses an experimental investigation of the flow into a silicon-based vaporizing liquid microthruster equipped with sensing capabilities and low-power on-channel secondary heaters. The sensing capabilities (resistance temperature detectors and capacitive void fraction sensors) are used to investigate the flow instability and to evaluate its performances. The device has a sandwich structure composed of a silicon substrate and a glass substrate. This last one allows optical access into the device. The main heating of the propellant is provided using a platinum resistive heater placed on the bottom of the silicon layer. By varying the electrical power supplied to the main heater at fixed mass flow rate, three flow regimes have been observed and investigated: fully liquid flow, two-phase flow, and fully vaporized flow. Their dynamics have been captured through high-speed micro-flow visualizations under rough vacuum conditions (about 29 kPa). Furthermore, the expansion of the exhaust vapor plume exiting from the micronozzle has been analyzed via Schlieren visualizations. Results highlighted the occurrence of a cyclic flow behavior during the two-phase flow regime. In contrast, the flow exhibits the presence of both liquid and vapor phases at the micronozzle exit. Once the fully vaporized flow regime is established, the two-phase flow dynamics into the inlet chamber become more stable with complete filling and more uniform distribution of the flow at the microchannels entrance. Schlieren imaging captured the increase of the exhaust plume spreading half-angle when moving from ambient condition towards rough vacuum.

ACS Style

D. Fontanarosa; L. Francioso; M.G. De Giorgi; C. De Pascali; A. Ficarella; M.R. Vetrano. Flow regime characterization of a silicon-based vaporizing liquid microthruster. Acta Astronautica 2021, 1 .

AMA Style

D. Fontanarosa, L. Francioso, M.G. De Giorgi, C. De Pascali, A. Ficarella, M.R. Vetrano. Flow regime characterization of a silicon-based vaporizing liquid microthruster. Acta Astronautica. 2021; ():1.

Chicago/Turabian Style

D. Fontanarosa; L. Francioso; M.G. De Giorgi; C. De Pascali; A. Ficarella; M.R. Vetrano. 2021. "Flow regime characterization of a silicon-based vaporizing liquid microthruster." Acta Astronautica , no. : 1.

Journal article
Published: 29 July 2021 in Aerospace
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One of the most important parts of a turboshaft engine, which has a direct impact on the performance of the engine and, as a result, on the performance of the propulsion system, is the engine fuel control system. The traditional engine control system is a sensor-based control method, which uses measurable parameters to control engine performance. In this context, engine component degradation leads to a change in the relationship between the measurable parameters and the engine performance parameters, and thus an increase of control errors. In this work, a nonlinear model predictive control method for turboshaft direct fuel control is implemented to improve engine response ability also in presence of degraded conditions. The control objective of the proposed model is the prediction of the specific fuel consumption directly instead of the measurable parameters. In this way is possible decentralize controller functions and realize an intelligent engine with the development of a distributed control system. Artificial Neural Networks (ANN) are widely used as data-driven models for modelling of complex systems such as aeroengine performance. In this paper, two Nonlinear Autoregressive Neural Networks have been trained to predict the specific fuel consumption for several transient flight maneuvers. The data used for the ANN predictions have been estimated through the Gas Turbine Simulation Program. In particular the first ANN predicts the state variables based on flight conditions and the second one predicts the performance parameter based on the previous predicted variables. The results show a good approximation of the studied variables also in degraded conditions.

ACS Style

Maria De Giorgi; Luciano Strafella; Antonio Ficarella. Neural Nonlinear Autoregressive Model with Exogenous Input (NARX) for Turboshaft Aeroengine Fuel Control Unit Model. Aerospace 2021, 8, 206 .

AMA Style

Maria De Giorgi, Luciano Strafella, Antonio Ficarella. Neural Nonlinear Autoregressive Model with Exogenous Input (NARX) for Turboshaft Aeroengine Fuel Control Unit Model. Aerospace. 2021; 8 (8):206.

Chicago/Turabian Style

Maria De Giorgi; Luciano Strafella; Antonio Ficarella. 2021. "Neural Nonlinear Autoregressive Model with Exogenous Input (NARX) for Turboshaft Aeroengine Fuel Control Unit Model." Aerospace 8, no. 8: 206.

Journal article
Published: 23 June 2021 in Applied Sciences
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The present work investigates the impact of steady micro-jet blowing on the performance of a planar micro-nozzle designed for both liquid micro-thrusters and nitrogen cold-gas micro-resistojets. Two micro-injectors have been placed into the divergent region along the sidewalls, injecting a secondary flow of propellant perpendicularly to the wall where they have been located. The micro-jet actuator configuration is characterized by the dimensionless momentum coefficient cμ. The best performance improvement is retrieved at the maximum cμ for both water vapor (Δ%T,jet = +22.6% and Δ%Isp,Tjet = +2.9% at cμ = 0.168) and nitrogen gaseous flows (Δ%T,jet = +36.1% and Δ%Isp,Tjet = +9.1% at cμ = 0.297). The fields of the Mach number and the Schlieren computations, in combination with the streamline visualization, reveal the formation of two vortical structures in the proximity of secondary jets, which energize the core flow and enhance the expansion process downstream secondary jets. The compressible momentum thickness along the width-wise direction θxy in presence of secondary injection reduces as a function of cμ. In particular, it becomes smaller than the one computed for the baseline configuration at cμ > 0.1, decreasing up to about and -57% for the water vapor flow at cμ = 0.168, and -64% for the nitrogen gaseous flow at cμ = 0.297.

ACS Style

Donato Fontanarosa; Maria De Giorgi; Antonio Ficarella. Thrust Augmentation of Micro-Resistojets by Steady Micro-Jet Blowing into Planar Micro-Nozzle. Applied Sciences 2021, 11, 5821 .

AMA Style

Donato Fontanarosa, Maria De Giorgi, Antonio Ficarella. Thrust Augmentation of Micro-Resistojets by Steady Micro-Jet Blowing into Planar Micro-Nozzle. Applied Sciences. 2021; 11 (13):5821.

Chicago/Turabian Style

Donato Fontanarosa; Maria De Giorgi; Antonio Ficarella. 2021. "Thrust Augmentation of Micro-Resistojets by Steady Micro-Jet Blowing into Planar Micro-Nozzle." Applied Sciences 11, no. 13: 5821.

Journal article
Published: 18 June 2021 in Aerospace Science and Technology
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The objective of this paper is to investigate the effects of Dielectric Barrier Discharge (DBD) plasma actuators on the aeroelastic control of a subsonic compressor cascade, for unsteady load mitigation and enhancement in the cascade aeroelastic response. Numerical simulations of the blades oscillating in traveling wave mode are performed with the commercial solver Ansys FLUENT®. Results are then validated through comparison with experimental data to assess the stability and convergence of the reference grid. Aeroelastic control is achieved by means of two AC-DBD plasma actuators installed on the trailing edge of the compressor blades, one on the suction side and one on the pressure side. Alleviation of the blade load is realized by operating alternately the actuators through a cosinusoidal function. Moreover, the effect of the actuation force phase on the blade load control is evaluated. Based on the actuation phase, results show that it is possible to manipulate effectively the unsteady lift and moment coefficients, stabilizing the compressor performance, alleviating fatigue phenomena and enlarging the flutter limits of the cascade. Plasma actuators confirm to be a very promising technology for active flow control in turbomachines and aeronautical applications.

ACS Style

Maria Grazia De Giorgi; Valentina Motta; Antonio Suma; Alessia Laforì. Comparison of different plasma actuation strategies for aeroelastic control on a linear compressor cascade. Aerospace Science and Technology 2021, 117, 106902 .

AMA Style

Maria Grazia De Giorgi, Valentina Motta, Antonio Suma, Alessia Laforì. Comparison of different plasma actuation strategies for aeroelastic control on a linear compressor cascade. Aerospace Science and Technology. 2021; 117 ():106902.

Chicago/Turabian Style

Maria Grazia De Giorgi; Valentina Motta; Antonio Suma; Alessia Laforì. 2021. "Comparison of different plasma actuation strategies for aeroelastic control on a linear compressor cascade." Aerospace Science and Technology 117, no. : 106902.

Data article
Published: 29 December 2020 in Data in Brief
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The article presents the data regarding the experimental characterization of combustion of liquid jet A1 with addition of urea-water emulsion. A liquid-fuel gas turbine derived burner operating in non-premixed mode under three different equivalence fuel/air ratios was used. The data were collected, with and without urea addition, with two high speed visualization systems which acquired the broadband and spatially and spectrally resolved chemiluminescence emissions. Chemiluminescence images of OH* were acquired using an intensified camera system with a narrow-band filter at approximately 310 nm CWL, while the chemiluminescence images of CH* were recorded with a 436 nm CWL. Measurements of exhaust temperature and NOx, CO and CO2 emissions have been also performed. The data presented here are related to the article entitled “COMBUSTION PERFORMANCE OF A LOW NOx GAS TURBINE COMBUSTOR USING UREA ADDITION INTO LIQUID FUEL” [1].

ACS Style

Maria Grazia De Giorgi; Giuseppe Ciccarella; Donato Fontanarosa; Elisa Pescini; Antonio Ficarella. Experimental data regarding the effects of urea addition into liquid fuel to combustion enhancement of a low NOx gas turbine combustor. Data in Brief 2020, 34, 106702 .

AMA Style

Maria Grazia De Giorgi, Giuseppe Ciccarella, Donato Fontanarosa, Elisa Pescini, Antonio Ficarella. Experimental data regarding the effects of urea addition into liquid fuel to combustion enhancement of a low NOx gas turbine combustor. Data in Brief. 2020; 34 ():106702.

Chicago/Turabian Style

Maria Grazia De Giorgi; Giuseppe Ciccarella; Donato Fontanarosa; Elisa Pescini; Antonio Ficarella. 2020. "Experimental data regarding the effects of urea addition into liquid fuel to combustion enhancement of a low NOx gas turbine combustor." Data in Brief 34, no. : 106702.

Journal article
Published: 16 December 2020 in Fuel
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The present work provides an experimental investigation on the effects of the urea addition in water emulsified fuels in terms of combustion performance and emissions. Experiments have been carried out using a test rig equipped with a 300-kW Jet-A1 fueled swirling burner operating under lean conditions. Different equivalence ratios and various urea in water percent concentrations have been tested. Measurements of temperature and emissions have been performed, in combination with high-speed flame imaging in visible and ultraviolet spectral ranges. Results have shown that the use of 2.5 wt% (percent concentration by weight) water-2 wt% urea solution into Jet-A1 fuel represents a promising combustion control strategy, since it leads to the same nitrogen oxides (NOx) reduction of a leaner neat fuel flame (about 30% less than the neat fuel case), but without significant penalty on the overall combustion performance, viz. combustion temperature, thermal and combustion efficiencies and pollutant emissions. The snapshot Proper Orthogonal Decomposition (POD) of the broadband flame emission images, methylidyne radical and hydroxyl radical chemiluminescence allowed to characterize of the flame dynamics and the flame stability. Differences between the flame regimes were also investigated by the POD mode 3 eigenstructure. The reduced flame stability for the leaner operating condition was confirmed by the energy increase of the first POD modes. The more unstable flame dynamics was confirmed by the frequency distribution of the phase points in the POD phase-space of modes 1 and 2 that highlighted a significant rise of the phase angles occurrence in the range [−π/6, π/6].

ACS Style

Donato Fontanarosa; Maria Grazia De Giorgi; Giuseppe Ciccarella; Elisa Pescini; Antonio Ficarella. Combustion performance of a low NOx gas turbine combustor using urea addition into liquid fuel. Fuel 2020, 288, 119701 .

AMA Style

Donato Fontanarosa, Maria Grazia De Giorgi, Giuseppe Ciccarella, Elisa Pescini, Antonio Ficarella. Combustion performance of a low NOx gas turbine combustor using urea addition into liquid fuel. Fuel. 2020; 288 ():119701.

Chicago/Turabian Style

Donato Fontanarosa; Maria Grazia De Giorgi; Giuseppe Ciccarella; Elisa Pescini; Antonio Ficarella. 2020. "Combustion performance of a low NOx gas turbine combustor using urea addition into liquid fuel." Fuel 288, no. : 119701.

Journal article
Published: 05 August 2020 in Journal of Fluids Engineering
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A preliminary two-dimensional (2D) numerical investigation of the active control of unsteady cavitation by means of one single synthetic jet actuator (SJA) is presented. The investigation involves the cloud-cavitating flow of water around a NACA 0015 hydrofoil with an angle of attack of 8-deg and ambient conditions. The SJA locates on the suction side at a distance of 16% of the chord from the leading edge; it has been modeled by means of a user-defined velocity boundary conditions based on a sinusoidal waveform. A Eulerian homogeneous mixture model has been used, coupled with an extended Schnerr–Sauer cavitation model and a volume of fluid interface tracking method. As first, a sensitivity analysis allowed to evaluate the influence of the main control parameters, namely, the momentum coefficient Cμ, the dimensionless frequency F+, and the jet angle αjet. As a result, the best performing SJA configuration was retrieved at Cμ=0.0002, F+=0.309, and αjet=90 deg, which led to a reduction of both the average vapor content and the average torsional load in the measure of 34.6% and 17.8%. The analysis of the coupled dynamics between vapor cavity–vorticity and their proper orthogonal decomposition (POD)-based modal structures highlighted the benefit of the SJA lies in preventing the growth of a thick sheet cavity, which causes the development of the highly cavitating cloud dynamics after the cavity breakup. This is mainly due to an additional vorticity close to the hydrofoil surface just downstream the SJA, as well as a local pressure modification close the SJA during the blowing stroke.

ACS Style

Maria Grazia De Giorgi; Donato Fontanarosa; Antonio Ficarella. Active Control of Unsteady Cavitating Flows Over Hydrofoil. Journal of Fluids Engineering 2020, 142, 1 .

AMA Style

Maria Grazia De Giorgi, Donato Fontanarosa, Antonio Ficarella. Active Control of Unsteady Cavitating Flows Over Hydrofoil. Journal of Fluids Engineering. 2020; 142 (11):1.

Chicago/Turabian Style

Maria Grazia De Giorgi; Donato Fontanarosa; Antonio Ficarella. 2020. "Active Control of Unsteady Cavitating Flows Over Hydrofoil." Journal of Fluids Engineering 142, no. 11: 1.

Data article
Published: 04 July 2020 in Data in Brief
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The design of aeroengine real-time control systems needs the implementation of machine learning based techniques. The lack of in-flight aeroengine performance data is a limit for the researchers interested in the development of these prediction algorithms. Dynamic aeroengine models can be used to overcome this lack. This data article presents data regarding the performance of a turbojet that were predicted by the dynamic engine model that was built using the Gas turbine Simulation Program (GSP) software. The data were also used to implement an Artificial Neural Network (ANN) that predicts the in-flight aeroengine performance, such as the Exhaust Gas Temperature (EGT). The Nonlinear AutoRegressive with eXogenous inputs (NARX) neural network was used. The neural network predictions have been also given as dataset of the present article. The data presented here are related to the article entitled “MultiGene Genetic Programming - Artificial Neural Networks approach for dynamic performance prediction of an aeroengine” [1].

ACS Style

Maria Grazia De Giorgi; Marco Quarta. Data regarding dynamic performance predictions of an aeroengine. Data in Brief 2020, 31, 105977 .

AMA Style

Maria Grazia De Giorgi, Marco Quarta. Data regarding dynamic performance predictions of an aeroengine. Data in Brief. 2020; 31 ():105977.

Chicago/Turabian Style

Maria Grazia De Giorgi; Marco Quarta. 2020. "Data regarding dynamic performance predictions of an aeroengine." Data in Brief 31, no. : 105977.

Journal article
Published: 11 June 2020 in Aerospace Science and Technology
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Dynamic aeroengine models have an important role in the design of real-time control systems. Modelling of aeroengines using dynamic performance simulations is a key step in the design process in order to reduce costs and the development period. A dynamic model can provide a numerical counterpart for the development of control systems and for the study of the engine behaviour in both steady and unsteady scenarios. The latter situation is particularly felt in the military field. The Viper 632-43 engine analysed in this work is a military turbojet, so it was necessary to develop a model that would replicate its behaviour as realistically as possible. The model was built using the Gas turbine Simulation Program (GSP) software and validated both in steady and transient conditions. Once the engine model was validated, different machine learning techniques were used to estimate (data mining) and predict an engine parameter; the Exhaust Gas Temperature (EGT) has been chosen as the key parameter. A MultiGene Genetic Programming (MGGP) technique has been used to derive simple mathematical relationships between different input parameters and the EGT. These, then, can be used to calculate the EGT value of a real Viper 632-43 engine knowing a priori the input parameters and in any operating condition. Finally, the EGT estimated by this algorithm has been added to the dataset used for the one-step-ahead EGT prediction by Artificial Neural Network (ANN). A time-series ANN was used for the EGT prediction, i.e. the Nonlinear AutoRegressive with eXogenous inputs (NARX) neural network. This network recognizes the input data as a real time series and is therefore able to predict the output in the next time step. It was chosen to use, as forecasting method, the one-step-ahead technique which allows to predict the EGT in the immediately next time step.

ACS Style

Maria Grazia De Giorgi; Marco Quarta. Hybrid MultiGene Genetic Programming - Artificial neural networks approach for dynamic performance prediction of an aeroengine. Aerospace Science and Technology 2020, 103, 105902 .

AMA Style

Maria Grazia De Giorgi, Marco Quarta. Hybrid MultiGene Genetic Programming - Artificial neural networks approach for dynamic performance prediction of an aeroengine. Aerospace Science and Technology. 2020; 103 ():105902.

Chicago/Turabian Style

Maria Grazia De Giorgi; Marco Quarta. 2020. "Hybrid MultiGene Genetic Programming - Artificial neural networks approach for dynamic performance prediction of an aeroengine." Aerospace Science and Technology 103, no. : 105902.

Journal article
Published: 20 March 2020 in Energies
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The present work focuses on the impact of dielectric barrier discharge (DBD) plasma actuators (PAs) on non-premixed lifted flame stabilization in a methane CH4-air Bunsen burner. Two coaxial DBD-PA configurations are considered. They are composed of a copper corona, installed on the outer surface of a quartz tube and powered with a high voltage sinusoidal signal, and a grounded needle installed along the burner axis. The two configurations differ in the standoff distance value, which indicates the positioning of the high frequency/high voltage (HV) electrode’s upper edge with respect to the needle tip. Experimental results highlight that flame reattachment is obtained at a lower dissipated power when using a negative standoff distance (i.e., placing the needle upstream with respect to the corona). At 11 kV peak-to-peak voltage and 20 kHz frequency, plasma actuation allowed for reattaching the flame with a very low dissipated power (of about 0.05 W). Numerical simulations of the electrostatic field confirmed that this negative standoff configuration has a beneficial effect on the momentum sources, which oppose the flow and show that the highest electric field extends into the inner quartz tube, as confirmed by experimental visualization close to the needle tip. The modeling predicted an increase in the gas temperature of about 21.8 °C and a slight modification of the fuel composition at the burner exit. This impacts the flame speed with a 10% increase close to the stoichiometric conditions with respect to the clean configuration.

ACS Style

Maria Grazia De Giorgi; Antonio Ficarella; Donato Fontanarosa; Elisa Pescini; Antonio Suma. Investigation of the Effects of Plasma Discharges on Methane Decomposition for Combustion Enhancement of a Lean Flame. Energies 2020, 13, 1452 .

AMA Style

Maria Grazia De Giorgi, Antonio Ficarella, Donato Fontanarosa, Elisa Pescini, Antonio Suma. Investigation of the Effects of Plasma Discharges on Methane Decomposition for Combustion Enhancement of a Lean Flame. Energies. 2020; 13 (6):1452.

Chicago/Turabian Style

Maria Grazia De Giorgi; Antonio Ficarella; Donato Fontanarosa; Elisa Pescini; Antonio Suma. 2020. "Investigation of the Effects of Plasma Discharges on Methane Decomposition for Combustion Enhancement of a Lean Flame." Energies 13, no. 6: 1452.

Data article
Published: 13 February 2020 in Data in Brief
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The data regard the analysis reported in the research article “Influence of actuation parameters of multi-DBD plasma actuators on the static and dynamic behavior of an airfoil in unsteady flow” [1]. The data are related to the study focused on the evaluation of the effects of an active flow control system on the performance of an airfoil in an unsteady flow, with particular focus on the influence of actuation parameters on the global performances.

ACS Style

Maria Grazia De Giorgi; Valentina Motta; Antonio Suma. Data regarding the computational fluid dynamics simulations of an airfoil with plasma actuator in unsteady flow. Data in Brief 2020, 29, 105286 .

AMA Style

Maria Grazia De Giorgi, Valentina Motta, Antonio Suma. Data regarding the computational fluid dynamics simulations of an airfoil with plasma actuator in unsteady flow. Data in Brief. 2020; 29 ():105286.

Chicago/Turabian Style

Maria Grazia De Giorgi; Valentina Motta; Antonio Suma. 2020. "Data regarding the computational fluid dynamics simulations of an airfoil with plasma actuator in unsteady flow." Data in Brief 29, no. : 105286.

Journal article
Published: 29 January 2020 in Journal of Engineering for Gas Turbines and Power
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This work aimed to investigate cavitating flows of water, liquid hydrogen, and nitrogen on hydrofoils numerically, using the open source code openfoam. The Eulerian homogeneous mixture approach has been used, consisting in a mass transfer model, which is based on the combination of a two-phase incompressible unsteady solver with a volume of fluid interface tracking method. Thermal effects have been introduced by means of the activation of energy equation and latent heat source terms plus convective heat source term. The dependency of the saturation conditions to the temperature has been defined using Antoine-like equations. An extended Schnerr–Sauer model based on the classical nucleation theory (CNT) has been implemented for the computation of the interfacial mass transfer rates. In order to investigate the nucleation effects, an extension of the CNT has been considered by coupling the population balance equation (PBE)/extended quadrature-based method of moments with the computational fluid dynamics (CFD) model, which has been defined in combination with a transport equation for the nuclei density. Results showed that nucleation determined a nonuniform field of nuclei density so as to produce a reduction of the temperature drop inside the vapor bubbles, as well as a warmed wake downstream the vapor cavity. Unsteady computations also revealed an influence of the nucleation on the dynamics of the vapor cavity and the bubble detachment.

ACS Style

Maria Grazia De Giorgi; Antonio Ficarella; Donato Fontanarosa. Numerical Investigation of Nonisothermal Cavitating Flows on Hydrofoils by Means of an Extended Schnerr–Sauer Model Coupled With a Nucleation Model. Journal of Engineering for Gas Turbines and Power 2020, 142, 1 .

AMA Style

Maria Grazia De Giorgi, Antonio Ficarella, Donato Fontanarosa. Numerical Investigation of Nonisothermal Cavitating Flows on Hydrofoils by Means of an Extended Schnerr–Sauer Model Coupled With a Nucleation Model. Journal of Engineering for Gas Turbines and Power. 2020; 142 (4):1.

Chicago/Turabian Style

Maria Grazia De Giorgi; Antonio Ficarella; Donato Fontanarosa. 2020. "Numerical Investigation of Nonisothermal Cavitating Flows on Hydrofoils by Means of an Extended Schnerr–Sauer Model Coupled With a Nucleation Model." Journal of Engineering for Gas Turbines and Power 142, no. 4: 1.

Editorial
Published: 27 December 2019 in Applied Sciences
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Active flow control (AFC) is a fast-growing, multi-disciplinary science and technology for energy and propulsive systems

ACS Style

Maria Grazia De Giorgi; Antonio Ficarella. Special Issue “Active Flow Control Technologies for Energy and Propulsive Systems”. Applied Sciences 2019, 10, 221 .

AMA Style

Maria Grazia De Giorgi, Antonio Ficarella. Special Issue “Active Flow Control Technologies for Energy and Propulsive Systems”. Applied Sciences. 2019; 10 (1):221.

Chicago/Turabian Style

Maria Grazia De Giorgi; Antonio Ficarella. 2019. "Special Issue “Active Flow Control Technologies for Energy and Propulsive Systems”." Applied Sciences 10, no. 1: 221.

Conference paper
Published: 17 December 2019 in MATEC Web of Conferences
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Dynamic aeroengine model plays a key role in the design of engine control systems. Moreover, modelling of the engine using performance simulations is an important step in the design process in order to reduce costs, decrease risks and shortening development period. Parameters such as engine spool speeds, vibration, oil temperature, exhaust gas temperature, and fuel flow are often used to estimate performance in gas turbine engines. In this study, two artificial neural network methods were used for the prediction, under transient operations, of one of the most important engine parameters, the Exhaust Gas Temperature (EGT). The data used for model training are time series datasets of several different flight missions, which have been created using a gas path analysis, and that allow to simulate the engine transient behaviour. The study faces the challenge of setting up a robust and reliable Nonlinear Input-Output (NIO) and a Nonlinear AutoRegressive with eXog nous inputs (NARX) models, by means of a good selection of training. At the end of the study, two network that predicts the engine EGT in transient operations with the smallest error have been identified.

ACS Style

Maria Grazia De Giorgi; Antonio Ficarella; Marco Quarta. Dynamic performance simulation and control of an aeroengine by using NARX models. MATEC Web of Conferences 2019, 304, 03005 .

AMA Style

Maria Grazia De Giorgi, Antonio Ficarella, Marco Quarta. Dynamic performance simulation and control of an aeroengine by using NARX models. MATEC Web of Conferences. 2019; 304 ():03005.

Chicago/Turabian Style

Maria Grazia De Giorgi; Antonio Ficarella; Marco Quarta. 2019. "Dynamic performance simulation and control of an aeroengine by using NARX models." MATEC Web of Conferences 304, no. : 03005.

Conference paper
Published: 17 December 2019 in MATEC Web of Conferences
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The present work provides a numerical investigation of the supersonic flow inside a planar micronozzle configuration under different gas rarefaction conditions. Two different propellants have been considered, namely water vapor and nitrogen, which relate to their use in VLMs (the former) and cold gas microthrusters (the latter), respectively. Furthermore, two different numerical approaches have been used due to the different gas rarefaction regime, i.e. the typical continuum Navier–Stokes with partial slip assumption at walls and the particle–based Direct Simulation Monte Carlo (DSMC) technique. As a result, under high–pressure operating conditions, both water and nitrogen flows supersonically expanded into the micronozzle without chocking in combination with a linear growth of the boundary layer on walls. However, when low–pressure operating condition are imposed and a molecular regime is established inside the micronozzle, a very rapid expansion occurred close to the nozzle exit in combination with a strong chocking of the flow and a micronozzle quality reduction of about 40%. Furthermore, water exhibited specific higher specific impulse than nitrogen above 60%.

ACS Style

Maria Grazia De Giorgi; Donato Fontanarosa; Antonio Ficarella. Comparison of numerical predictions of the supersonic expansion inside micronozzles of micro–resistojets. MATEC Web of Conferences 2019, 304, 02012 .

AMA Style

Maria Grazia De Giorgi, Donato Fontanarosa, Antonio Ficarella. Comparison of numerical predictions of the supersonic expansion inside micronozzles of micro–resistojets. MATEC Web of Conferences. 2019; 304 ():02012.

Chicago/Turabian Style

Maria Grazia De Giorgi; Donato Fontanarosa; Antonio Ficarella. 2019. "Comparison of numerical predictions of the supersonic expansion inside micronozzles of micro–resistojets." MATEC Web of Conferences 304, no. : 02012.

Conference paper
Published: 17 December 2019 in MATEC Web of Conferences
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The aim of this study is to investigate the performance of dielectric barrier discharge plasma actuators (DBD-PAs) applied to control the aeroelastic response of a compressor cascade in subsonic flow conditions. Simulations involve a cascade composed by 7-blade, 3 of which show a not-synchronous pitching behaviour. Two different inter blade phase angle (IBPA) have been tested and compared. Actuators capabilities in terms of load alleviation and instability control have been evaluated through the measurement of mean value, standard deviation and hysteresis area of the airfoil response in terms of lift and moment coefficients.

ACS Style

Maria Grazia De Giorgi; Antonio Suma; Alessia Laforì; Antonio Ficarella. Dielectric Barrier Discharge Plasma Actuator for Load Alleviation and Instability Control in a Compressor Cascade. MATEC Web of Conferences 2019, 304, 01006 .

AMA Style

Maria Grazia De Giorgi, Antonio Suma, Alessia Laforì, Antonio Ficarella. Dielectric Barrier Discharge Plasma Actuator for Load Alleviation and Instability Control in a Compressor Cascade. MATEC Web of Conferences. 2019; 304 ():01006.

Chicago/Turabian Style

Maria Grazia De Giorgi; Antonio Suma; Alessia Laforì; Antonio Ficarella. 2019. "Dielectric Barrier Discharge Plasma Actuator for Load Alleviation and Instability Control in a Compressor Cascade." MATEC Web of Conferences 304, no. : 01006.

Conference paper
Published: 17 December 2019 in SECOND INTERNATIONAL CONFERENCE ON MATERIAL SCIENCE, SMART STRUCTURES AND APPLICATIONS: ICMSS-2019
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Due to the stringent emission requirements for a more sustainable transport, the efforts of the scientific community have gone into research and development of eco-friendly fuels for aeroengines. Water emulsified fuels represents a promising solution. In this regard, the present work provides two main contributions. First, an experimental investigation of the effects of the addition of water into jet-A1 fuel has been carried out on a 300-kW liquid-fueled swirling combustor. Direct measurements of both exhaust temperature and pollutant emissions, defined the diagnostics setup. Several water concentrations have been tested at different fuel/air ratios and under lean conditions, and the impact of each fuel composition has been evaluated on emissions reduction and combustor efficiency. Results pointed out the nitrogen oxides (NOx) reduction in combination with the lowering of the exhaust gas temperature, which coupled with losses in the combustion and in the overall thermal efficiencies. Despite this, the energy losses became negligible when water content in Jet-A1 was limited to 2.5% by mass, which still ensured the benefit in terms of NOx reduction in the measure of about 11% at Φ = 0.36 up to 27.4% at Φ = 0.18. Further increase of the water content to 5% at fixed Φ = 0.36, as well as going to a leaner condition (Φ = 0.18) at fixed water content of 2.5%, strongly impacted on the thermal efficiency which reduced to about 25.4% and 41.2%, respectively. Based on the thermal efficiency losses estimated through experimental results, a gas path analysis was performed by implementing a gas turbine model. This allowed to predict the impact of the water addition into Jet-A1 on the performance of the military turbojet Rolls-Royce VIPER 632-43. Both sea level take-off and cruise flight conditions have been analyzed. Numerical predictions confirmed the experimental finding of the NOx reduction in proportion to the reduction of the peak combustion temperature. In addition, the turbojet engine model figured out an increase of the thrust specific fuel consumption (TSFC) of about 6.7% and 22% for 2.5% and 5% of water in Jet-A1 respectively during sea level take-off. Its value rose to 8.0% and 26.7%, respectively, when under cruise conditions. Water addition decreased the engine thrust in proportion to the percent increment of the TSFC.

ACS Style

Maria Grazia De Giorgi; Giuseppe Ciccarella; Antonio Ficarella; Donato Fontanarosa; Elisa Pescini. Effect of jet-A1 emulsified fuel on aero-engine performance and emissions. SECOND INTERNATIONAL CONFERENCE ON MATERIAL SCIENCE, SMART STRUCTURES AND APPLICATIONS: ICMSS-2019 2019, 2191, 020058 .

AMA Style

Maria Grazia De Giorgi, Giuseppe Ciccarella, Antonio Ficarella, Donato Fontanarosa, Elisa Pescini. Effect of jet-A1 emulsified fuel on aero-engine performance and emissions. SECOND INTERNATIONAL CONFERENCE ON MATERIAL SCIENCE, SMART STRUCTURES AND APPLICATIONS: ICMSS-2019. 2019; 2191 (1):020058.

Chicago/Turabian Style

Maria Grazia De Giorgi; Giuseppe Ciccarella; Antonio Ficarella; Donato Fontanarosa; Elisa Pescini. 2019. "Effect of jet-A1 emulsified fuel on aero-engine performance and emissions." SECOND INTERNATIONAL CONFERENCE ON MATERIAL SCIENCE, SMART STRUCTURES AND APPLICATIONS: ICMSS-2019 2191, no. 1: 020058.

Journal article
Published: 12 December 2019 in Applied Energy
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The present work provides an experimental investigation of the use of water emulsified fuels to control the combustion performance and reduce nitrogen oxides emissions into a Jet-A1 fueled gas turbine combustor. Experiments have been carried out using a test rig equipped with a 300-kW liquid-fueled swirling burner. Several fuel-to-air ratios have been tested in combination with various water concentrations. Measurements of exhaust emissions have been performed. Furthermore, high-speed cameras in visible and ultraviolet spectral ranges, have been used. The snapshot Proper Orthogonal Decomposition of the flame images of both broadband emission and hydroxyl radical chemiluminescence has allowed to detect the most relevant flame structures, in combination with the modal frequency spectra. Results figured out that, the addition of water in the fuels led to lower combustion temperature and consequently to lower thermal nitrogen oxides than the case of neat fuel. On the other hand, the thermal efficiency significantly dropped in presence of high-water content (5% H2O) and ultra-lean conditions, while it remained acceptable at 2.5% H2O and fuel rich conditions. Furthermore, under the near-lean blowout condition, the flame becomes very unstable and flame oscillations take place in the axial direction. This combines with the increase in the relative energy of the first Proper Orthogonal Decomposition modes. Finally, the phase space analysis of modes 1–2 of the hydroxyl radical chemiluminescence emission defined a criterion for the detection of the establishment of the flame instability, which corresponds to phase angles ranging between -π/6 and π/6.

ACS Style

Maria Grazia De Giorgi; Donato Fontanarosa; Antonio Ficarella; Elisa Pescini. Effects on performance, combustion and pollutants of water emulsified fuel in an aeroengine combustor. Applied Energy 2019, 260, 114263 .

AMA Style

Maria Grazia De Giorgi, Donato Fontanarosa, Antonio Ficarella, Elisa Pescini. Effects on performance, combustion and pollutants of water emulsified fuel in an aeroengine combustor. Applied Energy. 2019; 260 ():114263.

Chicago/Turabian Style

Maria Grazia De Giorgi; Donato Fontanarosa; Antonio Ficarella; Elisa Pescini. 2019. "Effects on performance, combustion and pollutants of water emulsified fuel in an aeroengine combustor." Applied Energy 260, no. : 114263.

Journal article
Published: 28 November 2019 in Aerospace Science and Technology
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The purpose of this paper is to perform a numerical study regarding the implementation of dielectric barrier discharge plasma micro-actuators for load alleviation on a NACA 23012 oscillating blade in a freestream flow. The work aims to evaluate the feasibility of using multiple dielectric barrier discharge (multi-DBD PAs) plasma actuators as a novel approach for load alleviation and stability control of airfoils in unsteady flow. A 6-actuators configuration, positioned at the trailing edge, is designed and tested. In this configuration, half of the actuators operate on the suction surface and the others on the pressure surface. In particular, the actuators located on the suction surface reduce the airfoil lift force if the induced body force is in a direction that is opposite of the main flow, because they lead to a slight and local increment of pressure on the surface. Instead, when actuators produce a body force aligned with the streamwise direction, they lead to a slight reduction of pressure, increasing lift. Contrarily, the actuators located on the pressure surface increase the lift, if the induced body force is in the direction opposite of the flow and reduce the lift in the opposite case. The effects of plasma actuators on the flow are incorporated into Navier–Stokes equations as a body force vector into the momentum equation. Different switching on/off laws of the actuators have been are compared, in order to reduce the loads amplitude of the airfoil, and to increase the stability of the blade response to the flow, and thus, alleviating fatigue phenomena on the blade and enhancing its aeroelastic stability. The effect of the phase of the plasma actuators switching law was evaluated for different pitching oscillation reduced frequencies, ranging from 0.1 to 0.5. The results underline the capability of DBD-PAs to control and reduce unsteady loads on an oscillating airfoil, improving also the airfoil stability if the phase of the actuation force is optimized for each pitching oscillation reduced frequency.

ACS Style

Maria Grazia De Giorgi; Valentina Motta; Antonio Suma. Influence of actuation parameters of multi-DBD plasma actuators on the static and dynamic behaviour of an airfoil in unsteady flow. Aerospace Science and Technology 2019, 96, 105587 .

AMA Style

Maria Grazia De Giorgi, Valentina Motta, Antonio Suma. Influence of actuation parameters of multi-DBD plasma actuators on the static and dynamic behaviour of an airfoil in unsteady flow. Aerospace Science and Technology. 2019; 96 ():105587.

Chicago/Turabian Style

Maria Grazia De Giorgi; Valentina Motta; Antonio Suma. 2019. "Influence of actuation parameters of multi-DBD plasma actuators on the static and dynamic behaviour of an airfoil in unsteady flow." Aerospace Science and Technology 96, no. : 105587.

Journal article
Published: 24 September 2019 in Journal of Engineering for Gas Turbines and Power
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The aim of this work is the experimental investigation of the effects of the addition of water and urea into jet fuels, on the reduction of nitrogen oxides (NOx) emissions and eventually improvement of the lean flame stability in aeroengine combustors. Experiments have been carried out using a 300-kW liquid-fueled swirling combustor. Various urea and/or water concentrations have been tested at the same fuel/air ratio. In order to study the flame behavior, noninvasive optical diagnostic techniques, as charge-coupled device (CCD) cameras in different spectral ranges (visible and UV ranges, with different optical filters), have been adopted to analyze the shape and the brightness of the flame structure. Measurements of exhaust emissions (NOx, SO2, carbon monoxide (CO), CO2, and O2) have also been performed in order to evaluate the impact of emulsification on the entire combustion process. Finally, the thermal efficiency losses with respect to the neat jet test case were also analyzed for each emulsified fuel condition.

ACS Style

Maria Grazia De Giorgi; Elisa Pescini; Stefano Campilongo; Giuseppe Ciccarella; Donato Fontanarosa; Antonio Ficarella. Effects of Emulsified Fuel on the Performance and Emission Characteristics of Aeroengine Combustors. Journal of Engineering for Gas Turbines and Power 2019, 141, 1 .

AMA Style

Maria Grazia De Giorgi, Elisa Pescini, Stefano Campilongo, Giuseppe Ciccarella, Donato Fontanarosa, Antonio Ficarella. Effects of Emulsified Fuel on the Performance and Emission Characteristics of Aeroengine Combustors. Journal of Engineering for Gas Turbines and Power. 2019; 141 (10):1.

Chicago/Turabian Style

Maria Grazia De Giorgi; Elisa Pescini; Stefano Campilongo; Giuseppe Ciccarella; Donato Fontanarosa; Antonio Ficarella. 2019. "Effects of Emulsified Fuel on the Performance and Emission Characteristics of Aeroengine Combustors." Journal of Engineering for Gas Turbines and Power 141, no. 10: 1.