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SAE International 2019 AeroTech Europe conference, AEROTECHEUR 2019

作者： Teixeira, Odelma Pascoa, Jose Universidade da Beira Interior Portugal

This work aims to expand the applicability of an open-source numerical tool to solve hypersonic gas dynamic flows for space propulsion geometries. This is done by validating the code using two well-known hypersonic test cases, the double cone and the hollow cylinder flare, used by the NATO Research and Technology Organization for the validation of hypersonic flight for laminar viscous-inviscid interactions (D. Knight, "RTO WG 10 - Test cases for CFD validation of hypersonic flight," in 40th aiaa Aerospace Sciences Meeting & exhibit, 2002). The Computational Fluid Dynamic (CFD) simulation is conducted using the two-temperature solver hy2Foam that is capable to study external aerodynamics in re-entry flows. In the present work the assessment of hy2Foam to solve hypersonic complex flow features with strong interactions including non-equilibrium effects was demonstrated. Freestream conditions with stagnation enthalpy of 5.44 MJ/kg and Mach number of 12.2, for the double cone case, and stagnation enthalpy of 5.07 MJ/kg and Mach number of 11.3 for the hollow cylinder case were considered. Comparison with newer existing numerical data and experimental data from LENS XX (Large Energy National Shock Expansion Tunnel Version 2) was also performed. Special attention was taken to the phenomenon of vibrational excitation of the molecules. Different vibrational non-equilibrium models were used and compared with the available data. Hy2Foam showed consistent results, with the vibrational non-equilibrium models reducing the discrepancies between numerical and experimental results. © 2019 SAE International. All Rights Reserved.

关键词： Mach number

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Reynolds-Stress Budgets in an Impinging Shock-Wave/Boundary-Layer Interaction

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aiaa JOURNAL 2019年第11期57卷 4698-4714页

作者： Vyas, Manan A. Yoder, Dennis A. Gaitonde, Datta, V NASA Glenn Res Ctr Inlets & Nozzles Branch 21000 Brookpk RdMS 5-12 Cleveland OH 44135 USA Ohio State Univ Dept Mech & Aerosp Engn Columbus OH 43210 USA

Wall-resolved large-eddy simulations of an impinging shock-wave/boundary-layer interaction (SBLI) are performed to investigate the evolution of Reynolds stresses. After an assessment of accuracy by comparison with experimental data, mechanisms in the Reynolds-stress transport equation, including production, diffusion, strain, and dissipation are examined. In the upstream boundary layer, these quantities are validated with high confidence against published results from the literature. Concerning the SBLI region, all Reynolds stresses exhibit significant growth, consistent with the enhancement of turbulence in adverse pressure gradients. Of particular note is the pressure strain term, which plays a key role in energy redistribution from rho u '' u '' over bar to rho v '' v '' over bar and rho w '' w '' over bar . The pressure diffusion term, commonly assumed to be negligible or combined with turbulent diffusion in Reynolds-stress models, becomes larger than the production and pressure strain terms in the region where the impinging shock crosses the shear layer above the separation bubble. Power spectra of u ' in this region show links to shear layer flapping and Kelvin-Helmholtz-type instability. In the vicinity of the growth in pressure diffusion, turbulent mass flux also exhibits amplification. Critically, in the rho u '' v '' over bar budget, pressure diffusion and turbulent mass flux behavior for y+>10 suggests that there may be a benefit in considering the terms individually in modeling efforts.

关键词： Boundary Layer Interaction Shock Waves Reynolds Averaged Navier Stokes Direct Numerical simulation Mass Flux Power Spectral Density Normal Stress Flow Conditions Reynolds Stress Turbulence Models Turbulence Models

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Propulsion system simulation using the toolbox for the modeling and analysis of thermodynamic systems (T-MATS) 50

Propulsion system simulation using the toolbox for the model...

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50th aiaa/ASME/SAE/ASEE Joint Propulsion conference and exhibit 2014

作者： Chapman, Jeffryes W. Lavelle, Thomas M. May, Ryan D. Litt, Jonathan S. Guo, Ten-Huei Vantage Partners LLC 3000 Aerospace Parkway Brook ParkOH44142 United States National Aeronautics and Space Administration Glenn Research Center 21000 Brookpark Rd. MS 86-1 ClevelandOH44135 United States National Aeronautics and Space Administration Glenn Research Center 21000 Brookpark Rd. MS 77-1 ClevelandOH44135 United States

ISBN: (数字)9781624103032

ISBN: (纸本)9781624103032

A simulation toolbox has been developed for the creation of both steady-state and dynamic thermodynamic software models. This paper describes the Toolbox for the modeling and Analysis of Thermodynamic Systems (T-MATS), which combines generic thermodynamic and controls modeling libraries with a numerical iterative solver to create a framework for the development of thermodynamic system simulations, such as gas turbine engines. The objective of this paper is to present an overview of T-MATS, the theory used in the creation of the module sets, and a possible propulsion simulation architecture. A model comparison was conducted by matching steady-state performance results from a T-MATS developed gas turbine simulation to a well-documented steady-state simulation. Transient modeling capabilities are then demonstrated when the steady-state T-MATS model is updated to run dynamically. © 2014 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

关键词： Gas turbines

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A process for the creation of T-MATS propulsion system models from NPSS data 50

A process for the creation of T-MATS propulsion system model...

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50th aiaa/ASME/SAE/ASEE Joint Propulsion conference and exhibit 2014

作者： Chapman, Jeffryes W. Lavelle, Thomas M. Litt, Jonathan S. Guo, Ten-Huei Vantage Partners LLC 21000 Brookpark Rd Brook ParkOH44142 United States NASA Glenn Research Center 21000 Brookpark Rd. MS 86-1 ClevelandOH44135 United States NASA Glenn Research Center 21000 Brookpark Rd. MS – 77-1 ClevelandOH44135 United States

ISBN: (数字)9781624103032

ISBN: (纸本)9781624103032

A modular thermodynamic simulation package called the Toolbox for the modeling and Analysis of Thermodynamic Systems (T-MATS) has been developed for the creation of dynamic simulations. The T-MATS software is designed as a plug-in for Simulink® and allows a developer to create system simulations of thermodynamic plants (such as gas turbines) and controllers in a single tool. Creation of such simulations can be accomplished by matching data from actual systems, or by matching data from steady state models and inserting appropriate dynamics, such as the rotor and actuator dynamics for an aircraft engine. This paper summarizes the process for creating T-MATS turbo-machinery simulations using data and input files obtained from a steady state model created in the Numerical Propulsion System simulation (NPSS). The NPSS is a thermodynamic simulation environment that is commonly used for steady state gas turbine performance analysis. Completion of all the steps involved in the process results in a good match between T-MATS and NPSS at several steady state operating points. Additionally, the T-MATS model extended to run dynamically provides the possibility of simulating and evaluating closed loop responses. © 2014 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

关键词： Gas turbines

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50th aiaa/ASME/SAE/ASEE Joint Propulsion conference, 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 2014

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50th aiaa/ASME/SAE/ASEE Joint Propulsion conference and exhibit 2014

ISBN: (纸本)9781624103032

The proceedings contain 527 papers. The special focus in this conference is on Identifying and Highlighting how Innovative Aerospace Propulsion technologies Powering Both New and Evolving Systems. The topics include: Analysis of hypersonic flow using three dimensional navier-stokes equations;theoretical investigation and modeling of current extraction from a radio-frequency cathode;pulsed plasma thrusters for atmospheric operation;modelling and optimization of electrode-less helicon plasma thruster with different propellants;integrated design tools for RF antennas for helicon plasma thrusters;plasma source optimization for multispecies helicon plasma thruster;study about ablative coated carbon materials applied on chambers of LRE;effect of novel alternative fuels and compositions on vibrations of a gas turbine engine;measurement of film thickness in gas-centered swirl coaxial injectors;impulse vector characteristics of a laser-driven vehicle;flow characterization of high velocity oxy-fuel thermal sprays;results from the RIT-22 technology maturity demonstration activity;neutralizer-free gridded ion thruster;development and test of the negative and positive ion thruster PEGASES;design and preliminary testing plan of electronegative ion thruster;numerical simulation of the cathode plume of a hall thruster;numerical momentum tracking for a hall thruster plume;experimental investigation of breakup of annular liquid sheet in a hybrid atomizer;combustion dynamics behavior in a single-element lean direct injection (LDI) gas turbine combustor;a second generation swirl-venturi lean direct injection combustion concept and flow field and liner heat transfer for a model annular combustor equipped with radial swirlers.

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modeling the deterioration of engine and low pressure compressor performance during a roll back event due to ice accretion 50

Modeling the deterioration of engine and low pressure compre...

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50th aiaa/ASME/SAE/ASEE Joint Propulsion conference and exhibit 2014

作者： Jorgenson, Philip C. E. Veres, Joseph P. Jones, Scott M. Turbomachinery and Heat Transfer Branch NASA Glenn Research Center 21000 Brookpark Rd /Mail Stop 5-11 ClevelandOH44135 United States Engine Icing Technical Challenge Turbomachinery and Heat Transfer Branch NASA Glenn Research Center 21000 Brookpark Rd /Mail Stop 5-11 ClevelandOH44135 United States Aerospace Engineer Multidisciplinary Design Analysis and Optimization Branch NASA Glenn Research Center 21000 Brookpark Rd /Mail Stop 5-11 ClevelandOH44135 United States

ISBN: (数字)9781624103032

ISBN: (纸本)9781624103032

The main focus of this study is to apply a computational tool for the flow analysis of the engine that has been tested with ice crystal ingestion in the Propulsion Systems Laboratory (PSL) of NASA Glenn Research Center. A data point was selected for analysis during which the engine experienced a full roll back event due to the ice accretion on the blades and flow path of the low pressure compressor. The computational tool consists of the Numerical Propulsion System simulation (NPSS) engine system thermodynamic cycle code, and an Euler-based compressor flow analysis code, that has an ice particle melt estimation code with the capability of determining the rate of sublimation, melting, and evaporation through the compressor blade rows. Decreasing the performance characteristics of the low pressure compressor (LPC) within the NPSS cycle analysis resulted in matching the overall engine performance parameters measured during testing at data points in short time intervals through the progression of the roll back event. Detailed analysis of the fan-core and LPC with the compressor flow analysis code simulated the effects of ice accretion by increasing the aerodynamic blockage and pressure losses through the low pressure compressor until achieving a match with the NPSS cycle analysis results, at each scan. With the additional blockages and losses in the LPC, the compressor flow analysis code results were able to numerically reproduce the performance that was determined by the NPSS cycle analysis, which was in agreement with the PSL engine test data. The compressor flow analysis indicated that the blockage due to ice accretion in the LPC exit guide vane stators caused the exit guide vane (EGV) to be nearly choked, significantly reducing the air flow rate into the core. This caused the LPC to eventually be in stall due to increasing levels of diffusion in the rotors and high incidence angles in the inlet guide vane (IGV) and EGV stators. The flow analysis indicating compresso

关键词： Stators

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Pitch Motion Perception Thresholds During Passive and Active Tasks

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2012年第3期35卷 904-918页

作者： Pais, A. R. Valente Pool, D. M. de Vroome, A. M. Van Paassen, M. M. Mulder, M. Delft Univ Technol Fac Aerosp Engn Control & Simulat Div NL-2600 GB Delft Netherlands

Knowledge about motion perception thresholds is essential for simulator motion cueing. Thresholds are generally measured in a passive experimental setup in which subjects do not actively influence their motion. For flight simulation applications, it is useful to also investigate thresholds during control tasks, where pilots actively influence the motion they sense. In this paper, thresholds were estimated during an active control task using a pilot model parameter identification method. A comparison with conventional passive threshold measurements was made. The threshold identification method was based on a multichannel pilot model extended with a nonlinear absolute threshold element. Two experiments were performed in a flight simulator: a passive experiment to measure the sensory pitch threshold, and an active experiment with a compensatory control task to identify the active pitch threshold. In the active experiment, the gain of the inertial motion amplitude was varied and two types of compensatory control tasks were considered. For both tasks, the pitch threshold was identifiable only for high motion gain levels. The measured passive threshold was lower than other values found in literature. The threshold identified from the active control task was higher than the measured passive threshold, but it was comparable with passive threshold values reported in other studies.

关键词： Pilot modeling Linear Time Invariant Flight simulation Pilot Roll Control Pilot Control IMU Angular Motion Analysis of Variance Genetic Algorithm

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Aircraft system study of boundary layer ingesting propulsion 48

Aircraft system study of boundary layer ingesting propulsion

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48th aiaa/ASME/SAE/ASEE Joint Propulsion conference and exhibit 2012

作者： Hardin, Larry W. Tillman, Gregory Sharma, Om P. Berton, Jeffrey Arend, David J. United Technologies Research Center 411 Silver Ln East Hartford CT 06108 United States NASA Glenn Research Center 21000 Brookpark Rd Cleveland OH 44135 United States

ISBN: (数字)9781600869358

ISBN: (纸本)9781600869358

A trade-factor-based system study has been carried out to identify fuel burn benefits associated with boundary layer ingestion (BLI) for generation-after-next (N+2) aircraft and propulsion system concepts. The analysis includes detailed propulsion system engine cycle modeling for a next-generation, Ultra-High-Bypass (UHB) propulsion system with BLI using the Numerical Propulsion System simulation (NPSS) computational model. Cycle modeling was supplemented with one-dimensional theory to identify limiting theoretical BLI benefits associated with the blended wing body reference vehicle used in the study. The system study employed low-order models of engine extractions associated with inlet flow control;nacelle weight and drag;fan performance;and inlet pressure losses. Aircraft trade factors were used to estimate block fuel burn reduction for a long-range commercial transport mission. Results of the study showed that a 3-5% BLI fuel burn benefit can be achieved for N+2 aircraft relative to a baseline high-performance, pylon-mounted, UHB propulsion system. High-performance, distortion-tolerant turbomachinery, and low-loss, low-drag inlet systems, were identified as key enabling technologies. Larger benefits were estimated for N+3 configurations for which larger fractions of aircraft boundary layer can be ingested. © 2012 by United technologies Research Center.

关键词： Fuels

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Model-based verification and validation of spacecraft avionics

Model-based verification and validation of spacecraft avioni...

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aiaa Infotech at Aerospace conference and exhibit 2012

作者： Omair Khan, M. Sievers, Michael Standley, Shaun System Verification and Validation Group Jet Propulsion Laboratory California Institute of Technology MS179-260 Pasadena CA 91109-8099 United States Computer Systems and Technologies Group Jet Propulsion Laboratory California Institute of Technology MS156-142 Pasadena CA 91109-8099 United States

ISBN: (纸本)9781600869396

Verification and Validation (V&V) at JPL is traditionally performed on flight or flightlike hardware running flight software. For some time, the complexity of avionics has increased exponentially while the time allocated for system integration and associated V&V testing has remained fixed. There is an increasing need to perform comprehensive system level V&V using modeling and simulation, and to use scarce hardware testing time to validate models;the norm for thermal and structural V&V for some time. Our approach extends model-based V&V to electronics and software through functional and structural models implemented in SysML. We develop component models of electronics and software that are validated by comparison with test results from actual equipment. The models are then simulated enabling a more complete set of test cases than possible on flight hardware. SysML simulations provide access and control of internal nodes that may not be available in physical systems. This is particularly helpful in testing fault protection behaviors when injecting faults is either not possible or potentially damaging to the hardware. We can also model both hardware and software behaviors in SysML, which allows us to simulate hardware and software interactions. With an integrated model and simulation capability we can evaluate the hardware and software interactions and identify problems sooner. The primary missing piece is validating SysML model correctness against hardware;this experiment demonstrated such an approach is possible. © 2012 by the American Institute of Aeronautics and Astronautics, Inc.

关键词： Access control

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Aircraft Control System Validation via Hardware-in-the Loop simulation

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JOURNAL OF AIRCRAFT 2011年第4期48卷 1466-1468页

作者： Waszniowski, Libor Hanzalek, Zdenek Doubrava, Jiri Czech Tech Univ Fac Elect Engn Ctr Appl Cybernet Dept Control Engn Prague 12135 2 Czech Republic AERO Vodochody As Dept Aircraft Syst Dev Odolena Voda 25070 Czech Republic

The article discusses the validation of the yaw damper controller (YDC) with hydraulic actuators, an aircraft control system, using the hardware-in-the-loop (HIL) simulation. It describes the YDC and the HIL simulator, along with practical experiences that show the usefulness of the HIL simulation in detecting errors in the system components. The relevance of the dynamics of the actuators, force sensor and actuator nonlinearities and control law to YDC validation are explained.

关键词： AIR traffic control EQUIPMENT & supplies ACTUATORS AIRPLANE control systems ERROR analysis (Mathematics) AIRPORTS -- Communication systems

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