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会议名称:

AIAA/SAE/ASEE joint propulsion conference AIAA propulsion and energy forum

召开年:

2015

召开地:

Orlando, FL Orlando, FL

会议文集:

51st AIAA/SAE/ASEE joint propulsion conference 2015: 51st AIAA/SAE/ASEE joint propulsion conference 2015, held at the AIAA propulsion and energy forum 2015, 27-29 July 2015, Orlando, Florida, USA

主办单位:

American Institute of Aeronautics and Astronautics American Institute of Aeronautics and Astronautics

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  • 题名 作者 来源 发表时间 操作
  • Performance Modeling and Optimization Assessment of Variable Pitch Fan for Ultrafan Engine

    作者:Xinyu Yang;Hailong Tang;Min Chen; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    In the pursuit of ever more fuel-efficient aircraft, commercial turbofan engines are trending towards ever higher bypass ratio. However, the progression encounters great challenges in fan stability margin and nacelle weight and drag. As an elegant solution, the variable pitch fan helps maintain the stability margin while enabling the application of a short slimline nacelle. These advantages make the variable pitch fan technology be an attractive option for future ultrahigh bypass ratio turbofan engines. To get a comprehensive understanding of the potential benefits of the variable pitch fan, this paper presents a one-dimensional model of variable pitch fan for quick steady-state performance estimation. Based on the performance model, the preliminary characteristics analysis of variable pitch fan at typical working conditions is performed. Results show notable variation in airflow and engine thrust can be achieved by changing fan pitch meanwhile maintaining a constant fan rotational speed. The thrust adjustment capacity of variable pitch fan can be used to realize thrust reduction during throttling. This paper puts forward a combined throttling method. In comparison with conventional fan rotational speed-down method, the new throttling approach has a 1.5%-2% improvement in cruise SFC.

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  • Performance Modeling and Optimization Assessment of Variable Pitch Fan for Ultrafan Engine

    Xinyu Yang;Hailong Tang;Min Chen;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Power Plant Pre-Design Exploration for a Turbo-Electric Propulsive Fuselage Concept

    作者:Julian Bijewitz;Arne Seitz;Mirko Hornung; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    With intent to advance the exploration of a promising concept for synergistic wake filling propulsion system integration, the power plant characteristics associated with a Propulsive Fuselage Concept are investigated in this paper. In the targeted configuration a turbo electric power train is envisioned comprising an electrically driven, boundary layer ingesting fuselage propulsor in conjunction with two underwing podded Geared Turbofan engines providing electrical power offtake. Addressing the extraction of significant levels of power offtakes, upon the discussion of the modelling approach and simulation setup, a variety of parametric studies are presented with emphasis placed on discussing the operational space available for variations of power offtake as well as the effects on the design characteristics. In addition, exploratory studies on the design and performance characteristics of the fuselage propulsor are presented.

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  • Power Plant Pre-Design Exploration for a Turbo-Electric Propulsive Fuselage Concept

    Julian Bijewitz;Arne Seitz;Mirko Hornung;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • UAH Propulsion Research Center Rocket Test Upgrade

    作者:Daniel A. Jones;Vivian R. Braswell;David M. Lineberry;Robert A. Frederick; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    The University of Alabama in Huntsville's Propulsion Research Center has upgraded major systems at its rocket test facility: a new thrust stand, new propellant feed system, an upgraded data acquisition system, and an altitude simulation chamber. The new thrust stand was designed to withstand 10,000 lbf loading and has a more efficient and reliable calibration system. A new data acquisition chassis was installed on the test stand, the new chassis has 16 high frequency measurement channels, 48 pressure channels, 32 thermocouple channels, 8 strain gauge channels, 48 digital input/output channels, integrated test camera support, analog and digital control cards, and enables remote monitoring of valve states and system pressures. The pressure system was upgraded to support supply pressures of 3,000 psi, and two bulk nitrogen tanks for system pressure were acquired and added to the system. The new tanks provide 110 ft3 of storage volume that can be pressurized up to 3,000 psi. A new high flow oxidizer leg was added to the test cell. The new leg has 1-inch feed lines that allow for up to four times the mass flow rates of the existing system and with the increased supply pressure can offer significantly longer test durations. An altitude simulation system was designed and fabricated for use in the facility. The altitude simulation chamber is a direct connect vacuum chamber that will connect directly to the aft end of a rocket chamber, and is pumped down by four air ejectors capable of reducing the exit pressure to 0.1 psi. Demonstration tests were conducted to prove the enhanced capabilities. The demonstration tests consisted of a 1,600 lbf thrust AeroTech M6000 solid rocket motor, and a 2.7 lb/s LN2 flow test using the new high flow system. Both systems used the augmented data acquisition system for measurements during testing.

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  • UAH Propulsion Research Center Rocket Test Upgrade

    Daniel A. Jones;Vivian R. Braswell;David M. Lineberry;Robert A. Frederick;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Considerations for Safety in University-based Test Operations at the UAH Propulsion Research Center

    作者:Robert A. Frederick; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    Keeping students and university researchers engaged in advancing propulsion technologies through research and education is important for advancing technology and workforce development. Keeping those people safe is important for everyone. The purpose of this paper is to outline seven safety considerations that we have utilized at the Propulsion Research Center (PRC) at the University of Alabama in Huntsville (UAH) to carry out university research projects. The overall objective of our practices is to ensure that no one gets hurt and nothing "expensive" gets broken. Considerations include our university safety resources, a facility usage policy, a safety plan, a test facility site plan, past incident reports, formal training and inspections, external reviews, and personal responsibility. The discussion shows how our perspective on safety has changed from the time we were a just few people performing simple experiments in 1991, to an organization involving over one-hundred people with about 20 to 30 of them engaged in activities that require special safety considerations.

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  • Considerations for Safety in University-based Test Operations at the UAH Propulsion Research Center

    Robert A. Frederick;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • An Overview of the VASIMR® Engine

    作者:Franklin R. Chang;Diaz Jared P. Squire;Mark D. Carter;Aidan M. H. Corrigan;Lawrence Dean;Joseph Farrias;Matthew Giambusso;Greg McCaskill;Tiffany Yao; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    The Variable Specific Impulse Magnetoplasma Rocket (VASIMR®) engine addresses an important need in sustainable space exploration and commercialization; namely, high power electric propulsion. The technology is scalable over the full range of high power applications: from solar-electric propulsion (SEP) robotic missions to fast human interplanetary nuclear-electric propulsion (NEP) missions. The latter are essential to reduce the interplanetary transit time and the associated radiation threat and physiological deconditioning of human crews. This talk will describe the origins and physics foundations of this propulsion system and cover the technical milestones achieved over more than three decades of development, from its early origins in the 1980s at MIT, through its formative years as a NASA project, to its technological maturation at Ad Astra Rocket Company. The talk will also address the historical convergence of key technologies that make the engine viable as a compact, high power in-space propulsion system, including advanced materials, high temperature superconductors and high power solid-state RF technology. We shall discuss the present status of the engine development at Ad Astra, major challenges ahead and the company's current plans for full commercial deployment, first in support of the near-Earth and cislunar space market and later as primary propulsion, enabling robust human deep space exploration.

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  • An Overview of the VASIMR® Engine

    Franklin R. Chang;Diaz Jared P. Squire;Mark D. Carter;Aidan M. H. Corrigan;Lawrence Dean;Joseph Farrias;Matthew Giambusso;Greg McCaskill;Tiffany Yao;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Update on the Nested Hall Thruster Subsystem for the NextSTEP XR-100 Program

    作者:Benjamin A. Jorns;Alec D. Gallimore;Scott J. Hall;Peter Y. Peterson;James E. Gilland;Dan M. Goebel;Richard R. Hofer;Ioannis Mikellides; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    Under the NextSTEP program led by Aerojet Rocketdyne in collaboration with NASA Glenn Research Center, the University of Michigan, and the Jet Propulsion Laboratory, the XR-100 100 kW Electric Propulsion system is being developed to Technology Readiness Level 5. As part of this program, the X3, a Nested Hall Thruster designed to operate at powers up to 200 kW, is being further developed through parallel modeling and experimental efforts with the ultimate goal of supporting a 100 kW-100 hr system test in the final year of the NextSTEP program. Recent developments for the X3 subsystem are presented including a summary of testing and modeling results and design updates in anticipation of a risk reduction test scheduled for the summer of 2018.

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  • Update on the Nested Hall Thruster Subsystem for the NextSTEP XR-100 Program

    Benjamin A. Jorns;Alec D. Gallimore;Scott J. Hall;Peter Y. Peterson;James E. Gilland;Dan M. Goebel;Richard R. Hofer;Ioannis Mikellides;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Development & Qualification Status of the PPS®5000 Hall Thruster Unit

    作者:Olivier Duchemin;Julien Rabin;Lahib Balika;Mathieu Diome;Vincent Guyon;Daniel Vuglec;Xavier Cavelan;Vaitua Leroi; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    The 5-kW PPS®5000 Hall thruster is currently under qualification at Safran, and the life test is now proceeding with about 3,400 hrs cumulated as of end of June 2018, for a total delivered impulse close to 3.1 MN.s. In parallel to the ongoing qualification tests on the primary qualification unit, additional test campaigns are being conducted with other qualification-standard hardware. These parallel activities are in support of the qualification as risk-mitigation actions, or as system-compatibility verifications. This paper reviews the PPS®5000 general design and the overall development and qualification logic. A more detailed discussion focuses on the on-going test activities in support of the PPS®5000 qualification, and the paper concludes with a description of the organization for flight-hardware production ramp-up initiated in parallel.

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  • Development & Qualification Status of the PPS®5000 Hall Thruster Unit

    Olivier Duchemin;Julien Rabin;Lahib Balika;Mathieu Diome;Vincent Guyon;Daniel Vuglec;Xavier Cavelan;Vaitua Leroi;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Iodine Hall-Effect Electric Propulsion System Research, Development, and System Durability Demonstration

    作者:Gabriel F. Benavides;Hani Kamhawi;Jonathan A. Mackey;Thomas W. Haag;Gustavo C. C. Costa; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    This paper reviews recent iodine electric propulsion research and development activities at the NASA Glenn Research Center (GRC). Activities included (ⅰ) investigation of the iodine compatibility of Ba0-Ca0-Al_2O_3 impregnated tungsten hollow cathodes based on a flight heritage design, (ⅱ) investigation of the iodine compatibility of a handful of materials common to propulsion systems, spacecraft, and ground test facilities, (ⅲ) development of reliable iodine feed system technologies, (ⅳ) implementation of test facility improvements in an attempt to mitigate iodine associated negative impacts, and culminated in (ⅴ) an 1,174-hour hybrid iodine-xenon propulsion system durability demonstration (iodine fed Hall-effect thruster with xenon fed cathode). Each of the activities resulted in extensive insights that shall inform future iodine electric propulsion developments. While reliable operation of a BaO-CaO-Al_2O_3 impregnated tungsten hollow cathode on iodine vapor was not achieved, long-term operation on xenon gas in proximity to an iodine fed thruster was demonstrated without any measurable degradation or cross-contamination of the cathode. Furthermore, iodine material corrosion investigations conducted at 300°C over 5, 15, and 30 days showed significant deterioration of all materials evaluated, although the same materials with a silicon coating proved nearly impervious to iodine so long as the coating was not mechanically damaged. Finally, the 1,174-hour durability test demonstration showed that (ⅰ) iodine feed system technologies developed at GRC delivered well-regulated uninterrupted propellant, (ⅱ) implementation of appropriate facility improvements and procedures can limit negative impacts of iodine on test hardware and ground support equipment, although facility challenges with iodine are extensive, and (ⅲ) a Hall-effect thruster operates with similar performance whether employing iodine or xenon propellant over long durations. The work was motivated by strong government and commercial interest in the growing capabilities of small-spacecraft (<500 kg), in combination with interest for denser low-power, high delta-v in-space propulsion systems. This work adds to a growing body of research and development efforts aimed at addressing the many anticipated challenges of implementing iodine as an in-space propellant. This work was conducted under the Advanced In-Space Propulsion (AISP) project funded through the Game Changing Development (GCD) program within NASA's Science Technology Mission Directorate (STMD).

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  • Iodine Hall-Effect Electric Propulsion System Research, Development, and System Durability Demonstration

    Gabriel F. Benavides;Hani Kamhawi;Jonathan A. Mackey;Thomas W. Haag;Gustavo C. C. Costa;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Effect of Density Inhomogeneity in Azimuth on Discharge Oscillation Suppression and Electron Diffusion in Hall Thrusters

    作者:Junhwi Bak;Rei Kawashima;Kimiya Komurasaki;Hiroyuki Koizumi; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    Azimuthal non-uniform propellant supply operation shows representative characteristics of suppressed discharge oscillation and increased axial electron current. These characteristics implicate that, with non-uniform operation, physics underlying oscillation and electron trans-port in Hall thrusters may be able to be studied in a spatiotemporally less strict experimental setup. From this insight, we investigated azimuthal plasma properties of non-uniform propellant operation and its influences on discharge oscillation and electron cross-field transport. The image analysis result reveals non-linear plasma structures elongated in direction of electron azimuthal E × B drift, showing the structure is governed by electrons. From probe measurements, inhomogeneous electron temperature distribution in azimuth direction is observed, and corresponding azimuthal inharmonic ionization is thought to partially contributes to the suppressed discharge oscillation. Also, macroscopic zeroth order azimuthal distribution of plasma potential and electron density shows the distribution is self-consistently generated in a way to enhance electron cross-field drift towards the anode. We estimated amount of current carried by equilibrium zeroth order distribution, which accounts for about 20% of total increased electron current in the non-uniform operation. The physical similarities of the macroscopic transport to microscopic instability induced electron transport are also compared.

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  • Effect of Density Inhomogeneity in Azimuth on Discharge Oscillation Suppression and Electron Diffusion in Hall Thrusters

    Junhwi Bak;Rei Kawashima;Kimiya Komurasaki;Hiroyuki Koizumi;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • A 5,000-hr Heaterless Hollow Cathode Endurance Test

    作者:Dan R. Lev;Gal Alon;Leonid Appel; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    Rafael Heaterless Hollow Cathode (RHHC) is a low current hollow cathode designated for operation with low power Hall and ion thrusters. The cathode has been under development in the past few years in which it was qualified for operation in a wide range of discharge currents (0.3-1.2 A), and ignition scenarios. As part of the qualification process the cathode was operated for over 5,000 hours - representative time duration of low power Hall and ion thrusters. In the endurance test floating keeper voltage, ignition voltage and cathode body temperatures were monitored. Floating keeper voltages gradually decreased from 14 v to 8.5 V, throughout the experiment, indicating on suitable cathode operation conditions. All ignition voltages were below 400 V, regardless of the cathode operation history. Cathode body temperatures were stable and below 300°C. At the end of the endurance test the cathode was found to be in a good state with no change to the keeper orifice dimensions (external surface).

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  • A 5,000-hr Heaterless Hollow Cathode Endurance Test

    Dan R. Lev;Gal Alon;Leonid Appel;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Plasma Instabilities in the Plume of a Hollow Cathode

    作者:Marcel P. Georgin;Benjamin A. Jorns;Alec D. Gallimorei; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    Plasma instabilities are spatially characterized in the plume of a 20 A LaB_6 hollow cathode using ion saturation probes. The wave measurements are analyzed using a continuous wavelet transform to decompose the signal into three types of oscillations: 50 kHz, 0.1-0.5 MHz, and 0.8-1.2 MHz. Measurements of the wave amplitude of the 50 kHz oscillation with position show that this instability is localized in the plasma plume and is interpreted as the source for the other instabilities in the plasma. The 0.1-0.5 MHz waves are shown to be dominant near the cathode and are interpreted using ion-acoustic soliton theory. The analytical description of a soliton is in good qualitative agreement the measurement; however, estimates of the width are 1 to 2 orders of magnitude smaller than the observations. Lastly, the waves from 0.8-1.2 MHz are shown to be qualitatively well described by a Gaussian wave packet, though the velocity measured from the dispersion of these waves is too large to be an ion-acoustic wave packet. Together, these measurements support the notion that a localized instability in the cathode plume gives rise to propagating instabilities composed of the natural modes of the plasma including solitons and wave packets.

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  • Plasma Instabilities in the Plume of a Hollow Cathode

    Marcel P. Georgin;Benjamin A. Jorns;Alec D. Gallimorei;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Investigation of Bio-Inspired Pin Geometries for Enhanced Heat Transfer Applications

    作者:Anish Prasad;Yogesh Pai;Osarodion Ogbebor-Evans;Mark Ricklick; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    Circular cylindrical pins are one of the most widely used type in convection cooling systems and profoundly used in the internal cooling of gas turbine blades and other applications, as they promote better heat transfer at the expense of large pressure losses and unsteadiness in the flow. The need to reduce pressure drop and maintain the heat transfer rates are a pressing requirement for a variety of industries to improve the cooling efficiency. One such prominent field of research is conducted in optimizing the design of pin geometries. In this line of research bio-mimicked harbor seal whisker geometry is being validated for their improvement in pumping power requirements and heat transfer rates. The seal whisker geometry consists of stream-wise and span-wise undulations which reduce the size of the wake and coherent structures shed from the body as a result of an added component of stream-wise vorticity along the pin surface. Also, the vortex shedding frequency becomes less pronounced, leading to significantly reduced lateral loading on the modified cylinder. Two different cross-section types; elliptical and circular cross section of the bio inspired pins were created for this investigation. An array of these modified pin geometries is subjected to experimental study, using Temperature Sensitive Paint for temperature measurements on the end wall. The results of the experimental study is then compared with computational results. These findings are important to the gas turbine community as reduced penalties associated with cooling flows directly translate to improved thermodynamic and propulsive efficiencies.

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  • Investigation of Bio-Inspired Pin Geometries for Enhanced Heat Transfer Applications

    Anish Prasad;Yogesh Pai;Osarodion Ogbebor-Evans;Mark Ricklick;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Heat Transfer Measurements in a Leading Edge Cooling Geometry under Rotating Conditions

    作者:Lorenzo Cocchi;Bruno Facchini;Alessio Picchi; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    In this study, a cold bridge type leading edge cooling system has been experimentally investigated, with the aim to determine rotational effects on heat transfer. A radial channel feeds seven circular holes, which in turn generate seven impingement jets in the leading edge inner cavity. The spent coolant flow is extracted by means of five rows of extraction holes, replicating showerhead and film cooling systems. Different mass flow rates are set through the various extraction rows, thus simulating the effect of blade external pressure distribution. Jet Reynolds number ranging from 20,000 to 50,000 have been investigated in static and rotating conditions (corresponding to a jet Rotation number of 0.008). The effect of different jet feeding conditions, representative of hub, midspan and tip section of the blade, has also been analyzed. Measurements have been carried out exploiting a transient technique with thermochromic liquid crystals. In order to respect the correct sign of buoyancy forces, the test is performed by uniformly heating up the test article with a small amount of mass flow rate, and then by recording the surface response to a sudden decrease in air temperature (down to ambient value) and increase in mass flow rate (up to the nominal value). The obtained results show that jet Reynolds number is the main driving parameter of heat transfer, while jet feeding and extraction conditions effect is limited to the heat transfer pattern shape. In rotating conditions, the interaction between radial residual momentum and Coriolis force on the jet causes a reduction in jet lateral spreading. Moreover, Coriolis forces on the feeding channel appear to disturb the jet generation especially at the blade tip. The combination of these effects causes rotation to have a detrimental effect on heat transfer.

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  • Heat Transfer Measurements in a Leading Edge Cooling Geometry under Rotating Conditions

    Lorenzo Cocchi;Bruno Facchini;Alessio Picchi;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Coupled Heat Transfer Investigation for Turbine Cavity of a Turbojet Engine

    作者:E. Nadir Kacar;Altug Piskin;L. Berrin Erbay; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    In this study, coupled aero-thermal solution is carried out to calculate more accurate metal temperature distribution in the turbine disk cavity of a turbojet engine. The disk cavity contains the intersection of one stator and one rotor domain. During coupled solution process both gas temperature & heat transfer coefficient values and heat flux values are supplied from Computational fluid dynamics (CFD) model while surface temperature values are supplied by Finite element analysis (FEA) model. The iterations begin with uniform gas temperature distribution and certain heat transfer coefficient values calculated using pre-defined correlations as boundary conditions of FEA model. After the metal temperature values generated, .products are used in CFD model. Iterations stop due to convergence criteria regarding metal temperature using an in-house code. The code solves each pre-prepared CFD and FEA models and obtains output then converts into another form that other software can read. Each file form contains coordinates of nodes and the data which are interchanged. The results of the code for the cavity geometry are compared with the ones of current thermal modeling method (FEA) and the test. Tests in the cavity are conducted using thermal paint. As a result of the comparison it seems there is an advantage and minimized error of coupled solution with respect to current FEA model.

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  • Coupled Heat Transfer Investigation for Turbine Cavity of a Turbojet Engine

    E. Nadir Kacar;Altug Piskin;L. Berrin Erbay;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Accuracy of RANS CFD Methods for Design Optimization of Turbine Blade Tip Geometries

    作者:Marek Paty;Sergio Lavagnoli; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    In the never-ending search for higher engine performance, the optimization of the blade tip geometry provides an opportunity to control the tip leakage flow, mitigate the rotor mixing losses and manage the heat load distributions. However, the setup of numerical flow simulations of a high-pressure turbine stage for the purpose of blade tip geometry optimization is subjected to conflicting requirements: the computational demands have to be low enough to run a sufficiently large number of direct evaluations within a limited period of time, whereas the numerical model must guarantee sufficient accuracy in the prediction of the relevant flow physics that drives variations in the performance objectives. This paper evaluates the options for the setup of numerical simulations suitable for CFD-based blade tip optimization and assesses the impact of the CFD methods on the computation accuracy with emphasis on rotor tip flow prediction. The numerical study is performed with the Numeca FINE/Turbo and FINE/Open commercial RANS solvers on a set of optimised blade tip geometries in a high-pressure gas turbine stage. The domain is meshed with either an unstructured or a multi-block structured grid in order to assess the influence of domain discretization methods on performance parameters quantification. The location of the high-pressure stage after the combustor poses increased demands on turbulence modelling due to the high inlet turbulence intensity. This work compares the performance of the one-equation Spalart-Alllmaras (SA) and the two-equation k-ε and k-ω SST. Another section is dedicated to methods for modelling of stator-rotor interaction. Domain restriction to rotor-only is attractive for its low computational demands, but it does not allow to include the stator-rotor interaction effects. This method is compared against a full-stage setup, empolying either the commonly used steady computation with mixing plane or the Non-Linear Harmonics method which allows to capture the unsteady blade-passing effects. The computations are validated by experimental data available from a large scale high-speed turbine facility, employing a rainbow rotor approach to allow the simultaneous aerothermal testing of multiple optimized blade tip geometries.

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  • Accuracy of RANS CFD Methods for Design Optimization of Turbine Blade Tip Geometries

    Marek Paty;Sergio Lavagnoli;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Numerical Modeling of the Combustion Process in Hybrid Rocket Engines using Open Source Software

    作者:Esteban Maya;Jairo A. Valdes; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    Hybrid rocket engines (HRE) are considered one of the new trends in space propulsion systems due to their advantages related to reduced cost, operational safety, throttleability and propulsion capabilities. In order to generate a secure and efficient design of these propulsion systems it is necessary to estimate the thermodynamic properties and chemical composition of products inside the combustion chamber of the system. To achieve this, usually an experimental approach which implies associated experimentation cost is needed. An alternative to reduce development cost in HRE systems is the use of a numerical approach in order pre-design an evaluate different alternative configurations. Therefore an effort to estimate the combustion process numerically is of great importance for the development of this technology. The aim of this paper is to present a methodology for the simulation of combustion process occurring in hybrid rocket engines involving the use of open source software. Numerical results are compare against reported data from a selected test case of gaseous oxygen and high density polyethylene fuel HRE configuration with a relative good agreement. The proposed methodology implements k-ω SST turbulence model and PaSR turbulence-chemistry interaction model within a two step finite reaction rate combustion mechanism coupled with ideal gas assumption. It is expected that the proposed methodology may contribute in future research as a guideline to simulate these type of systems.

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  • Numerical Modeling of the Combustion Process in Hybrid Rocket Engines using Open Source Software

    Esteban Maya;Jairo A. Valdes;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Systematic strategies for thermochemical model reduction in rocket propulsion applications

    作者:P. P. Ciottoli;R. Malpica Galassi;P. E. Lapenna;G. Leccese;D. Bianchi;F. Nasuti;F. Creta;M. Valorani; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    Standard propulsive applications, such as liquid and hybrid rocket engines, are characterized by highly turbulent purely non-premixed flames. Mixing and combustion of propellants occur under severe thermodynamic conditions, and the numerical characterization of such class of devices is made difficult by the highly non linear thermodynamic and transport properties of the reacting mixture. In this framework, reliable simplified/skeletal chemical kinetic mechanisms and accurate calculation of thermochemical properties, are required for high fidelity simulations. With the present work, the well established computational singular perturbation-based simplification strategy, is employed in a broader range of thermodynamical conditions characterized by supercritical pressures. A systematic frame-work for chemical kinetics simplification under supercritical conditions is provided and its capabilities are assessed for paraffin/oxygen flame structures, representative of the combustion processes taking place in paraffin-based hybrid rocket engines. An 18-species skeletal mechanism for paraffin-GOx is obtained starting from a 76-species detailed mechanism.

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  • Systematic strategies for thermochemical model reduction in rocket propulsion applications

    P. P. Ciottoli;R. Malpica Galassi;P. E. Lapenna;G. Leccese;D. Bianchi;F. Nasuti;F. Creta;M. Valorani;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Geometric Swirl Number and Hybrid Rocket Engine Performance

    作者:David R. Greatrix; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    With respect to assessing the performance of hybrid rocket engines that use oxidizer injector swirl to enhance the fuel surface regression rate, the swirl number, S, is commonly quoted as a relevant measure of swirl intensity. The usage of an associate parameter, the geometric swirl number, S_g, is particularly prevalent for a class of engines that employ inward-swirl designs that commonly utilize fully tangential injectors, rather than angled injectors that provide an explicit axial and tangential flow contribution. The original formula for the estimation of the geometric swirl number is entirely a function of the geometry of the injector apparatus, hence potentially explaining some of its subsequent popularity. The purpose of the present investigation is to clarify the limitations of and, with the benefit of hindsight, examine potential pitfalls in regard to relying too heavily on this parameter as a measure of effective combustor swirl intensity. The issue of swirl decaying in strength as one moves downstream in the combustor comes into play as a pivotal factor in this study of S_g. The decay problem appears to be more prevalent with inward-swirl designs, as opposed to outward-swirl designs, which unfortunately further acts to degrade the potential value of S_g as a legitimate measure of net swirl intensity in an engine.

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  • Geometric Swirl Number and Hybrid Rocket Engine Performance

    David R. Greatrix;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Development of a Laser Ignition Scheme for Hybrid Rocket Motors

    作者:David M. Dyrda;Brian J. Cantwell; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    Hybrid rocket motors currently lack options for an ignition system that is both compact enough to be placed on a flight motor and capable of producing motor restarts. Continual advances in laser technology, particularly with respect to semiconductor lasers, have resulted in a wide availability of compact and reliable devices that can continually deliver several watts of optical power. This paper presents a novel concept of a laser igniter for use in hybrid rocket motors, and analyzes the design of such a system, highlighting the major design considerations and key trade-offs. The geometry of the laser optics is considered specifically for small-scale motors, leading to the conclusion that the design is feasible as long as the beam intensity required for ignition is not substantially larger than 10~7 W/m~2. In order to collect data on ignition intensity requirements and assess the feasibility of this laser system over a range of motor operating conditions, an experimental version of this laser igniter is being constructed.

    关键字:

  • Development of a Laser Ignition Scheme for Hybrid Rocket Motors

    David M. Dyrda;Brian J. Cantwell;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

  • Prediction of 3D Boundary Layer Blockage and the Grain Design Optimization of HVT Dual-thrust Hybrid Rockets

    作者:V. R. Sanal Kumar;Vigneshwaran Sankar;Nichith Chandrasekaran;Pavithra Murugesh;Sulthan Ariff Rahman M; 会议名称:AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum 2018年

    An innovative and powerful closed-form analytical model is developed for predicting the 3D boundary layer blockage in high-velocity transient (HVT) dual-thrust hybrid rockets obeying the compressible diabatic viscous flow theory. This is the continuation of our previous connected paper pertaining to the boundary layer blockage prediction at the Sanal flow choking condition for adiabatic flows (V. R. Sanal Kumar et al. [1], AIP Advances, 8, 025315, 2018). The Sanal flow choking for diabatic flow is a unique condition of any internal flow system at which both the thermal choking (Rayleigh flow effect) and the wall-friction induced flow choking (Fanno flow effect) occur at a single sonic-fluid-throat location. A dualthrust hybrid rocket with constant upstream cylindrical port having large length-to-diameter ratio (I/d ≥ 27) is selected as a three-dimensional physical model. During the numerical simulation, for achieving the Sanal flow choking effect the igniter jet Mach number is selected based on the thermal choking condition and the average wall friction coefficient of the cylindrical port is selected based on the Fanno flow model. The beauty and novelty of the Sanal flow choking condition for diabatic flow is that, without missing the real flow physics we could exactly predict the 3D boundary layer blockage of the dual-thrust hybrid rocket motors with different liquid fuel and liquid oxidizer combinations aiming for achieving the highest possible solid fuel or solid oxidizer loading density coupled with high ΔV benefits without creating any internal flow choking effect within the given envelop during the entire period of its operation. We concluded that, though the boundary layer blockage is relatively higher, the liquid oxidizer or liquid fuel with the highest heat capacity ratio is the best choice for increasing the propellant loading density without inviting any undesirable internal flow choking phenomenon leading to catastrophic failures of the rocket motor due to the formation of pressure overshoot as a result of the internal shock waves. Note that the pressure ratio for choking will increase while increasing the heat capacity ratio of the gas. The closed-form analytical model presented herein is a brilliant tool for the validation of 3D Navier-Stokes solvers for the design optimization of any HVT internal flow system involving the transfer of heat with confidence. Furthermore, using the closed-form analytical model at the Sanal flow choking condition for diabatic flows, the HVT rocket designers can accurately predict the possibilities of the internal flow choking in the dual-thrust hybrid rockets at the given jet flow Mach number for a credible decision making for improving its propellant loading density within the given envelope lucratively.

    关键字:

  • Prediction of 3D Boundary Layer Blockage and the Grain Design Optimization of HVT Dual-thrust Hybrid Rockets

    V. R. Sanal Kumar;Vigneshwaran Sankar;Nichith Chandrasekaran;Pavithra Murugesh;Sulthan Ariff Rahman M;

    AIAA/SAE/ASEE joint propulsion conference;AIAA propulsion and energy forum

    2018年

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