Browse Topic: Propellers and rotors

Items (303)

Operating Characteristics of an Automotive Adjustable-Field Permanent Magnet Motors with 3D Magnetic Paths and Asymmetric Magnet Arrangement

2024-32-002704/18/2025

This paper describes a three-dimensional structure of an adjustable field magnetization permanent magnet (PM) motor and a high-power density rotor structure with asymmetric permanent magnet arrangement for both high torque and high efficiency operation in the high speed and low torque range. 3D-FEA has confirmed that it is possible to achieve both high torque density and adjustable field magnetization. Load testing using the prototype proposed motor confirmed that high motor efficiency can be achieved even during high-speed operation.

Hiyoshi, Yutaro, Doi, Kotaro, Noguchi, Toshihiko

Measurement uncertainty and its influence on e-Drive optimization applications

2024-26-009701/16/2024

This paper gives insights in the theoretical measurement uncertainty of E-Drive rotor position dependent results, like Id and Iq calculations, done by a modern propulsion power analyzer (PA). The calculation of Id and Iq is fundamental to perform control optimization and application tasks for an E-Drive system. In order to optimize the E-Drive system application towards e.g. best efficiency, best performance, or improved NVH the importance of the testing toolchain is described: a power analyzer delivering the required results, an automation system, and a Design of Experiment tool to set improved target values. Consequently, inverters applications featuring field-oriented control (FOC) with permanent magnet synchronous machines (PMSM) are updated with a chosen control strategy. For achieving a certain behavior of an E-Drive, different degrees of freedom in the Inverter Control Unit are available; Lookup tables Id and Iq represent two fundamental application labels to be considered

Platzer, Thomas, Fechter, Michael, Kammerstetter, Heribert, Kolb, Philipp

An Aerodynamic Equation of State—Part I: Introduction and Aerospace Applications - QA Test Tatsiana

01-17-01-0001

04/19/2023

Abstract In subsonic aircraft design, the aerodynamic performance of aircraft is compared meaningfully at a system level by evaluating their range and endurance, but cannot do so at an aerodynamic level when using lift and drag coefficients, CL and CD , as these often result in misleading results for different wing reference areas. This Part I of the article (i) illustrates these shortcomings, (ii) introduces a dimensionless number quantifying the induced drag of aircraft, and (iii) proposes an aerodynamic equation of state for lift, drag, and induced drag and applies it to evaluate the aerodynamics of the canard aircraft, the dual rotors of the hovering Ingenuity Mars helicopter, and the composite lifting system (wing plus cylinders in Magnus effect) of a YOV-10 Bronco. Part II of this article applies this aerodynamic equation of state to the flapping flight of hovering and forward-flying insects. Part III applies the aerodynamic equation of state to some well-trodden cases in fluid

Burgers, Phillip

An Aerodynamic Equation of State—Part I: Introduction and Aerospace Applications - QA Test Tatsiana

01-17-01-0001-TEST-REC04/19/2023

Burgers, Phillip

An Aerodynamic Equation of State—Part I: Introduction and Aerospace Applications

01-17-01-0001

04/19/2023

In subsonic aircraft design, the aerodynamic performance of aircraft is compared meaningfullyby evaluating their range and endurance, but cannot do so atwhen using lift and drag coefficients,and, as these often result in misleading results for different wing reference areas. This Part I of the article (i) illustrates these shortcomings, (ii) introduces a dimensionless number quantifying the induced drag of aircraft, and (iii) proposes anfor lift, drag, and induced drag and applies it to evaluate the aerodynamics of the canard aircraft, the dual rotors of the hoveringMars helicopter, and the composite lifting system (wing plus cylinders in Magnus effect) of a YOV-10. Part II of this article applies this aerodynamic equation of state to the flapping flight of hovering and forward-flying insects. Part III applies the aerodynamic equation of state to some well-trodden cases in fluid mechanics found in fluid-mechanics textbooks.

Burgers, Phillip

Re-imagining Brake Rotor Thermal Fatigue Testing to Relate to Field Use

2022-01-116309/19/2022

The validation of brake rotors has remained, to this day, heavily reliant on “Thermal Abuse” or “Thermal Cracking” type testing, with many procedures so dated that most engineers active in the industry today cannot even recall the origin of the test. These procedures - of which there are many variants - all share the trait of greatly accelerating durability testing by performing repeated high power (high speed and high deceleration) brake applies to drive huge temperature gradients and internal stress, and often allowing the rotor to get very hot, to where the strength of the material from which the rotor is constructed is significantly degraded. There is little debate about whether these procedures work; by and large rotor durability issues in the field are extremely rare. However, without the connection to the duty cycle in the field, it is extremely difficult to interpret results (especially since many standards allow significant cracking before a failure is declared), and this can

Antanaitis, David, Langhardt, Jerry

Design and Computational Investigations of Aerobot for Titan with maneuverability using momentum wheel and propeller equipped with droppable weather stations

2022-26-119105/26/2022

Titan, Saturn’s largest moon and the only celestial body which is found to have a landmass composed of liquid hydrocarbons. Nitrogen – The building block of all life that exists on earth is found to be abundant in Titan’s atmosphere of up to 97%. Aerobots provide a great platform for exploring a celestial body with an atmosphere such as Titan. They have modest power requirements, longer mission duration, and can cover a longer distance in a shorter time. They are powered by Radioisotope Thermoelectric Generator for optimal mission life. Aerobot’s altitude can be altered by varying the temperature of the air inside the balloon and yaw can be controlled using Reaction Wheel and a motor-driven propeller for forwarding thrust. The proposed Aerobot will be equipped with four miniature deployable fixed weather stations that can be dropped from the aerobot to titan’s surface. They can be deployed at diverse locations such as the equator and Polar Regions to deeply explore the Titan’s climate

Raja, Manoj Kumar, Sivasankaran, Abinash Nataraj, Saravana Mohan, Haribalan, Thangavel, Sabari, R, Vijayanandh, Gnanasekaran, Raj Kumar

Design and Parametric Investigations on Various Propellers for Nature Inspired Unmanned Amphibious Vehicle

2022-26-117405/26/2022

Unmanned Amphibious Vehicle (UAV) is an integrative working environments based vehicle, which doesn’t allocate the place for onboard pilots. Mostly, unmanned amphibians have been controlled through pre-provided algorithms in the predestined paths. Aerodynamic and hydrodynamic working conditions are the compositions of aforesaid integrative environments, wherein the possible lifespan affecting failure of UAV may chance to happen in a high manner. Thus, the multidisciplinary investigation on UAV and it's every component needs to be done in order to pick the suitable UAV parts for both missions executing conditions. This work deals the comprehensive computational investigations on a different number of blades equipped propellers for the proposed cum nature-inspired UAV under aerodynamic and hydrodynamic loading conditions. Three different propellers are uniquely constructed based on the aerodynamic environment reference with the guidance of analytical formulae and thereafter modeling

R, Vijayanandh, Mathaiyan, Vijayakumar, Raji, Arul Prakash, Madasamy, Senthil Kumar, Gnanasekaran, Raj Kumar

Augmentation of Gas-Turbine Performance Using Inlet Air Cooling and Turbine Blade Cooling: A Thermodynamic Approach

2021-01-003103/02/2021

A systematic and comprehensive first law analysis of a cooled gas turbine cycle subjected to vapor compressor inlet air cooling (VC-IAC) has been conducted in our study. Film air cooling technique has been implemented to cool the gas turbine (GT) buckets. The gas turbine is subjected to variation of various operating and ambient parameters and the corresponding effect is analyzed to find out the optimal one. The integration of VC-IAC has been reported to further enhance the plant specific work and plant efficiency of gas turbine cycle, the enhancement being higher in regions having a hot and dry climate. This increase in cycle performance due to VC-IAC has been found superior in case of bucket cooled GT cycle when compared to uncooled one. It has further been witnessed that the plant specific work increases by more than 0.35 % and the plant efficiency increases by little above 0.1 % for every 1o C drop in CIT. The work ratio representing the excess of work of turbine over work of

Mishra, Alok, Srivastava, Anshuka, Mohapatra, Alok Kumar

Designation of Direction of Rotation of Helicopter Rotors

ARP570B (Current)

01/14/2021

S-12 Powered Lift Propulsion Committee

Multirotor Aircraft Noise Reduction

TBMG-3820112/01/2020

Noise produced by multirotor vehicles may be objectionable to some, especially as industry moves toward drone deliveries and potentially air taxi operations. Multirotor aircraft typically create a significant amount of tonal noise from each rotor. Groups of rotors operating at the same rotation rate with an appropriate phase offset can be used to reduce the tonal noise of the aircraft when there are multiple rotors on each side of the aircraft. Reducing tonal noise, depending on the aircraft design, can effectively reduce the total noise output for a given flight scenario.

Minimization of Electric Heating of the Traction Induction Machine Rotor

2020-01-056204/14/2020

The article solves the problem of reducing electric power losses of the traction induction machine rotor to prevent its overheating in nominal and high-load modes. Electric losses of the rotor power are optimized by the stabilization of the main magnetic flow of the electric machine at a nominal level with the amplitude-frequency control in a wide range of speeds and increased loads. The quasi-independent excitation of the induction machine allows us to increase the rigidity of mechanical characteristics, decrease the rotor slip at nominal loads and overloads and significantly decrease electrical losses in the rotor as compared to other control methods. The article considers the technology of converting the power of individual phases into a single energy flow using a three-phase electric machine equivalent circuit and obtaining an energy model in the form of equations of instantaneous active and reactive power balance. The quasi-independent excitation of the induction machine is

Nikiforova, Elena, Smolin, Victor, Gladyshev, Sergey

Coiled Spring Pins

20AERP04_0104/01/2020

What Do They Do? How Do You Install Them? Of the hundreds of different types of fasteners used within the aerospace industry, the coiled spring pin was specifically invented as a solution to a “pinning” issue related to securing jet engine turbine blade assemblies back in the 1940s. No other fastener (pin, bolt, rivet, etc.) was strong enough to resist the forces generated during use that was also flexible enough to enable the pin to absorb shock and vibration to isolate the loads from the host material. It is this unique combination of strength and flexibility that enables the coiled pin to preserve the integrity of the hole and ensure that assemblies subject to dynamic loading stay intact. Today, coiled spring pins are used extensively throughout the aerospace industry for a wide variety of purposes. They are used to fasten two or more components together within evacuation slide mechanisms and cargo straps; they are used as hinge pins within interior latch mechanisms in overhead bin

How to Install Coiled Spring Pins

TBMG-3660404/01/2020

Performance of Isolated UAV Rotors at Low Reynolds Number

2020-01-004603/10/2020

Vertical takeoff and landing vehicle platforms with many small rotors are gaining importance for small UAVs as well as distributed electric propulsion for larger vehicles. To predict vehicle performance, it must be possible to gauge interaction effects. These rotors operate in the less-known regime of low Reynolds number, with different blade geometry. As a first step, two identical commercial UAV rotors from a flight test program are studied in isolation, experimentally and computationally. Load measurements were performed in Georgia Tech’s 2.13 m × 2.74 m wind tunnel. Simulations were done using the RotCFD solver which uses a Navier-Stokes wake computation along with rotor-disc loads calculation using low-Reynolds number blade section data. It is found that in hover, small rotors available in the market vary noticeably in performance at low rotor speeds, the data converging at higher RPM and Reynolds number. This is indicative of the high sensitivity of low-Re rotor flows to minor

Tomar, Yashvardhan, Shukla, Dhwanil, Komerath, Narayanan

Performance of Isolated UAV Rotors at Low Reynolds Number

2020-01-004603/10/2020

Tomar, Yashvardhan, Shukla, Dhwanil, Komerath, Narayanan

Plasma Generator Using Spiral Conductors

TBMG-3370302/01/2019

NASA's Langley Research Center has developed a patented SansEC sensor technology for use in many different areas, including tall structures and wind turbines. The SansEC technology is a proven wireless sensing platform capable of measuring the electrical impedance of physical matter in proximity to the sensor based on a change in its resonance response. The SansEC sensor also exhibits a unique characteristic to disperse the lightning strike current to help mitigate lightning damage. In a turbine blade application, an array of SansEC sensors will cover the surface area of the composite blade, providing both lightning mitigation and damage sensing. NASA Langley is seeking industrial partners/licensees to commercialize this technology. The research team at NASA Langley is available to assist with further development.

Modular, Multi-Mode-Propulsion, Unmanned Aerial Concept

TBMG-3362001/01/2019

NASA's Langley Research Center has developed an unmanned aerial vehicle concept for long-range, distributed aerial presence and delivery applications. This aircraft concept is capable of delivering multiple independent payloads over a range of more than 60 miles. The aircraft concept consists of two sub-aircraft: a “mother” vehicle and several “children” vehicles. The mother and children vehicles may operate both independently of one another and as a composite assembly. When not assembled, the mother and children vehicles rely on embedded ducted rotors for vertical lift and general propulsion.

Variable-Pitch Turbine Blades

TBMG-3341012/01/2018

Gas turbine blades of conventional rotorcraft turboshaft engines are optimized to operate at nearly a fixed speed and a fixed incidence angle. If the operating condition of the engine changes, then the flow through the turbine may need to be guided to a more optimum direction.

Propeller Shaft Ends - Dual Rotation (Engine Supplied Bearing)

AIR18B (Current)11/28/2018

This SAE Aerospace Information Report (AIR) records the results of an investigation of a dual rotation propeller shaft standard for an engine supplied bearing and the reason for deciding that such a bearing is impracticable.

E-25 General Standards for Aerospace and Propulsion Systems

Propeller Shaft Torque Ratings

ARP373C (Current)11/28/2018

E-25 General Standards for Aerospace and Propulsion Systems

Design, Development and Integration of a Wing-Morphing, Bimodal Unmanned Vehicle

2018-01-196010/30/2018

This paper relates to the design and development of a multi-modal UAV capable of aerial flight and underwater propulsion. A novel hybrid propulsion system has been manufactured and tested. Consisting of folding blades, the propeller has been optimized for propulsion both in air and water. The critical water to air transition phase is achieved by an additional impulsive thruster powered by a C02 cartridge. To decrease the drag in underwater cruise and reduce the potential damage when the vehicle impacts the water, a morphing wing has been developed. This consists of foam-carbon fiber lay-up constructed wings in a variable sweep configuration. The actuation of the sweep is achieved by linear servos mounted on the sleeve shaped spar. An integrated prototype is constructed, using an unconventional, anhedral horizontal stabilizers to allow clearance for the morphing wing. Using a combination of data taken from wind tunnel testing, CFD simulation and analytic methods, models of the vehicles

Simpson, Mark, Guo, Dian

BEARINGS, PLAIN, SELF-ALIGNING, SELF-LUBRICATING, 300 CPM (13 FPM) OSCILLATION, -65 TO +160 °F, LINERS LESS THAN .015 INCH THICK

AS82819/1 (Current)08/23/2018

ACBG Plain Bearing Committee

Propeller Hub-Single Rotation

AS180B (Current)06/18/2018

E-25 General Standards for Aerospace and Propulsion Systems

Superalloy Surface Treatment for Improved Performance of Power Turbines

TBMG-2833002/01/2018

To produce power more efficiently and cleanly, the next generation of power turbines will have to operate at extreme temperatures and pressures. Currently, single-crystal, nickel-based superalloys are used in such extreme environments. MCrAlY coatings (where M = Co, Ni, or Co/Ni) are widely applied to first- and second-stage turbine blades and nozzle guide vanes, where they may be used as corrosion-resistant overlays or as bond coats for use with thermal barrier coatings.

Study on Nonlinear Rotordynamics Characteristics for Electric Compound Turbocharger

2017-01-241810/08/2017

The electric compound turbocharger(ECT) which integrates a high speed motor into a turbocharger rotor shaft can be used transiently to accelerate the turbocharger more quickly in response to an acceleration requirement. It can utilize the exhaust gas energy fully to improve the engine fuel efficiency and benefit for engine with lower emissions. The key technique of ECT is to solve the reliability problems when an electrical motor is integrated into a turbocharger shaft between the turbine and compressor wheels will increase the burden for the bearing support and affect the turbocharger shaft rotation characteristics. In order to know the dynamics behavior of higher load bearing system is explored for reliability, this paper focus on the nonlinear rotor dynamics characteristics of ECT rotor bearing system. Based on the principle and structure of ECT rotor bearing system, the basic theory method and dynamics model of rotor bearing system is established considered the nonlinear fluid film

Zhang, Hong, Wang, Zhuo, Hong, Zhouzhensen

Efficient Procedure for Robust Optimal Design of Aerospace Laminated Structures

2017-01-205809/19/2017

Innovative aircraft design studies have noted that uncertainty effects could become significant and greatly emphasized during the conceptual design phases due to the scarcity of information about the new aero-structure being designed. The introduction of these effects in design methodologies are strongly recommended in order to perform a consistent evaluation of structural integrity. The benefit to run a Robust Optimization is the opportunity to take into account uncertainties inside the optimization process obtaining a set of robust solutions. A major drawback of performing Robust Multi-Objective Optimization is the computational time required. The proposed research focus on the reduction of the computational time using mathematic and computational techniques. In the paper, a generalized approach to operate a Robust Multi-Objective Optimization (RMOO) for Aerospace structure using MSC software Patran/Nastran to evaluate the Objectives Function, is proposed. A Multi-Objective

Noziglia, Francesco, Rigato, Paolo, Cestino, Enrico, Frulla, Giacomo, Arias-Montano, Alfredo

Time-Varying Loads of Co-Axial Rotor Blade Crossings

2017-01-202409/19/2017

The blade crossing event of a coaxial counter-rotating rotor is a potential source of noise and impulsive blade loads. Blade crossings occur many times during each rotor revolution. In previous research by the authors, this phenomenon was analyzed by simulating two airfoils passing each other at specified speeds and vertical separation distances, using the compressible Navier-Stokes solver OVERFLOW. The simulations explored mutual aerodynamic interactions associated with thickness, circulation, and compressibility effects. Results revealed the complex nature of the aerodynamic impulses generated by upper/lower airfoil interactions. In this paper, the coaxial rotor system is simulated using two trains of airfoils, vertically offset, and traveling in opposite directions. The simulation represents multiple blade crossings in a rotor revolution by specifying horizontal distances between each airfoil in the train based on the circumferential distance between blade tips. The shed vorticity

Komerath, Narayanan, Schatzman, Natasha L., Romander, Ethan A.

Torque Ripple Description and Its Suppression through Flux Linkage Reconstruction

2017-01-907706/17/2017

Description of PMSM torque in high accuracy is critical and previous work for its further research. However, the traditional linear torque model fails to describe its non-ideal characteristics of practical working. This paper presents a generalized torque model of PMSM based on flux linkage reconstruction. In synchronous rotating space coordinates, flux linkage were reconstructed through Fourier series expansion and bivariate polynomial. Based on this model, a precise PMSM torque ripple description and corresponding suppression method were developed. Current feed-forward compensation and the rotor field oriented control were applied in torque ripple suppression. Simulation and experimental results both show that the model not only accurately describes the nonlinear variation of PMSM torque in different working conditions, but also can be used to suppress PMSM torque ripple effectively.

Zhong, Zaimin, Li, Junjie, Zhou, Shuihua, Zhou, Yingkun, Jiang, Shang

Electric Field Activated Shape Memory Polymer Composite

TBMG-2663404/01/2017

NASA’s Langley Research Center has developed a novel shape memory polymer (SMP) made from composite materials for use in morphing structures. In response to an external stimulus such as a temperature change or an electric field, the thermosetting material changes shape, but then returns to its original form once conditions return to normal. Through a precise combination of monomers, conductive fillers, and elastic layers, the NASA polymer matrix can be triggered by two effects — Joule heating and dielectric loss — to increase the response. The new material remedies the limitations of other SMPs currently on the market; namely, the slow stimulant response times, the strength inconsistencies, and the use of toxic epoxies that may complicate manufacturing. NASA has developed prototypes and now seeks a partner to license the technology for commercial applications.

Commando Helicopter

TBMG-2675804/01/2017

Leonardo-Finmeccanica Rome, Italy +39 06 32473313

Self-Excited Wound-Field Synchronous Motors for xEV

2017-01-124903/28/2017

Compact, high efficiency and high reliability are required for an xEV motor generator. IPM rotors with neodymium magnets are widely applied for xEV motors to achieve these requirements. However, neodymium magnet material has a big impact on motor cost and there is supply chain risk due to increased usage of these rare earth materials for future automotive xEV’s. On the other hand, a wound-field rotor does not need magnets and can achieve equivalent performance to an IPM rotor. However, brushes are required in order to supply current to the winding coil of the rotor. This may cause insulation issues on xEV motors which utilize high voltage and high currents. Therefore, it is suggested to develop a system which supplies electric energy to the rotor field winding coil from the stator without brushes by applying a transformer between stator coil and rotor field winding. Specifically, add auxiliary magnetic poles between each field winding pole and wind sub-coils to these poles. The

Seguchi, Masahiro

Time-Dependent Reliability Analysis Using a Modified Composite Limit State Approach

2017-01-020603/28/2017

Recent developments in time-dependent reliability have introduced the concept of a composite limit state. The composite limit state method can be used to calculate the time-dependent probability of failure for dynamic systems with limit-state functions of input random variables, input random processes and explicit in time. The probability of failure can be calculated exactly using the composite limit state if the instantaneous limit states are linear, forming an open or close polytope, and are functions of only two random variables. In this work, the restriction on the number of random variables is lifted. The proposed algorithm is accurate and efficient for linear instantaneous limit state functions of any number of random variables. An example on the design of a hydrokinetic turbine blade under time-dependent river flow load demonstrates the accuracy of the proposed general composite limit state approach.

Majcher, Monica, Mourelatos, Zissimos, Tsianika, Vasiliki

Film Cooled Surface

TBMG-2570211/01/2016

Turbine film cooling flows typically are subject to jet detachment and reduced cooling effectiveness for high blowing rates. Current concepts to improve jet attachment involve impractical or overly complex hole designs due to manufacturing or durability constraints. Novel film cooling concepts from NASA’s Glenn Research Center involve creating a V-shaped recess on the flow surface of a turbine blade to induce fluid, temperature, or shedding effects; threading turbine film cooling holes with helical channels or grooves (much like the threads of a screw) for the purpose of producing a swirling flow of cooling fluid exiting the film cooling hole; and pairing the threaded holes with holes that have an opposite direction of swirl.

Fluidic Oscillator Array for Synchronized Oscillating Jet Generation

TBMG-2551310/01/2016

NASA’s Langley Research Center develops innovative technologies to control fluid flow in ways that will ultimately result in improved performance and fuel efficiency. Often called fluidic oscillators, sweeping jet actuators, or flip flop oscillators, these flow-control devices work based on the Coanda effect. They can be embedded directly into a control surface (such as a wing or a turbine blade) and generate spatially oscillating bursts (or jets) of fluid to improve flow characteristics by enhancing lift, reducing drag, or enhancing heat transfer. Recent studies show up to a 60% performance enhancement with oscillators. NASA offers two new fluidic oscillator designs that address two key limitations of these oscillators: coupled frequency-amplitude and random oscillations. One oscillator effectively decouples the oscillation frequency from the amplitude. The other design enables synchronization of an entire array. The new oscillators have no moving parts — oscillation, decoupling, and

High-Fidelity Transient Thermal Modeling of a Brake Corner

2016-01-192909/18/2016

There is an increasing interest in transient thermal simulations of automotive brake systems. This paper presents a high-fidelity CFD tool for modeling complete braking cycles including both the deceleration and acceleration phases. During braking, this model applies the frictional heat at the interface on the contacting rotor and pad surfaces. Based on the conductive heat fluxes within the surrounding parts, the solver divides the frictional heat into energy fluxes entering the solid volumes of the rotor and the pad. The convective heat transfer between the surfaces of solid parts and the cooling airflow is simulated through conjugate heat transfer, and the discrete ordinates model captures the radiative heat exchange between solid surfaces. It is found that modeling the rotor rotation using the sliding mesh approach provides more realistic results than those obtained with the Multiple Reference Frames method. Because of the significant computational requirements involved, the scope

Kapas, Nimrod, Jayasundera, Ajith

Disc Brake Pad Corrosion Adhesion: Test-to-Field Issue Correlation, and Exploration of Friction Physical Properties Influence to Adhesion Break-Away Force

2016-01-192609/18/2016

Brake pad to rotor adhesion following exposure to corrosive environments, commonly referred to as “stiction”, continues to present braking engineers with challenges in predicting issues in early phases of development and in resolution once the condition has been identified. The goal of this study took on two parts - first to explore trends in field stiction data and how testing methods can be adapted to better replicate the vehicle issue at the component level, and second to explore the impacts of various brake pad physical properties variation on stiction propensity via a controlled design of experiments. Part one will involve comparison of various production hardware configurations on component level stiction tests with different levels of prior braking experience to evaluate conditioning effects on stiction breakaway force. Part two will involve modifying a production friction material formulation with known stiction in the field to force differences in porosity, density, and pH

Robere, Matthew

AS4503-4505 Protection Cap for Propeller Shaft

AS4503-3 (Current)12/04/2015

No scope available.

Engine and Airframe Technical Standards Committee (TSC)

RS269 Standard No. 4/6 Counter Rotating Propeller Shafts (Separate Bearing Race) and Engine Nose

RS269-1 (Current)12/03/2015

No scope available.

Engine and Airframe Technical Standards Committee (TSC)

RS268 Standard No.4/6 Counter Rotating Propeller Shafts (Integral Bearing Race) and Engine Nose

RS268-1 (Current)12/03/2015

No scope available.

Engine and Airframe Technical Standards Committee (TSC)

SPH Simulation of Rivulet Dynamics on Surfaces with Various Wettabilities

2015-01-900509/01/2015

Rivulet dynamics is involved in different scientific problems and industrial applications from production of microchips, to rain flow on structural systems such as wind turbine blades and aircraft wings. In the latter case for example, rivulet flow leads to accumulation of ice on airfoil surface that may affect the aircraft performance. Hence, understanding the dynamics of rivulets is important in solving various scientific problems. In this paper the results of a numerical simulation based on smoothed particle hydrodynamic (SPH) method will be reported on dynamics of rivulets under the effect of various air shear speeds and different surface morphologies. The simulation results will be compared and validated with experiments to shed more lights in understanding the mechanism of shear driven rivulet flow on solid substrates.

Moghtadernejad, Sara, Jadidi, Mehdi, Dolatabadi, Ali, Esmail, Nabil

Improved Attachment Design for Ceramic Turbine Blades Via Hybrid Concepts

TBMG-22550

08/01/2015

This innovation is a hybrid metal-ceramic matrix composite (CMC) turbine blade in which a SiC/SiC CMC airfoil section is bonded to a single-crystal superalloy root section in order to mitigate risks associated with an all-CMC blade inserted in a superalloy disk. This will allow current blade attachment technology (SX blade with a dovetail attachment to a slotted Ni disk) to be used with a ceramic airfoil. The bond between the CMC and single crystal will be primarily mechanical in nature, and enhance with clamping arising from thermal expansion mismatch. Two single-crystal root sections will be bonded to each other using diffusion bonding at temperatures near 1,200 °C. The single crystals will form a clamshell around the CMC, with little or no gap between the metal and ceramic. Upon cooling, the metal will shrink around the CMC to firmly clamp it. It is envisioned that this will allow the blade root to operate at temperatures up to about 800 °C. Single crystals will resist stress

MTU Develops New Turbine Blade Material in Record Time

TBMG-22300

06/01/2015

MTU Aero Engines announced in March that its internal experts and industry partners have jointly developed a new class of intermetallic, high-temperature materials for highly stressed engine components. Named titanium aluminide (TiAl), this new lightweight material is designed for turbine blades and combines the advantages of metallic and ceramic materials.

MEMS Micro-Translation Stage with Large Linear Travel Capability

TBMG-22003

05/01/2015

A MEMS (microelectromechanical systems) micro-translation stage (MTS) with large linear travel capability was developed that uses capacitive electrostatic forces created by stators arranged linearly on both sides of a channel, and matching rotors on a moveable shuttle for precise movement of the shuttle. The device, which is essentially a linear motor built from silicon base with microfabrication techniques, will be able to rapidly translate across large distances using only three-phase power. The moveable shuttle can be as small as 100 mm and can house a variety of elements including lenses and mirrors. The shuttle can be tailored to travel distances as small as 10 mm and as large as 300 mm, with as little as 10 mm between adjacent shuttle stops.