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Process Regulations and Mechanism of WEDM of Combustor Material

SAE International Journal of Aerospace

National Institute of Technology, Kurukshetra, India-Bhupinder Singh, Joy Prakash Misra
  • Journal Article
  • 01-12-01-0004
Published 2019-06-07 by SAE International in United States
This study discusses the experimental investigation on WEDM of combustor material (i.e., nimonic 263). Experimentation has been executed by varying pulse-on time (Ton), pulse-off time (Toff), peak current (Ip), and spark gap voltage (Sv). Material removal rate (MRR), surface roughness (SR), and wire wear rate (WWR) are employed as process performance characteristics. Experiments are designed as per the box-Behnken design technique. Parametric optimization has also been performed using response surface methodology. Besides this, field-emission scanning electron microscope (FE-SEM) and an optical microscope are utilized to characterize WEDMed and worn-out wire surfaces. It is observed that both surfaces contain micro-cracks, craters, spherical droplets, and a lump of debris. Furthermore, the mechanism of recast layer formation has been critically evaluated to apprehend a better understanding of the technique. The key features of the experimental procedure are also highlighted.
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Design and Experiment on Aircraft Electromechanical Actuator Fan at Different Altitudes and Rotational Speeds

SAE International Journal of Aerospace

Air Force Research Laboratory, USA-Q.H. Leland
North Carolina A&T State University, USA-E. Gyasi, J.P. Kizito
  • Journal Article
  • 01-12-01-0003
Published 2019-06-07 by SAE International in United States
For electromechanical actuators (EMAs) and electronic devices cooling on aircraft, there is a need to study cooling fan performance at various altitudes from sea level to 12,000 m where the ambient pressure varies from 1 to 0.2 atm. As fan static pressure head is proportional to air density, the fan’s rotational speed has to be increased significantly to compensate for the low ambient pressure of 0.2 atm at the altitude of 12,000 m. To evaluate fan performance for EMA cooling, a high-rotational-speed, commercially available fan made by Ametek with a diameter of ~82 mm and ~3 m3/min zero-load open cooling flow rate when operating at 20,000 rpm was chosen as the baseline. According to fan scaling laws, this fan was expected to meet the cooling needs for an EMA when operating at 0.2 atm. Using a closed flow loop, the performance of the fan operating in the above ambient pressure range and at a rotational speed between 15,000 and 30,000 rpm was evaluated. Unexpectedly, at 0.2 atm, the Ametek fan was able to produce only…
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High Power-Density, High Efficiency, Mechanically Assisted, Turbocharged Direct-Injection Jet-Ignition Engines for Unmanned Aerial Vehicles

SAE International Journal of Aerospace

Ton Duc Thang University, Vietnam-Alberto Boretti
  • Journal Article
  • 01-12-01-0002
Published 2019-05-02 by SAE International in United States
More than a decade ago, we proposed combined use of direct injection (DI) and jet ignition (JI) to produce high efficiency, high power-density, positive-ignition (PI), lean burn stratified, internal combustion engines (ICEs). Adopting this concept, the latest FIA (Fédération Internationale de l’Automobile) F1 engines, which are electrically assisted, turbocharged, directly injected, jet ignited, gasoline engines and work lean stratified in a highly boosted environment, have delivered peak power fuel conversion efficiencies well above 46%, with specific power densities more than 340 kW/liter. The concept, further evolved, is here presented for unmanned aerial vehicle (UAV) applications. Results of simulations for a new DI JI ICE with rotary valve, being super-turbocharged and having gasoline or methanol as working fuel, show the opportunity to achieve even larger power densities, up to 430 kW/liter, while delivering a near-constant torque and, consequently, a nearly linear power curve over a wide range of speeds.
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Landing Response Analysis on High-Performance Aircraft* Using Estimated Touchdown States

SAE International Journal of Aerospace

Aeronautical Development Agency, India-P.S. Suresh, Niranjan Kumar Sura
Indian Institute of Technology Madras, India-K. Shankar
  • Journal Article
  • 01-12-01-0001
Published 2019-04-08 by SAE International in United States
A novel use of state estimation methods as initial input for a landing response analysis is proposed in this work. Six degrees of freedom (DOF) non-linear landing response model is conceived by considering longitudinal dynamics of aircraft as a rigid body with heave-and-pitch motions coupled onto a bicycle landing gear† arrangement. The DOF for each landing gear consist of vertical and longitudinal motions of un-sprung mass, considering strut bending flexibility. The measurement data for state estimation is obtained for three landing cases using non-linear flight mechanics model interfaced with pilot-in-loop simulation. State estimation methods such as Upper Diagonal Adaptive Extended Kalman Filter (UD-AEKF) with fuzzy-based adaptive tuning and Un-scented Kalman Filter (UKF) were adapted for landing maneuver problem. On the basis of estimation error metrics, aircraft state from UKF is considered during onset of touchdown. These estimated states are used as an initial condition for the six DOF non-linear landing response model, numerically solved in Matlab environment. The dynamic responses such as displacement, velocity, and acceleration for the aircraft and the loads on landing gears…
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Mapping of Fuel Anti-Knock Requirements for a Small Remotely Piloted Aircraft Engine

SAE International Journal of Aerospace

Air Force Institute of Technology-Joseph K. Ausserer, Marc D. Polanka
Air Force Research Laboratory-Paul Litke
  • Journal Article
  • 2016-32-0045
Published 2016-11-08 by SAE International in United States
Small remotely piloted aircraft (10-25 kg) powered by internal combustion engines typically operate on motor gasoline, which has an anti-knock index (AKI) of >80. To comply with the single-battlefield-fuel initiative in DoD Directive 4140.25, interest has been increasing in converting the 1-10 kW power plants in the aforementioned size class to run on lower AKI fuels such as diesel and JP-8, which have AKIs of ~20. It has been speculated that the higher losses (short-circuiting, incomplete combustion, heat transfer) that cause these engines to have lower efficiencies than their conventional-scale counterparts may also relax the fuel-AKI requirements of the engines. To investigate that idea, the fuel-AKI requirement of a 3W-55i engine was mapped and compared to that of the engine on the manufacturer-recommended 98 octane number (ON) fuel. The knock limit was established to be a peak-pressure rise rate of 5 bar/deg or a maximum amplitude of pressure oscillations of 5 bar for 1% of 400 consecutive cycles, whichever was more conservative. The 3W-55i engine was able to develop full power at all speeds above…
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