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Exploration of Cavitation-suppressing Orifice Designs for a Heavy-duty Diesel Injector Operating with Straight-Run Gasoline

Aramco Research Center - Detroit-Yuanjiang Pei, Michael L. Traver
Argonne National Laboratory-Roberto Torelli, Gina M. Magnotti, Sibendu Som
  • Technical Paper
  • 2019-24-0126
To be published on 2019-08-15 by SAE International in United States
The occurrence of cavitation inside injectors is generally undesirable since it can cause material erosion and result in deviations from the expected operating conditions and performance. Previous numerical work employing an injector geometry measured with x-ray diagnostics and operating with a high-volatility straight-run gasoline has shown that: (1) most of the cavitation is generally observed at low needle lifts, (2) needle motion is responsible for asymmetric structures in the internal flow as well as large pressure and velocity gradients that trigger phase transition at the orifice inlets, and (3) cavitation affects the injector discharge coefficient and distribution of injected fuel. To explore the potential for material damage within the injector orifices due to cavitation cloud collapse, the cavitation-induced erosion risk assessment (CIERA) tool has been applied for the first time to the realistic geometry of a heavy-duty injector using the CONVERGE software. Critical locations with high erosive potential matched qualitatively well with x-ray scans of an eroded injector sample that underwent a durability test with straight-run gasoline. This motivated a CFD exploration of a series…
 
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INSTALLING AND REMOVAL TOOLS, CONNECTOR ELECTRICAL CONTACT, TYPE I, CLASS 1, COMPOSITION A

AE-8C2 Terminating Devices and Tooling Committee
  • Aerospace Standard
  • AS81969/33
  • Current
Published 2019-06-14 by SAE International in United States
No Abstract Available.
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INSTALLING AND REMOVAL TOOLS, CONNECTOR ELECTRICAL CONTACT, TYPE II, CLASS 1, COMPOSITION A (FOR MIL-DTL-28840 CONNECTORS)

AE-8C2 Terminating Devices and Tooling Committee
  • Aerospace Standard
  • AS81969/34
  • Current
Published 2019-06-14 by SAE International in United States
No Abstract Available.
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Titanium Alloy Bars, Forgings, and Rings, 6Al - 4V Extra Low Interstitial (ELI), Duplex Annealed, Fracture Toughness

AMS G Titanium and Refractory Metals Committee
  • Aerospace Material Specification
  • AMS4931F
  • Current
Published 2019-06-11 by SAE International in United States

This specification covers a titanium alloy in the form of bars 6.000 inches (152.40 mm) and under in nominal diameter or least distance between parallel sides, forgings and flash welded rings 6.000 inches (152.40 mm) and under in thickness, and stock for forging and stock for flash welded rings of any size.

 
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A Novel Heating-Coating Hybrid Strategy for Wind Turbine Icing Mitigation

Iowa State University-Linyue Gao, Liqun Ma, Yang Liu, Hui Hu
Published 2019-06-10 by SAE International in United States
The electro-thermal method is most commonly used for wind turbine anti-/de-icing. The upmost drawback of such systems is the high power consumption. In the present study, we proposed to use a durable slippery liquid-infused porous surface (SLIPS) to effectively reduce the power requirement of the heating element during the anti-/de-icing process. The explorative study was conducted in the Icing Research Tunnel at Iowa State University (ISU-IRT) with a DU91-W2-250 wind turbine blade model exposed under severe icing conditions. During the experiments, while a high-speed imaging system was used to record the dynamic ice accretion process, an infrared (IR) thermal imaging system was also utilized to achieve the simultaneous surface temperature measurements over the test model. In comparison to the traditional electrical heating strategies to brutally heat massive area of entire turbine blades, a novel heating-coating hybrid strategy, i.e., combining a leading-edge (LE) heating element to cover the first 30% of the chord length (C) along with using SLIPS to coat entire blade surface, was found to be able to keep the entire blade surface completely…
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Utilization of Single Cantilever Beam Test for Characterization of Ice Adhesion

Iowa State University-Bishoy Dawood, Denizhan Yavas, Christopher Giuffre, Ashraf Bastawros
Published 2019-06-10 by SAE International in United States
Many engineering systems operating in a cold environment are challenged by ice accretion, which unfavorably affects their aerodynamics and degrades both their performance and safety. Precise characterization of ice adhesion is crucial for an effective design of ice protection system. In this paper, a fracture mechanics-based approach incorporating single cantilever beam test is used to characterize the near mode-I interfacial adhesion of a typical ice/aluminum interface with different surface roughness. In this asymmetric beam test, a thin layer of ice is formed between a fixed and elastically deformable beam subjected to the applied loading. The measurements showed a range of the interfacial adhesion energy (GIC) between 0.11 and 1.34 J/m 2, depending on the substrate surface roughness. The detailed inspection of the interfacial ice fracture surface, using fracture surface replication technique, revealed a fracture mode transition with the measured macroscopic fracture toughness. The higher level of fracture toughness was associated with cohesive-type interfacial failure. The lower level of fracture toughness on smoother surfaces was associated with adhesive interface failure.
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An Experimental Study to Evaluate the Droplet Impinging Erosion Characteristics of an Icephobic, Elastic Soft Surface

Iowa State University-Liqun Ma, Zichen Zhang, Yang Liu, Hui Hu
Published 2019-06-10 by SAE International in United States
Elastic soft material/surface, such as Polydimethylsiloxane (PDMS), is a perspective, useful and low-cost hydrophobic and icephobic coating. While it has been reported to have good mechanical durability, its erosion durability under the high impacting of water droplets pertinent to aircraft inflight icing phenomena has not been explored. In this study, the droplet imping erosion characteristics of an icephobic PDMS surface/material is evaluated systematically upon the dynamic impinging of water droplets at different impact velocities (~ up to 75m/s), in comparison with other state-of-the-art icephobic materials/surfaces, such as superhydrophobic surface (SHS) and slippery liquid-infused porous surface (SLIPS). Surprisingly, the contact angle (CA) of the elastic PDMS is shown to have an over 20° increase (from 105° to 128°), which represents better hydrophobicity, after the erosion test which is mainly contributed to the higher roughness of the eroded PDMS surface. As for the icephobicity evaluation, intact PDMS was found to has ultra-low ice adhesion (~8 kPa), in comparison with SHS (i.e., ~100kPa) and SLIPS (i.e., ~35kPa). PDMS also shows outstandingly stable ice adhesion during the erosion test…
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Gear System Parameters and Its Influence on Gearbox Noise

General Motors Technical Centre India-Yogesh Kumar Dewangan, Pranoy Sureshbabu Nair, Dipin Nair
Published 2019-06-05 by SAE International in United States
Tonal noise due to gears is one of the fundamental noise problems in a gearbox. Gear tooth deflections generate dynamic forces that lead to unwanted load fluctuations, thus noise. Different factors that are considered to control this noise, some to mention like proper gear macro design, microgeometry corrections, and housing compliance. However, identifying the appropriate variable as a measure of contribution to the overall response helps in getting more accurate remedial solutions. Some outputs to track are different harmonic components of TE, temperature effects, components of forces, rim compliance and friction.For evaluation, usually, the amplitudes of individual harmonics of transmission error are related to the respective orders of the noise levels assuming it as one of the primary excitation parameters of gear noise. In this paper, a brief overview of TE and its harmonic distribution is discussed with the example of an ideal gear mesh model and then quantifying TE with the introduction of mesh misalignment. The effect of providing additional microgeometry corrections to compensate for the misalignment is also discussed.The study in this paper…
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Design Software Identifies a Product's Performance Tradeoffs

  • Magazine Article
  • TBMG-34602
Published 2019-06-01 by Tech Briefs Media Group in United States

Designing any product — from complex car parts to wrenches — is a balancing act with conflicting performance tradeoffs. Making something lightweight, for instance, may compromise its durability.

 
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Eyes in the Sky

Aerospace & Defense Technology: June 2019

  • Magazine Article
  • 19AERP06_01
Published 2019-06-01 by SAE International in United States

Rugged High-Speed Cameras Capture Critical Flight Test Video Data

There is increasing demand for high-quality High Definition (HD) video for airborne applications such as Flight Test Instrumentation (FTI). Ideally, such new camera solutions can reduce the weight and difficultly of installing wiring, and enable data to be coherently combined with image data. Ethernet cameras can address these needs with built-in compression and multiple output streams. Additionally, as Ethernet-based networks have become an attractive choice for FTI applications, we see increased requirements for integrating Ethernet-based cameras with FTI data acquisition equipment, network recorders, and telemetry systems as this removes duplication of wiring and devices.

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