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Technical Paper

Heat Transfer characterization of Catalytic Converter Substrates during Warm-up

The transient heat transfer behavior of a real size automotive catalytic reactor has been simulated with OpenFOAM in 1D. The model takes into consideration the gas-solid convective heat transfer, axial wall conduction and heat capacity effects in the solid phase, but also the chemical reactions of CO and C3H6 oxidations, based on simplified Arrhenius and Langmuir-Hinshelwood approaches. The associated parameters have been chosen based on the tuning of experimental data. The impact of different initial catalytic converter temperatures, inlet flow temperatures and inlet flow rates have been quantified, even in terms of overall cumulative emissions. . A dimensional analysis is proposed and dimensionless temperature difference and space-time coordinate are defined. Using this suitably modified coordinates, for the case of negligible axial solid conduction, computed solid temperature at the reactor outlet lay on the typical S-curve.
Technical Paper

Chemical and Physical Characterization of Organic Particulate Matter from Last Generation Exhaust Aftertreatment System of Medium Duty Diesel Engine

Particulate Matter from Euro 6 Medium Duty diesel engine was analyzed from engine-out, downstream of particulate filter (DPF), and up to the exit of a selective catalytic reactor (SCR) to characterize its chemical and physical nature. Particular attention was devoted to the analysis of particles down to 23 nm. An array of chemical, physical and spectroscopic techniques (Gas chromatography coupled with mass spectrometry (GC-MS), mobility analyzer, UV-visible absorption and fluorescence spectroscopy) was applied for characterizing the organic particulate matter (PM, constituted of polycyclic aromatic hydrocarbons (PAH), heavy aromatic compounds, soot) in the exhaust. The engine was operated at “full-load” (100% of the total power, representing the best performance of the engine operation) condition, and at different engine speeds. Results showed that the DPF efficiency was greater than 96% in the reduction of the sub 23 nm particles across the speeds range.
Technical Paper

Effects of In-cylinder flow structures on soot formation and oxidation in a swirl-supported light-duty diesel engine

In this paper, computation fluid dynamics (CFD) simulations are performed to describe the effect of in-cylinder flow structures on the formation and oxidation of soot in a swirl-supported light-duty diesel engine. The focus of the paper is on the effect of swirl motion and injection pressure on late cycle soot oxidation. The structure of the flow at different swirl numbers is studied to investigate the effect that varying swirl number imposes on the coherent flow structures. These coherent flow structures are studied to understand the mechanism that leads to efficient soot oxidation in late cycle. Effect of varying injection pressure at different swirl numbers and the interaction between spray and swirl motions are discussed. The complexity of diesel combustion, especially when soot and other emissions are of interest, requires using a detailed chemical mechanism to have a correct estimation of temperature and species distribution.
Technical Paper

Runway Deicing Product Anti/Deicing Performance Assessment: Review and Future Directions

Every winter, northern airport operations are disrupted by heavy snowstorms and freezing precipitations. A simple snow accumulation or a thin layer of ice can affect aircraft operations (take-off, landing and taxi), and increase the risk for passengers and crew members, by rendering the runway slippery. Any deficits in deicing operations can also lead to flight delays and even cancellations that cost a lot to the industry. In order to maintain the runway and taxiway in a safe and useable condition, airport authorities use mechanical tools, but also chemical products. Chemical products available on the market for use in airports are principally in solid forms and liquid form, and are denominated as Runway Deicing Product (RDP).

Glossary of Carbon Steel Sheet and Strip Terms

This glossary is intended to provide engineers, metallurgists, and production personnel with uniform definitions of commonly used carbon sheet and strip terms. The glossary serves to supplement information and photographs reported in SAE J810, J763, J877, J863, and J403. Many of the terms listed apply only to hot-dipped zinc-coated products or to uncoated products. The letter C following the term identifies a term applying to coated materials, while the letters NC identify a term applying to uncoated materials. Where no identification is provided, the term is common to both.

Titanium Alloy Bars, Forgings and Forging Stock, 3.0Al - 2.5V, Annealed

This specification covers a titanium alloy in the form of bars up through 1.000 inch (25.40 mm) in diameter or least distance between parallel sides, inclusive, forgings of thickness up through 1.000 inch (25.40 mm), inclusive, high strength fastener stock up through 1.250 inch (31.75 mm), inclusive, and stock for forging of any size.

Silicone Rubber, 1000 Psi (6.89 Mpa) Minimum Tensile Strength, 55-65 Durometer

This specification covers a silicone rubber material that can be used to manufacture product in the form of sheet, strip, tubing, molded shapes, and extrusions. This specification should not be used to address products such as O-rings, compression seals, O-ring cord, and molded-in-place gaskets.