Browse Topic: Particulate matter (PM)
Abstract The paper will provide representative simulations of particle transport around a vehicle in order to investigate some of the issues related to the accurate prediction of emission and transport of particles induced by a moving vehicle with a transverse blowing wind. Special treatments in boundary conditions and wall law function are discussed and applied to maintain the shape of atmospheric boundary layer wind velocity profile. For the vehicle, we adopt the geometry of a Nissan Pathfinder SUV to study the effects of vehicle emission and transport around a moving vehicle. We perform a set of simulations to better understand the modeling requirements for dust emissions including a sensitivity study to determine the modeling parameters that are most important for accurate modeling of dust generation and transport. In particular, we study the effects of location, size distribution, and initial velocity distributions of the modeled dust emissions on predicted downwind atmospheric
Vehicular emissions represent the main responsible of the deterioration of air quality in the urban area. In the attempt to reduce both gaseous emissions and particulates from internal combustion engines, increasingly stricter regulations were introduced from European Union in the last years. These limits have led to the improvement of emissions-reduction technologies as well as the vehicle hybridization and electrification. In this scenario, vehicle emissions due to other sources rather than the propulsion systems, such as brakes and tires, have taken a significant weight. In this regard, European Commission has proposed the introduction in the next EURO 7 standard of the first-ever limit on the particles emitted by vehicle brakes. This study is devoted to improving the knowledge on the particle characteristics due to the brake wear by means of laboratory experiments thus providing support to the definition of the new standards. An experimental layout was realized consisting in a box
This SAE Aerospace Recommended Practice (ARP) details the recommended process for correcting measured non-volatile particulate matter (nvPM) mass and number data for particle losses in the sampling and measurement system specified in ARP6320B. This technique is only recommended for conditions where both nvPM mass and number concentration measurements are in the valid measurement ranges of the instruments that are discussed in the tool limitations section. This ARP also supplies an Excel software tool with documentation to automate the process. The body of this ARP details the recommended calculation method, uncertainties, and limitations of the system loss correction factors. It explains, in detail, the required inputs and outputs from the supplied Excel software tool (developed on Windows 7, Excel 2016). Also included are: The Excel correction tools (refer to Attachments I and V). Installation instructions for a Windows-based computer (refer to Attachment II). A user technical manual
Many performance sport passenger vehicles use drilled or grooved cast iron brake rotors for a better braking performance or a cosmetic reason. Such brake rotors would unfortunately cause more brake dust emission, appearing with dirty wheel rims. To better understand the effects of such brake rotors on particle emission, a pin-on-disc tribometer with two particle emission measurement devices was used to monitor and collect the emitted airborne particles. The first device was an aerodynamic particle sizer, which is capable of measuring particles ranging from 0.5 to 20 μm. The second device was a condensation particle counter, which measures and collects particles from 4 nm to 3 μm. The testing samples were scaled-down brake discs (100 mm in diameter) against low-metallic brake pads. Two machined surface conditions (plain and grooved) with uncoated or ceramic-coated friction surfaces were selected for the investigation. The results showed that the grooved friction surface led to a higher
This ARP describes recommended sampling conditions, instrumentation, and procedures for the measurement of nonvolatile particle number and mass concentrations from the exhaust of aircraft gas turbine engines. Procedures are included to estimate sampling system loss performance. This ARP is not intended for in-flight testing, nor does it apply to engines operating in the afterburning mode. This ARP is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances
Testing of ducted fuel injection (DFI) in a single-cylinder engine with production-like hardware previously showed that adding a duct structure increased soot emissions at the full load, rated speed operating point [1]. The authors hypothesized that the DFI flame, which travels faster than a conventional diesel combustion (CDC) flame, and has a shorter distance to travel, was being re-entrained into the on-going fuel injection around the lift-off length (LOL), thus reducing air entrainment into the on-going injection. The engine operating condition and the engine combustion chamber geometry were duplicated in a constant pressure vessel. The experimental setup used a 3D piston section combined with a glass fire deck allowing for a comparison between a CDC flame and a DFI flame via high-speed imaging. CH* imaging of the 3D piston profile view clearly confirmed the re-entrainment hypothesis presented in the previous engine work. This finding suggests that a DFI retrofit for this
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