Results 1 - 10 of 11
Results 1 - 10 of 11. Search took: 0.017 seconds
|Sort by: date | relevance|
[en] In 1994, Ford produced a small demonstration fleet of Mercury Sables with aluminum bodies. Argonne National Laboratory obtained one of these vehicles on a lease so that Laboratory staff could observe the wear characteristics of the body under normal operating conditions. The vehicle was placed in the transportation pool, parked outdoors, and used by staff members for both local and longer trips. The vehicle performed normally, except for having particularly good acceleration because of its light weight and highpower SHO engine. No significant problems were encountered that related to the Al body or engine. No special driving protocols were observed, but a log was kept of trip lengths and fuel purchases. Fuel economy was observed to be improved, compared with that of a similar conventional steel-bodied vehicle that was available for one year of the lease period. The vehicle was tested on a chassis dynamometer to obtain emissions and fuel economy over the federal test cycle. The impacts of further mass reduction were also simulated. At the end of the lease, the body was in excellent condition, which we documented with a set of detailed photographs before the vehicle was returned to Ford. There were minor imperfections in the painted surface, probably resulting from the omission of an E-coat during the painting process. We also examined three similar conventional vehicles for comparison; these exhibited varying degrees of rust
[en] A quantitative and time-resolved radiographic technique has been used to characterize hollow-cone gasoline sprays in the near-nozzle region. The highly penetrative nature of x-rays promises the direct measurements of dense sprays that are difficult to study by visible-light based techniques. Time-resolved x-radiography measurement enables us to map the mass distribution near the spray nozzle, even immediately adjacent to the orifice. The quantitative nature of the measurement also permits the re-construction of spray structure and the progress of the spray development. It is observed that the speed of fuel injected in the later part of the injection is higher than injected earlier and that the initial fuel speed variation caused the spray plume to be compressed in space
[en] Traditionally, anaerobic digestion has been used for the reduction of volatile suspended solids and mass of concentrated sludge produced in Waste Water Treatment Plants (WWTPs). In recent years, anaerobic biological treatment has been widely introduced due to biogas production and low energy cost. Furthermore, it has been extended to waste water treatment and other waste streams (e.g. agriculture and livestock waste) as different configurations such as Upflow Anaerobic Sludge Blanket (UASB) or Anaerobic Membrane Bioreactor (AnMBR). Nevertheless, there are some important factors to control in anaerobic treatment such as temperature, pH and inhibitory compounds so that the operation of these processes are not as robust as Conventional Activated Sludge (CAS).
[en] In this paper, the energy savings of new technology offering significant improvements in fuel efficiency are tracked for over 20 years as vehicles incorporating that technology enter the fleet and replace conventional light-duty vehicles. Two separate analyses are discussed: a life-cycle analysis of aluminum-intensive vehicles and a fuel-cycle analysis of the energy and greenhouse gas emissions of double vs. triple fuel-economy vehicles. In both efforts, market-penetration modeling is used to simulate the rate at which new technology enters the new fleet, and stock-adjustment modeling is used to capture the inertia in turnover of new and existing current-technology vehicles. Together, these two effects--slowed market penetration and delayed vehicle replacement--increase the time lag between market introduction and the achievement of substantial energy savings. In both cases, 15-20 years elapse, before savings approach these levels
[en] Air-water two-phase flow is present in natural and industrial processes of different nature as nuclear reactors. An accurate local prediction of the boiling flow could support safety and operation analyses of nuclear reactors. An Eulerian-Lagrangian approach is investigated in this contribution as it can be used as a virtual facility to investigate the two-phase flow phenomena. A solver based on the PISO algorithm coupled with the Lagrangian equation of motion have been implemented for computing incompressible bubbly flows. (Author)
[en] Significant experimental work and modeling about vertical T-junction as a phase separator has been done for churn and annular flows, but a survey on the literature reveals a lack of experimental data regarding bubbly flow nor any phenomenological explanation to their behavior. The objective of this work is to extend the understanding of these junctions by obtaining complete datasets, i.e. of both gas and liquid, of the phase splitting process in bubbly flow conditions by means of conductivity needle probes, Laser Doppler anemometry and visual inspection. Measurements and observations of the phase split, as well as the vortex structure in a vertical T-junction with equal pipe diameters (52 mm inner diameter), are reported. Results suggest a relationship between the vortex structure and the efficiency of the junction as phase separator.
[en] With the popularity of light trucks increasing in the United States, their share of the US light vehicle market had doubled between 1980 and 1996, climbing from 20 to 40%. By 1996, annual energy consumption for light trucks had risen to 5.97 x 1015 Btu [5.97 quadrillion Btu, or ''quad'', or 6.30 x 1018 joule (J)], compared to 7.94 quad (8.38 x 1018 J) for cars. In recent years (since 1995), the fuel economy of US-manufactured light trucks (almost 99% of which use gasoline engines) has been below the Corporate Average Fuel Economy (CAFE) standards. This paper analyzes a strategy to reduce the CAFE shortfalls by adopting the new, highly energy-efficient clean diesel engine. Research on such engines has been funded by the US Department of Energy, Office of Heavy Vehicle Technologies, under its Light Truck Clean Diesel Engine Program. A clean diesel engine market penetration trajectory is developed, representing an industry response to meet the CAFE standards. Whether the engine will be produced inside the country or imported remains uncertain, so two cases are defined. Values of exports/imports of clean diesel engines/trucks under these cases are estimated. The macroeconomic benefits are estimated by using a model of the US economy developed by Standard and Poor's Data Resources, Inc. On the basis of gains in the gross domestic product projected under the alternative cases, domestic production of the clean diesel engine is favored over importing it. (author)
[en] Water based nanofluids of SiO2 and Al2O3 were characterized regarding its later use in heat transfer applications. Well dispersed nanofluids were prepared at three different volume fractions (0.5% v., 1% v., 5% v.) and for each one the experimental measurements were carried out at three different temperatures (40°C, 60°C, 80°C). Commercial nanofluids acquired in liquid state were compared with nanofluids prepared by dispersing dry powder in water. The thermal conductivity, the viscosity and the specific heat of all the prepared nanofluids were measured in order to calculate the Mouromtseff number and establish the optimal conditions. Finally, the stability of the nanofluids was also studied through the evolution of the amount of light scattered by the sample during a period of time.
[en] Despite its variable degree of application, intrusive instrumentation is the most accurate way to obtain local information in a two-phase flow system, especially local interfacial velocity and local interfacial area parameters. In this way, multi-needle probes, based on conductivity or optical principles, have been extensively used in the past few decades by many researchers in two-phase flow investigations. Moreover, the signal processing methods used to obtain the time-averaged two-phase flow parameters in this type of sensor have been thoroughly discussed and validated by many experiments. The objective of the present study is to develop a miniaturized multi-needle probe, based on capacitance measurements applicable to a wide range of non-conductive two-phase flows and, thus, to extend the applicability of multi-needle sensor whilst also maintaining a signal processing methodology provided in the literature for conductivity probes. Results from the experiments performed assess the applicability of the proposed sensor measurement principle and signal processing method for the bubbly flow regime. These results also provide an insight into the sensor application for more complex two-phase flow regimes. (paper)