Power density

About: Power density is a research topic. Over the lifetime, 9534 publications have been published within this topic receiving 197264 citations. The topic is also known as: volumic power & volume power density.

High Power Density Silicon Combustion Systems for Micro Gas Turbine Engines

Abstract: As part of an effort to develop a micro-scale gas turbine engine for power generation and micro-propulsion applications, this paper presents the design, fabrication, experimental testing, and modeling of the combustion system. Two radial inflow combustor designs were examined; a single-zone arrangement and a primary and dilution-zone configuration. Both combustors were micro-machined from silicon using Deep Reactive Ion Etching (DRIE) and aligned fusion wafer bonding. Hydrogen-air and hydrocarbon-air combustion was stabilized in both devices, each with chamber volumes of 191 mm3 . Exit gas temperatures as high as 1800 K and power densities in excess of 1100 MW/m3 were achieved. For the same equivalence ratio and overall efficiency, the dual-zone combustor reached power densities nearly double that of the single-zone design. Because diagnostics in micro-scale devices are often highly intrusive, numerical simulations were used to gain insight into the fluid and combustion physics. Unlike large-scale combustors, the performance of the micro-combustors was found to be more severely limited by heat transfer and chemical kinetics constraints. Important design trades are identified and recommendations for micro-combustor design are presented.Copyright © 2002 by ASME

Largely enhanced discharge energy density in linear polymer nanocomposites by designing a sandwich structure

Abstract: The development of flexible film dielectric capacitors with high discharge energy densities is of central significance for advanced electric and electronic power systems. Herein, a novel sandwich structure designed barium titanate/poly(methyl methacrylate) (BT/PMMA) nanocomposites are prepared layer-by-layer using solution casting method. The outer two layers with low BT nanoparticles concentration offered a considerably higher breakdown strength, while the central polarization layer with higher BT nanoparticles concentration presented higher dielectric constant to the nanocomposites. Consequently, 1-9-1 BT/PMMA nanocomposite compared to its single-layered counterpart (i.e. 9 wt% BT/PMMA) showed a ∼238% improvement in discharge energy density (i.e. from 1.8 J/cm3 to 6.08 J/cm3). The discharge rate analysis presented that 1-9-1 BT/PMMA discharges in 2.44 μs with a power density of about 0.5 MW/cm3 at a time constant (τ0.9). This work significantly paves the way for using sandwich-structured linear polymer nanocomposites in high energy density and fast discharge rate dielectrics application.

Estimation of the average power density in the vicinity of cellular base-station collinear array antennas

Abstract: This paper investigates the character of the average power density in the close proximity of base-station antennas, where human exposure to electromagnetic fields radiated from such radiofrequency (RF) sources is the highest. The concept of average power density is used since, in proximity of a large array antenna, the direction of the power flow at a given point is not readily predictable because of the substantially diverging path lengths and direction of propagation of the energy arriving from different array elements. This quantity Is shown to have a marked cylindrical decay near the antennas, which converts to spherical in the far field. On this basis, a set of simple prediction formulas is derived to allow the estimation of the average power density with good precision. The latest IEEE C95.1-1999 Standard for RF safety calls for spatially averaged measurements of incident power density to verify compliance to maximum permissible exposure limits. The advantage of using the concept of average power density and the resulting prediction formulas is that the evaluation of the exposure of humans near cellular base-station antennas becomes extremely simple during surveys when large computerized scanning equipment may not be available.

A Design Optimization Tool for Maximizing the Power Density of 3-Phase DC–AC Converters Using Silicon Carbide (SiC) Devices

Abstract: The emergence of wide-bandgap devices, eg, silicon carbide (SiC), has the potential to enable very high-density power converter design with high-switching frequency operation capability A comprehensive design tool with a holistic design approach is critical to maximize the overall system power density, eg, by identifying the optimal switching frequency This paper presents a system level design tool that optimizes the power density (volume or mass) of a three-phase, two-level dc–ac converter The design tool optimizes the selection of the devices, heatsink and passive components (including the design of the line, electromagnetic interference (EMI), and dc-link filters) to maximize the power density The structure of the optimization algorithm has been organized to reduce the number of potential design combinations by over 99%, and thus, produces fast simulation times The design tool predicts that when SiC devices are used instead of Si ones, the power density is increased by 1594% A 5 kW, 600-V dc-link, three-phase, two-level dc–ac converter was experimentally evaluated in order to confirm the accuracy of the design tool