This paper describes a computational fluid dynamic method used for modelling changes in aircraft geometry due to icing. While an aircraft undergoes icing, the accumulated ice results in a geometric alteration of the aerodynamic surfaces. In computational simulations for icing, it is necessary that the corresponding geometric change is taken into consideration. The method used, herein, for the representation of the geometric change due to icing is a non-cut cell Immersed Boundary Method (IBM). Computational cells that are in a body fitted grid of a clean aerodynamic geometry that are inside a predicted ice formation are identified. An IBM is then used to change these cells from being active computational cells to having properties of viscous solid bodies. This method has been implemented in the NASA developed node centered, finite volume computational fluid dynamics code, FUN3D. The presented capability is tested for two-dimensional airfoils including a clean airfoil, an iced airfoil, and an airfoil in harmonic pitching motion about its quarter chord. For these simulations velocity contours, pressure distributions, coefficients of lift, coefficients of drag, and coefficients of pitching moment about the airfoil's quarter chord are computed and used for comparison against experimental results, a higher order panel method code with viscous effects, XFOIL, and the results from FUN3D's original solution process. The results of the IBM simulations show that the accuracy of the IBM compares satisfactorily with the experimental results, XFOIL results, and the results from FUN3D's original solution process.

关键词：空气动力系数；空气阻力；边界；计算流体动力学

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This project was designed to address the Solar Energy Technology Program objective, to develop new methods to integrate photovoltaic (PV) cells or modules within a building-integrated photovoltaic (BIPV) application that will result in lower installed cost as well as higher efficiencies of the encapsulated/embedded PV module. The technology assessment and development focused on the evaluation and identification of manufacturing technologies and equipment capable of producing such low-cost, high-efficiency, flexible BIPV solar cells on single-ply roofing membranes.

关键词：太阳能电池；膜；建筑；建材

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Proton exchange membrane fuel cells (PEMFCs) are being developed and sold commercially for multiple near term markets. Ballard Power Systems is focused on the near term markets of backup power, distributed generation, materials handling, and buses. Significant advances have been made in cost and durability of fuel cell products. Improved tolerance to a wide range of system operation and environmental noises will enable increased viability across a broad range of applications. In order to apply the most effective membrane electrode assembly (MEA) design for each market, the system requirements and associated MEA failures must be well understood. The failure modes associated with the electrodes and membrane degradation are discussed with respect to associated system operation and mitigating approaches. A few key system considerations that influence MEA design include expected fuel quality, balance-of-plant materials, time under idle or open circuit operation, and start-up and shut-down conditions.

关键词：燃料电池；膜；电极；耐用性

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In an effort to understand and quantify the carbon and sulfur contents of a curium oxide production process performed in the hot cells at Oak Ridge National Laboratory's Radiochemical Engineering Development Center, a non-radioactive surrogate was used in a similar oxide formation process. Neodymium (Nd), which was chosen as a substitute for curium, was loaded onto a Dowex 50W-X8 resin by use of ion exchange column techniques and then treated under a variety of processing conditions. The surrogate product was analyzed for carbon and sulfur impurities, using inductively coupled plasma-mass spectrometry for sulfur assessment, a LECO combustion furnace/analyzer for carbon quantification, and X-ray diffraction for compound identification. The results indicate that the carbon and sulfur contents in the Nd oxide were similar to current estimations for curium oxide using the reference hot cell process. It was also seen that the major surrogate product of the hot cell process contained sulfur in a Nd oxysulfate (Nd2O2SO4) compound. Parametric analysis of the resin decomposition process revealed that increasing the temperature to 1400 degrees C yielded considerably better removal of carbon and sulfur.

关键词：钕；树脂；碳； Curicum氧化；分解；热电池

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Numerical simulation capabilities to perform flowfield analysis and sensitivity analysis of solid oxide fuel cells (SOFCs) have been developed. A three-dimensional, implicit, multi-species fuel cell solver is modified to analyze cell geometries supplied by NexTech Materials (NexTech). Four different NexTech cell configurations of varying complexities have been analyzed in this study. A capability to perform thermo-mechanical analysis of NexTech cells is developed by coupling the fuel cell code with the structures code. The capability was initially developed for a simplified cell that also included sensitivity analysis of thermo-mechanical variables. Sensitivity derivatives are computed using the direct differentiation method in the fuel cell and structures codes.

关键词：燃料电池；氧化物；平面结构；耦合（互动）

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Heat transfer of phase change material (PCM) in an open cell micro- foam structure was numerically studied. A high constant temperature was specified at the top surface of the structure. Each unit of the micro-foam is a body-centered-cubic (BCC) lattice embedded with spherical micro-pores. Two different simulation methodologies were applied. One is the high-fidelity direct numerical simulation (DNS), which allows for the effective thermo- physical parameters to be derived. The other methodology is a volume-averaged simulation based on one- and two-temperature models. Our results show that the volume-averaged simulation can accurately and efficiently capture the phase change process in PCM/micro-foam systems, with the effective thermal conductivity derived from direct simulations and expressed as a power law of porosity.

关键词：储电池；储能材料；热转化

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This report documents the demonstration of a self-adhering, thin-film photovoltaic (PV) technology applied to a new aluminum-zinc coated standing-seam metal roof (SSMR) with a high-performance coating. The demonstration took place at Kilauea Military Camp (KMC), HI, which has a uniquely corrosive environment due to the periodic presence of volcanic gases. It also has high electric utility costs and limited grid capacity. The corrosion performance of the roof and PV solar array was evaluated by periodic visual examination, onsite atmospheric coupon testing, and accelerated weathering laboratory tests of material coupons. Sensors were also installed at the interface between the PV membrane and roofing material, mounted in outdoor exposure at the site, to record any developing signs of corrosion. Af-ter a year in service, the PV appliqu modules were found to have no deleterious effect on the new SSMR, and the PV system performed as expected. However, due to the high first-costs related to procuring the thin-film PV components, the 30 year return on investment (ROI) ratio was only 0.19. Although the system is not economical enough to warrant Army-wide implementation, it may be specified in individual cases where energy sustainability is a higher priority than ROI.

关键词：光伏发电系统；太阳能；能量转换

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As a first step towards a microscopic understanding of single-Pt atom-dispersed catalysts on non-conventional TiN supports, we present density- functional theory (DFT) calculations to investigate the adsorption properties of Pt atoms on the pristine TiN(100) surface, as well as the dominant influence of surface defects on the thermodynamic stability of platinized TiN. Optimized atomic geometries, energetics, and analysis of the electronic structure of the Pt/TiN system are reported for various surface coverages of Pt. We find that atomic Pt does not bind preferably to the clean TiN surface, but under typical PEM fuel cell operating conditions, i.e. strongly oxidizing conditions, TiN surface vacancies play a crucial role in anchoring the Pt atom for its catalytic function. Whilst considering the energetic stability of the Pt/TiN structures under varying N conditions, embedding Pt at the surface N-vacancy site is found to be the most favorable under N-lean conditions. Thus, the system of embedding Pt at the surface N-vacancy site on TiN(100) surface could be a promising catalyst for PEM fuel cells.

关键词：吸附原子；燃料；缺陷（材料）

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This presentation summarizes the results of NREL's analysis of hydrogen fuel cell performance in the key early markets of material handling equipment (MHE) and backup power.

关键词：备用电源；储能；燃料电池；氢能

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Under direct impact from ballistic loads, acoustic waves typically propagate throughout a structural component causing damage to sensitive areas. For structures with intelligent embedded monitoring systems, such as mounted piezoelectric actuators, a direct impact between 150 200 m/s of small-caliber rounds has produced catastrophic results. This report focuses on redirecting acoustic waves using non-traditional structural configurations. The technical approach utilizes periodic and graded metamaterials (produced from auxetic cellular, lattice topology and material composition), which are lightweight and can be assembled for extreme anisotropy and phononic bandgaps, which can be exploited to alter the propagation path of high amplitude stress waves. This research focuses on the initial stage of understanding how to tailor periodic lattices for highly concentrated impact and blast loads, which generally produce a broadband frequency response and yield only partial bandgaps. Specific attention is given to square, hexagonal, re-entrant, and modified re- entrant topologies. As a baseline comparison, a solid aluminum plate is examined against uniform and graded re-entrant unit cell lattices. The plates are individually subjected to both in- and out-of-plane direct impact loading conditions of a 0.22-caliber fragment simulating projectile traveling at 300 m/s. A less than 10% marginal difference in peak stress amplitude exists between the loading conditions for a given single through-the-thickness unit cell.

关键词：声波；弹道；结构组件；执行器；爆炸荷载

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