• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文OA文献 >Reductions in aircraft particulate emissions due to the use of Fischer–Tropsch fuels
【2h】

Reductions in aircraft particulate emissions due to the use of Fischer–Tropsch fuels

机译：由于使用了费-托燃料，减少了飞机微粒排放

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务，本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文，但由于OA文献来源多样且变更频繁，仍可能出现获取不到、文献不完整或与标题不符等情况，如果获取不到我们将提供退款服务。请知悉。
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The use of alternative fuels for aviation is likely to increase due toconcerns over fuel security, price stability, and the sustainability of fuelsources. Concurrent reductions in particulate emissions from thesealternative fuels are expected because of changes in fuel compositionincluding reduced sulfur and aromatic content. The NASA Alternative AviationFuel Experiment (AAFEX) was conducted in January–February 2009 toinvestigate the effects of synthetic fuels on gas-phase and particulateemissions. Standard petroleum JP-8 fuel, pure synthetic fuels produced fromnatural gas and coal feedstocks using the Fischer–Tropsch (FT) process, and50% blends of both fuels were tested in the CFM-56 engines on a DC-8aircraft. To examine plume chemistry and particle evolution with time,samples were drawn from inlet probes positioned 1, 30, and 145 m downstreamof the aircraft engines. No significant alteration to engine performance wasmeasured when burning the alternative fuels. However, leaks in the aircraftfuel system were detected when operated with the pure FT fuels as a resultof the absence of aromatic compounds in the fuel.Dramatic reductions in soot emissions were measured for both the pure FTfuels (reductions in mass of 86% averaged over all powers) and blendedfuels (66%) relative to the JP-8 baseline with the largest reductions atidle conditions. At 7% power, this corresponds to a reduction from 7.6 mg kgfor JP-8 to 1.2 mg kg for the natural gas FT fuel. At fullpower, soot emissions were reduced from 103 to 24 mg kg(JP-8 and natural gas FT, respectively). The alternative fuels also producedsmaller soot (e.g., at 85% power, volume mean diameters were reduced from78 nm for JP-8 to 51 nm for the natural gas FT fuel), which may reduce theirability to act as cloud condensation nuclei (CCN). The reductions inparticulate emissions are expected for all alternative fuels with similarreductions in fuel sulfur and aromatic content regardless of the feedstock.As the plume cools downwind of the engine, nucleation-mode aerosols form.For the pure FT fuels, reductions (94% averaged over all powers) indownwind particle number emissions were similar to those measured at theexhaust plane (84%). However, the blended fuels had less of a reduction(reductions of 30–44%) than initially measured (64%). The likelyexplanation is that the reduced soot emissions in the blended fuel exhaustplume results in promotion of new particle formation microphysics, ratherthan coating on pre-existing soot particles, which is dominant in the JP-8exhaust plume. Downwind particle volume emissions were reduced for both thepure (79 and 86% reductions) and blended FT fuels (36 and 46%) due tothe large reductions in soot emissions. In addition, the alternative fuelshad reduced particulate sulfate production (near zero for FT fuels) due todecreased fuel sulfur content.To study the formation of volatile aerosols (defined as any aerosol formed asthe plume ages) in more detail, tests were performed at varying ambienttemperatures (−4 to 20 °C). At idle, particle number and volumeemissions were reduced linearly with increasing ambient temperature, withbest fit slopes corresponding to −8 × 10 particles(kg fuel) °C for particle number emissions and−10 mm (kg fuel) °C for particle volumeemissions. The temperature dependency of aerosol formation can have largeeffects on local air quality surrounding airports in cold regions.Aircraft-produced aerosols in these regions will be much larger than levelsexpected based solely on measurements made directly at the engine exit plane.The majority (90% at idle) of the volatile aerosol mass formed asnucleation-mode aerosols, with a smaller fraction as a soot coating.Conversion efficiencies of up to 2.8% were measured for the partitioningof gas-phase precursors (unburned hydrocarbons and SO) to form volatileaerosols. Highest conversion efficiencies were measured at 45% power.
机译：由于对燃料安全性，价格稳定性和燃料来源的可持续性的担忧，航空替代燃料的使用可能会增加。由于燃料成分的变化（包括减少的硫和芳烃含量），预计会同时减少这些替代燃料产生的颗粒物排放。美国宇航局替代航空燃料实验（AAFEX）于2009年1月至2月进行，旨在研究合成燃料对气相和颗粒物排放的影响。在DC-8飞机上的CFM-56发动机上测试了标准石油JP-8燃料，使用费-托（FT）工艺从天然气和煤炭原料生产的纯合成燃料以及两种燃料的50％混合气。为了检查羽流的化学性质和随时间变化的颗粒，从位于飞机发动机下游1、30和145 m处的入口探头中抽取了样品。燃烧替代燃料时，未发现发动机性能发生重大变化。但是，由于使用纯FT燃料运行时，由于燃料中不存在芳族化合物，因此检测到飞机燃油系统存在泄漏。两种纯FT燃料均实现了烟尘排放量的大幅减少（全部质量平均降低86％）功率和混合燃料（66％），相对于JP-8基准而言，减少了最大的怠工情况。在功率为7％的情况下，这对应于从JP-8的7.6 mg kg减少到天然气FT燃料的1.2 mg kg。在全功率下，烟尘排放量从103 mg kg减少到24 mg kg（分别为JP-8和天然气FT）。替代燃料还产生了更小的烟灰（例如，在功率为85％时，体积平均直径从JP-8的78 nm减少到天然气FT燃料的51 nm），这可能会降低其充当云凝结核（CCN）的能力。不管原料如何，所有替代燃料的硫和芳烃含量都有类似的减少，预计微粒排放量会减少。随着羽流冷却，发动机顺风时会形成成核模式气溶胶;对于纯FT燃料，则减少了（平均94％）所有功率的顺风粒子数排放与在排气平面处测得的相似（84％）。但是，混合燃料的减少量（减少量为30-44％）比最初测量的减少量（64％）少。可能的解释是，混合燃料废气中烟灰排放量的减少导致了新的颗粒形成微观物理的发展，而不是涂覆在已存在的烟尘颗粒上，而这在JP-8排气羽流中占主导地位。由于碳烟排放量的大幅度减少，纯净燃料（分别减少了79％和86％）和混合FT燃料（分别减少了36％和46％）的顺风粒子排放量都减少了。此外，由于燃料硫含量降低，替代燃料油降低了颗粒状硫酸盐的产生（对于FT燃料而言接近零）。为更详细地研究挥发性气溶胶的形成（定义为随着羽龄而形成的任何气溶胶），在不同的环境温度下进行了测试（−4至20°C）。闲置时，颗粒数和体积排放随着环境温度的升高而线性降低，最佳拟合斜率对应于颗粒数排放的-8×10颗粒（千克燃料）°C和颗粒体积排放的-10 mm（千克燃料）°C。气溶胶形成的温度依赖性可能会对寒冷地区机场周围的当地空气质量产生较大影响，这些地区的飞机产生的气溶胶将比仅根据直接在发动机出口平面上进行的测量所预期的水平大得多。挥发性气溶胶团块形成的成核模式气溶胶，其烟灰涂层的比例较小。对于气相前体（未燃烧的碳氢化合物和SO）的分配，形成挥发性气溶胶的转化效率高达2.8％。在45％的功率下测得的最高转换效率。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
代理获取

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号