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微尺度下氢氧预混合气催化燃烧的研究 总被引:1,自引:0,他引:1
基于空间气相和表面催化的详细化学反应机理,应用计算流体动力学软件对亚毫米燃烧器内的氧氧预混合燃烧进行模拟,在对催化燃烧模型进行试验验证的基础上,讨论不同反应模型的燃烧特性以及壁面材料和进口流速等对催化燃烧反应的影响.模拟结果显示,表面催化反应会使壁面相邻位置空间气体内的OH质量分数降低,对该催化壁面临近区域的气相反应有所抑制;壁面催化反应与空间气相反应耦合进行时,燃烧效率可达到最大值;进口速度对出口排气温度的影响要大于对外壁面最高温度的影响,进口速度过高会导致燃烧效率降低;燃烧器材料的选择也对催化燃烧有着重要的影响,采用热导率较小的材料时,燃烧器壁面存在较高的温度梯度,燃烧器外壁面温度也较高,而采用热导率较大的材料时,壁面对进口端的气体预热作用增强,高温燃烧区域向入口端移动. 相似文献
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随着天线工作频段的扩展以及实际应用的需求,越来越多的科研单位投入了对毫米波甚至到亚毫米波天线的开发,毫米波亚毫米波天线测量系统也成为了研发过程中不可或缺的设备,本文将主要针对测试频率高于40GHz 的系统,从暗室系统的建设、系统机械扫描架的建设、RF 子系统的搭建、系统综合测试性能的评测以及实际建设的系统方面来
对毫米波亚毫米波系统的建设提供参考性意见,以期为需要建设类似系统的科研单位提供理论和实际的工程参考。 相似文献
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Bing Gong Guowei Lou Xingguo Li 《Journal of Infrared, Millimeter and Terahertz Waves》2009,30(11):1234-1242
In the sub-millimeter wave propagation process, attenuation is mainly due to the effects of atmospheric particles, such as
water vapor. It’s also caused by absorption and scattering by hydrometeors. This paper focuses on the effects of hydrometeors
on sub-millimeter wave propagation. The formula for calculating the attenuation cross-section of raindrops is given, as well
as the distance formula of sub-millimeter wave radiometers. Finally, this paper mentions the effects of some weather phenomena
on detection distance of sub-millimeter wave radiometers. Taking cloud attenuation as an example, the relation between distance
and temperature or moisture content is analyzed. 相似文献
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Toshio Suzuki Yoshihiro Funahashi Toshiaki Yamaguchi Yoshinobu Fujishiro Masanobu Awano 《Journal of power sources》2008,183(2):68
Fabrication and characterization of tubular SOFCs under sub-millimeter (0.8 mm), bundles and stacks for low temperature operation were shown. The materials used in this study were Gd doped CeO2 (GDC) for electrolyte, NiO–GDC for anode and (La, Sr)(Co, Fe)O3 (LSCF)–GDC for cathode, respectively, and LSCF for supports of the tubular cells for bundle fabrication. After applying a sealing layer and current collector for each bundle of five micro tubular SOFCs, each bundle was stacked vertically, to build a four-storey cube-type stack with volume of about 0.8 cm3. The performance of the stack was shown to be 3.6 V OCV and 2 W maximum output power under 500 °C operating temperature. Preliminary quick start-up test was also conducted at the condition of 3 min start-up time from 150 to 400 °C for 5 times, and the results showed no degradation of the performance during the test. 相似文献
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