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111.
循环流化床(CFB)锅炉点火系统主要以风道燃烧器为主。风道燃烧器在实际运行时,燃油着火和燃尽性能不是很理想,会出现火焰贴壁、壁面结焦等现象,因此对CFB锅炉点火系统进行数值模拟研究。针对内蒙古某电厂CFB锅炉风道燃烧器实际燃烧工况,选用非结构化有限元体积网格模型进行数值模拟。通过对点火系统的数值模拟和实测结果比较分析,验证了针对内蒙古某电厂CFB锅炉点火系统进行理论模拟所设置的物理模型和边界条件是符合实际的,理论模拟和实测结果的相对误差在10%范围内,结果较为理想。说明利用FLUENT软件对点火系统内温度场及压力场的情况进行模拟分析是可行的,对同类电厂具有一定的参考价值。 相似文献
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为了HL7 V2.x协议能够更好地应用于我国医疗信息系统(HIS)中,通过对HL7 V2.x协议的要点分析,提出了一套HL7消息解析建模解决方案.对HL7 V2.x协议的消息结构进行了分析,介绍了HL7消息解析中需要重点考虑的若干问题,给出了HL7解析应具备的操作步骤与实现过程,通过对几种典型的HL7消息解析模型方法的分析对比,提出了一套基于类结构的消息解析模型构建方法,并给出了该模型的应用原型.实验和分析结果表明了该模型的可行性. 相似文献
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Lina Su Pengfei Wang Junhui Wang Dongpeng Zhang Haitao Wang Yi Li Sihui Zhan Jinlong Gong 《Advanced functional materials》2021,31(47):2104343
Single-atom photocatalysts have shown their fascinating strengths in enhancing charge transfer dynamics; however, rationally designing coordination sites by metal doping to stabilize isolated atoms is still challenging. Here, a one-unit-cell ZnIn2S4 (ZIS) nanosheet with abundant Cu dopants serving as the suitable support to achieve a single atom Pt catalyst (Pt1/Cu–ZIS) is reported, and hence the metal single atom–metal dopant interaction at an atomic level is disclosed. Experimental results and density functional theory calculations highlight the unique stabilizing effect (Pt–Cu interaction) of single Pt atoms in Cu-doped ZIS, while apparent Pt clusters are observed in pristine ZIS. Specifically, Pt–Cu interaction provides an extra coordination site except three S sites on the surface, which induces a higher diffusion barrier and makes the single atom more stable on the surface. Apart from stabilizing Pt single atoms, Pt–Cu interaction also serves as the efficient channel to transfer electrons from Cu trap states to Pt active sites, thereby enhancing the charge separation and transfer efficiency. Remarkably, the Pt1/Cu–ZIS exhibits a superb activity, giving a photocatalytic hydrogen evolution rate of 5.02 mmol g−1 h−1, nearly 49 times higher than that of pristine ZIS. 相似文献
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《International Journal of Hydrogen Energy》2020,45(3):2360-2367
In this study, the effect of orifice geometries on the detonation propagation is considered systematically in stoichiometric 2H2–O2 mixture. Three various orifice shapes with the same blockage ratio (BR = 0.889) are used firstly, i.e., round, square and triangular. Eight PCB pressure transducers are employed to obtain the average velocity through two adjacent signals while the smoked foil technique is used to record the detonation cellular pattern. The experimental results indicate that three different propagation modes can be observed: (1) when the initial pressure (P0) is smaller than the critical value (Pc), the steady detonation wave cannot be produced before the orifice plate, afterwards, the mechanism of deflagration to detonation transition (DDT) is seen; (2) near the critical pressure, a steady detonation wave is formed prior to the obstacle, but the failure of detonation is seen after its propagation through the orifice plate due to the diffraction effect and the mass and momentum loss from the wall, and then the phenomenon of detonation re-initiation is observed due to the reflection from the wall; (3) at the initial pressure larger than the critical value, the steady detonation wave can propagate through the orifice plate without decay. Moreover, although the effect of orifice shapes on the critical pressure can be nearly ignored, the re-ignition position is different among three various orifice geometries. For the cases of round and square orifices, the ignition position is produced near the center of the wall. However, the detonation wave is re-ignited from the corner in the case of triangular orifice. Finally, the critical condition of detonation propagation can be quantified as DH/λ > 1. But the critical values of DH/λ are not uniform among three different orifice geometries. For the cases of round, square and triangular orifices, the critical values of DH/λ are 8.94, 5.88 and 3.84, respectively. 相似文献
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