<粗体>背景和目的:粗体>鼻气道阻塞(NAO)的原因很多,但鼻中隔偏曲是最常见的病因。鼻中隔偏曲会影响鼻腔内的气流动力学,进而影响鼻腔的加热、加湿、过滤等生理功能。本研究调查并比较了健康鼻腔与鼻中隔偏曲鼻腔的气流模式。
<粗体>方法:粗体>本研究考虑并比较了两种鼻道导气管模型。一个有鼻中隔偏曲另一个鼻腔完好气流分析是通过使用Materialise MIMICS (Materialise, Ann Arbor, MI)将CT扫描发展成3D模型,然后使用ANSYS 2020R2的FLUENT求解器进行的。采用SST k-ω湍流模型对层流和湍流进行了模拟。采用多面体网格,采用网格收敛指数法进行网格检验。
<粗体>结果:粗体>在大范围的质量流量下评估压力和速度分布。结果表明,当质量流率超过15 LPM时,湍流流动模式。在鼻中隔偏曲的鼻腔中,速度曲线显示了异常的流动曲线,其中峰值速度在鼻中区域而不是鼻瓣区域观察到。 There was a 38% to 55% higher nasal resistance in the septal deviated nasal cavity as compared to a normal and healthy nasal cavity. The pressure drop in the septal deviated nasal cavity is higher by 60%–120% when compared to a healthy nasal cavity.
镍(Ni),铝(Al)和钛(Ti)的金属间化合物体系是提供耐高温的轻质材料的候选材料。燃烧合成是利用燃烧释放的热量产生金属间化合物和涂层沉积的一种广泛研究方法。通常使用底层来增强涂层对基材的附着力。因此,涂层和衬底层在加热过程中的相互作用对于获得良好的附着质量至关重要。本工作旨在研究燃烧合成形成的NiAl涂层和Ti衬底之间界面形成的微观结构和性能。采用感应加热启动加热和反应过程,加热速率分别为46.6、57.0和85.5 K/s。采用带有能谱仪的扫描电子显微镜(SEM)对其微观结构进行了表征,而采用x射线衍射(XRD)测试对其形成相进行了表征。用维氏显微硬度试验测定了其硬度分布。结果表明:涂层区形成了富al和富ni的NiAl;当升温速率分别为46.6、57.0和85.5 K/s时,涂层的平均厚度分别增加了约200、300和400 μ m。 The different thicknesses of the coating can be attributed to the migration of Ni/Al from the coating to the underlayer zones. The microstructure observed in the underlayer confirms the formation of several intermetallic phases of Ni-Ti and Ti-Al systems. The infiltration of Ni and Al elements from Ni and Al to Ti sides was responsible for generating a reaction between Ni-Ai-Ti. The formation of Ti2Ni–Ti3Al phases in the underlayer increases with the heating rate. The hardness across the coating, interface, and underlayer increases with the heating rates. The heating rate of 46.6, 57.0, and 85.5 K/s results in the hardness of the interface by 669.1, 804.8, and 967.7 HV, whereas the underlayer increases by 680.1, 772.7, and 978.7 HV, respectively. The increased content of the Ni-Al-Ti system, which are AlNi2Ti and Ti2Ni–Ti3Al phases, was attributed to the increased hardness of the interface and underlayer. This work improves the understanding of second reactions across the interface while fabricating coatings that apply an underlayer.