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蓄冷技术的发展引起了空调系统的重大变革,低温送风空调也日益受到了人们的关注。文中利用fluent6.3,通过对低温送风空调系统室内气流组织进行模拟分析,研究室内的温度、气流速度、空气流动规律及ADPI。 相似文献
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超音速脱水分离是基于气体动力学和传热传质理论提出的-种新型天然气脱水净化分离技术。该技术采用超音速分离管,使多组分的高压天然气膨胀、提速、旋转,降温,其中的水蒸气及可凝组分发生相变成为液相并被分离出来。旋流器是超音速分离管中决定天然气脱水性能的关键部件,其在分离管内的位置会对管内流场产生重要的影响。本文借助CFD软件(FLUENT)模拟分离管内的高速流动,对比四种不同旋流器位置的超音速分离管流动过程中温度、压力和速度的变化,通过分析数值结果可以得出在相同的压损比下采用旋流后置-Ⅰ型超音速分离管可以获得更大的温降。 相似文献
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《低温与超导》2016,(6)
明确激波在Laval喷管内的发生位置,能够为设计及优化Laval喷管线型提供理论依据,从而提高Laval喷管的制冷性能和整个天然气超音速分离器的分离效率。文中对Laval喷管进行了结构设计,对不同背压条件下Laval喷管内激波位置进行了理论分析与计算,并利用FLUENT软件进行了数值模拟,通过研究不同背压条件下Laval喷管内气体马赫数、压力和温度分布,对喷管制冷性能进行了对比分析。结果表明:保持Laval喷管入口压力不变,随出口背压增大,激波位置逐渐从喷管出口向喷管入口方向移动,气体受到激波的影响,在喷管所能达到的最大马赫数不断降低,所能产生的最低温度不断上升,喷管的制冷性能越差;理论计算与数值模拟结果基本一致,数值模拟验证了理论计算的正确性。 相似文献
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The present study was designed to assess the effect of head position on glottic closure as reflected in airflow rates (open quotient and maximum flow declination rate), in patients with unilateral vocal fold paralysis. Ten patients, 2 males and 8 females ranging in age from 40 to 75, with a mean age of 57.3, served as subjects. Airflow measures were taken during sustained phonation of two vowels (/i/ and /a/) in 3 head positions (center, right, left). Vowels /i/ and /a/ were produced at subject's comfortable pitch and loudness, with random ordering of both vowel order and head orientation. Subjects were trained to focus eye gaze on right and left markers (70-degree angle) and a central marker at eye level directly in front of the subject. Theoretically, if turning the head during phonation alters the laryngeal anatomic relationship by bringing the vocal folds in closer proximity to one another, then airflow rate should lessen. Our results indicate that head position does not improve glottic closure in these patients, which is in contrast to previously published research.(1) Our results question the utility and underlying theoretical construct for the use of head turning as a therapeutic technique for improvement of voice in patients with unilateral vocal fold paralysis. 相似文献
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冷藏运输车内气体流场的数值模拟及分析 总被引:2,自引:0,他引:2
利用计算流体力学(ANSYS)软件,建立了冷藏运输模拟试验台的物理模型,对冷藏运输车内流场进行了数值模拟研究。主要研究内容包括:(1)不同送风速度对冷藏运输车内流场分布的影响;(2)不同时间内库内流场变化情况。冷藏运输模拟试验台采用前端送风,两侧回风口的送风方式。风机吹出的冷气能够在库体内形成大的回流,从而降低库体温度并且使库体内温度分布的均匀。不同送风速度影响车体内速度场的分布,而当送风速度较大时,库内的温度会在短期内均匀。但是过大的送风速度会风干冷藏车内的食品。 相似文献
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为了验证模型的正确性,针对一种平行流蒸发器,建立了3D和2D计算模型。并采用fluent软件和3D耦合传热计算模型,分析了迎面风速变化时空气侧的主要结构参数(翅片间距、翅片厚度、百叶窗间距和百叶窗角度)对空气侧传热系数和压降的影响规律。 相似文献
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A prototype RPC with position resolution less than 1 mm has been produced and studied. Based on this RPC detector, the effect of the width of the integrated FADC time window on the position resolution of a RPC has been studied experimentally and theoretically. The results of theoretical calculation and experimental measurement have shown good agreement. 相似文献
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光镊利用光学梯度力捕获和操控微小粒子,已经成为深入研究生物分子间相互作用等微观机制的独特技术.光镊光束操控系统一般由扩束输入镜、扩束输出镜、调焦透镜、耦合透镜和压电转镜等光学元器件组成,以保证物镜后瞳充满的前提下实现光镊阱位操控.光镊阱位的三维精确操控是实现光镊位钳和力钳模式的基本条件.本文根据矩阵光学,对基于无穷远校正显微镜的光镊操控光路进行计算,分析扩束输入镜、调焦透镜和物镜轴向位置调整,以及压电转镜、调焦透镜和耦合透镜安装位置误差对光镊径向阱位操控精度的影响,得到了物镜高度调整基本不会影响光镊径向位置操控,压电转镜和调焦透镜的安装位置误差对光镊径向阱位操控精度影响最大等结论,提出了能够实现径向阱位精确操控的轴向阱位动态操控范围,为光镊设计和操控提供理论和实验指导. 相似文献
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A prototype RPC with position resolution less than 1 mm has been produced and studied. Based on this RPC detector, the effect of the width of the integrated FADC time window on the position resolution of a RPC has been studied experimentally and theoretically. The results of theoretical calculation and experimental measurement have shown good agreement. 相似文献
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Peijue Xun Qingyuan Wang Fan Wang Shanfu Yu Shenggang Liu 《International Journal of Infrared and Millimeter Waves》1990,11(12):1385-1394
The dispersion characteristics of the dominant mode in shielded microstrip lines on magnetized ferrite and anisotropic dielectric substrates have been obtained. The solution is obtained by applying the transverse equivalent transmission line in the spectral domain and Galerkin's method. Numerical results for the frequency-dependent propagation constants are presented which could be used in designing directional couplers and isolators. 相似文献
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This paper addresses optimization of a high-speed digital feedback controller for a plasma position in Damavand tokamak. Damavand
tokamak discharges have plasma currents up to 40 kA with discharge duration greater than 15 ms and toroidal magnetic fields
up to 1.2 T. The plasma position is measured using saddle-loops and Rogowski coil and is controlled by electromagnetic forces
generated by passing currents through control coils placed around the plasma. A desired control objective is maintaining the
plasma in the center of vacuum vessel and to stabilize the plasma in the presence of disturbances in a time domain of the
order of few milliseconds. In order to achieve maximum performance it is essential to optimize the control system. In this
paper plasma position measurement and the details of implementing high-speed PID controllers based on a TMS320c25 digital
signal processor along with the system optimization are presented. 相似文献