共查询到20条相似文献，搜索用时 156 毫秒
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本文论述了湍流和次流影响粒子的传递速度,降低了静电除尘器的效率,并在Navie—stokes和Shaug hnessy方程的基础上,进一步推导了气速理论的方程式,这一方程包括了在除尘器流体场中的电晕放电的影响。同时指出电极设计应使其能发射预计的总电流量,以使气流、湍流对静电除尘器的收集效率干扰最小。 相似文献
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本文研究了离子风对空间电场的影响。采用静电探针法分析了不同线板配置下的空间电流值，并对不同电场区域的离子风进行了讨论。研究表明，在不同的电压等级下存在一种最优的极配方式，对静电除尘器的优化设计有着重要的参考价值。 相似文献
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《赤峰学院学报(自然科学版)》2016,(15)
采用混合模拟法研究地球远磁尾磁场重联过程,分析了离子温度的特性及其在出流区的动力学问题.磁场重联过程使离子温度在等离子体片边界层中显著升高的同时,在重联边界层过渡区表现出了十分明显的T‖T⊥的温度各向异性,而激波的上游区温度情况却与之相反.速度分布的模拟结果显示,出流区离子速度分布随着磁场重联的发展和演化逐渐偏离了初始的麦克斯韦分布,出现部分球壳状的分布.重联进一步演化之后,离子在速度空间分离成两部分,形成类哑铃状分布位形. 相似文献
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在电解过程中,不同的阴阳离子在通电时,电极放电的先后顺序是不同的。溶液中同时存在多种离子时,它们在电解时将按一定的顺序进行放电。 相似文献
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用惰性电极电解电解质溶液时所用到的电解原理,常让学生感到学习困难,不易理解,难以掌握和运用.在教学实践中,我通过研究分析,发现突破口在于对离子放电规律的理解和应用上,并引入教学中,教学效果良好.现总结如下,希望能对学习者有所帮助.
一、离子在惰性电极上的放电规律
在惰性电极上,发生电极反应的离子与其放电难易程度有关,一般的,越容易放电的离子,越容易发生电极反应. 相似文献
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给出了不同电极数目下电磁流量计权重函数的仿真结果.权函数表示流动横截面上特定空间位置上的流体速度对流量计输出信号的相对作用.权函数的求解对根据电磁流量计测量的电位差来推断速度分布是很重要的.通过对比不同数目电极下权重函数的分布,可以得出,电极数目越多,对流型的敏感度越小,从而可以实现对非轴对称流流量准确的测量. 相似文献
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梁海东 《四川职业技术学院学报》2000,(3)
电解池中的电极是电源确定的．和外电源正极相连的电极是阳极，在电解过程中阳极将电子送回到电源；和外电源的负极相连的电极是阴极，阴极有供电解液中的阳离子获得的多余电子．通电后，电解液中的阴离子向阳极运动，阳离子向阴极运动．其能否在两极放电，主要由离子的放电顺序和电极材料决定． 放电顺序： 若用金属（Ａｎ、Ｐｔ除外）作阳极，则金属先失电子． 根据以上情况，现将用惰性电极电解酸、碱、盐的水溶液时，溶液酸碱性和ｐＨ的变化分析归纳如下：１阳极若发生 ４ＯＨ－ ４ｅ＝ ２Ｈ２Ｏ＋ Ｏ２＋，则由于 ＯＨ一放电使水的电离… 相似文献
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为研究离心式分离腔体内部气流流动轨迹以及梗丝颗粒的运动规律,进一步深入研究梗丝分离效果,基于ANSYS建立流体域模型,利用流体仿真软件Fluent,采用RNG湍流模型模拟腔体内气流轨迹,拉格朗日离散相模型（DPM）模拟颗粒相运动规律,得到腔体内气流轨迹、压力和颗粒相运动轨迹云图,并在入口处设定不同大小的气流速度,当入射速度为6m/s时,气流流动轨迹发生改变,达到8m/s时气流轨迹比较理想,且颗粒运动轨迹正确。此时梗丝在离心分离腔体内可以得到有效分离,梗中含丝率降低到2.55%左右,烟丝利用率进一步提高。 相似文献
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邱玉英邱琳祯 《福建工程学院学报》2021,(1):84-88
以小型数据服务机房为研究对象,对机房使用列间空调后的气流组织进行了分析。利用CFD(流体动力学)软件对房间内的气体流动情况进行模拟,绘制温度、矢量风速计算云图,对比了冷通道封闭前后房间温度场、风场的变化,分析封闭前后室内换热情况。研究发现,冷通道封闭后离地0.5、1.5m处平均温度较封闭前平均温度下降2℃左右,机柜顶面下降1℃左右。封闭冷通道能够优化气流组织,有效避免气流短路,机房内局部热点消失,无效换热减少。 相似文献
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为了研究空芯光纤中氩气的放电特性,利用有限元软件 COMSOL Mutiphysics 基于流体模型对长为50mm 空芯光纤中的气体放电过程进行仿真,得到氩气放电过程中等离子体的主要参数分布,如电子密度、离子密度、电势、空间电荷密度、电场强度等。同时分析了气压对放电过程的影响,结果表明,气压对气体放电的影响主要体现在电子密度与阴极侧的电场强度上,随着气压的逐渐增大,阴极侧的电场强度也随之增加,阴极侧电子密度则保持不变,但在空芯光纤中央区域,电子密度的增大较为明显。 相似文献
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To provide physically based wind modelling for wind erosion research at regional scale, a 3D computational fluid dynamics
(CFD) wind model was developed. The model was programmed in C language based on the Navier-Stokes equations, and it is freely
available as open source. Integrated with the spatial analysis and modelling tool (SAMT), the wind model has convenient input
preparation and powerful output visualization. To validate the wind model, a series of experiments was conducted in a wind
tunnel. A blocking inflow experiment was designed to test the performance of the model on simulation of basic fluid processes.
A round obstacle experiment was designed to check if the model could simulate the influences of the obstacle on wind field.
Results show that measured and simulated wind fields have high correlations, and the wind model can simulate both the basic
processes of the wind and the influences of the obstacle on the wind field. These results show the high reliability of the
wind model. A digital elevation model (DEM) of an area (3800 m long and 1700 m wide) in the Xilingele grassland in Inner Mongolia
(autonomous region, China) was applied to the model, and a 3D wind field has been successfully generated. The clear implementation
of the model and the adequate validation by wind tunnel experiments laid a solid foundation for the prediction and assessment
of wind erosion at regional scale. 相似文献
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为了研究锂离子电池充（放）电过程中热性能特点,更好地进行热管理分析,基于 Fluent 软件建立锂离子电池组三维瞬态散热模型并对温度场进行仿真计算,分析不同条件对电池及模组散热性能的影响。结果表明：减小充（放）电倍率和增大表面对流换热系数可改善电池因温度过高而导致的热失控。进口风速从 0.5 m/s增至 6 m/s 且 4C 充电终止时,电池组最高温度、平均温度、温差、一致性系数降低了 33.57 K、21.23 K、9.84 K 和 2.82%,但泵功耗增加了 0.35 W。进风温度从 298.15 K 降至 283.15 K 且 4C 充电终止时,电池组最高、平均温度降低 12.8 K 和 13.92 K,温差与一致性系数升高 1.86 K 和 0.76%。即增大风速,电池组温升和温度均匀性得到改善;降低进风温度,可控制电池组温升,但温度均匀性抑制效果变差。 相似文献
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The low temperature plume exhausted from a cryogenic wind tunnel may sink down, posing a severe threat to public health and safety. Quantitative risk assessment of cryogenic plume flow behavior therefore plays an important role in the design and optimization of a cryogenic wind tunnel. A numerical model with a modified Hertz-Knudsen relation considering the phase change physics of the small quantity of water involved is applied to analyze the dispersion of the low temperature nitrogen plume exhausted from a 0.3 m cryogenic wind tunnel. The homogeneous multiphase flow is modeled using the single-fluid mixture model. A model validation is presented for the exhaust plume from the US National Transonic Facility (NTF). The predicted results are found to be better than those predicted by National Aeronautics and Space Administration (NASA)’s two-stage analytical model. The influences of the environmental wind speed, the environmental wind temperature, the relative humidity, and the exhaust flow rate, on low temperature nitrogen plume dispersion are obtained. In particular, the parametric sensitivities of different influence factors are analyzed. The environmental wind temperature and the exhaust flow rate of the nitrogen gas have greater impact on the temperature of the plume near the ground than do the environmental wind speed and the relative humidity. The exhaust flow rate of the nitrogen gas has greater impact on the oxygen concentration near the ground than does the environmental wind speed, while the environmental wind temperature and the relative humidity have negligible impacts. The results provide guidance on the operation and design improvement of a cryogenic gaseous nitrogen discharge system to avoid its potential hazards. 相似文献
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基于暖体假人的低温灾害模拟实验系统设计 总被引：1，自引：0，他引：1
开发了一套利用制冷系统实现最低-18℃低温环境,在其中以暖体假人为核心实验设备的低温灾害模拟实验系统.系统使用压缩机组采用风冷实现降温,并利用微控制器实现系统控制和温度的自动调节;系统使用先进的暖体假人模拟人体发热、发汗等生理活动,配置多点环境温湿度器在线测量室内环境变化.经测试,此实验系统降温速度约1℃/min,同时墙体保温性能以及制冷送风最大风速符合低温环境研究的基本要求.这一低温灾害模拟系统的建立,可为开展围绕低温灾害中人体生理反应的相关研究提供实验条件,为低温环境中防护装备的有效性及舒适性等研究提供有效支撑. 相似文献
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The construction of a building may change the microclimate in the vicinity, and planning indicators in a master plan may directly affect the outdoor physical environmental quality in residential areas. An inappropriate plan for a site may accelerate wind and intensify vortexes over places on the pedestrian levels, which leads to an adverse outdoor environment. Therefore, the design of a cluster of buildings should not focus only on the buildings but also provide a good outdoor environment around the buildings. To tackle the problem of inadequate wind environment, the relationship between the building’s floor area ratio and height was identified in this study as the main planning indicator to be examined on its effects on the outdoor wind environment. A computational fluid dynamics (CFD) model was hence developed to simulate the wind conditions generated by some typical site layouts with different values for planning indicators under relevant weather conditions, which were typical of those in Hangzhou, China. The simulated wind conditions are assessed using the wind speed ratio over the whole area of the building cluster at the pedestrian level. The effects on the local wind condition due to the varying of the planning indicators are discussed whilst considering the potential construction costs. The indicators resulting in better external conditions are highlighted in the conclusion as the recommendation which could be used as a rule of thumb by architects and planners at the master planning stage. The study disproves the common belief in the practice that a lower floor area ratio means fewer buildings and therefore greater external comfort. In fact, the higher the building, the greater the outdoor comfort wind zone for pedestrians. However, the increment in comfort area is limited to buildings extending from 25 to 30 levels. 相似文献