共查询到19条相似文献,搜索用时 187 毫秒
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凹印机烘干装置风嘴横风板结构参数研究 总被引:3,自引:3,他引:0
目的研究凹印机烘干装置风嘴横风板结构参数与风场分布的关系,以提高烘干系统热风利用效率。方法通过流体力学输纸模拟计算,对比仿真计算分析不同宽度横风板风嘴的风场,选取风场的迹线图和承印物表面的压力分布为主要评估标准,分析了涡流、迹线和压力分布随横风板长度的变化规律。结果随着横风板长度的增加,涡流逐渐向承印物表面接近,迹线在承印物表面处密度增加,承印物表面整体压力略有下降,压力分布更加均匀。结论在风嘴出风口区域增加横风板有利于提高热风利用率,可使承印物表面风场分布更加均匀。为凹印机烘干风嘴结构设计及优化提供了理论依据。 相似文献
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目的为了提升包装印刷设备烘干性能,针对风嘴分布进行研究。方法依据实际包装印刷设备风嘴为参考,建立风嘴分布模型并进行非结构网格划分,根据实际情况建立适用于其工况的边界条件和控制方程;控制风嘴间距和承印物距离这2个关键参数,建立风嘴分布参数与热风场性能之间的数学模型;依据所建立数学模型估算不同参数模型的烘干效果。结果根据多组仿真实验得到了风嘴间距和承印物距离等参数对热风场分布的影响,相应经验公式为v (=-0.007×L+2.568)x~(4.311/L+0.056)。风嘴间距对于烘干风嘴影响效果明显,增加风嘴间距离可以提升烘干风嘴风速和热风场的均匀性;同时发现随着承印物不断前进和风嘴作用效果的叠加,其表面风速将持续呈现上升。结论经过研究分析,掌握了不同参数下的热风场分布规律,这对指导实际生产对于烘干风嘴设计具有重要参考价值。 相似文献
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《制冷与空调(四川)》2016,(5)
采用CFD技术对某火电厂配电间的机械通风降温效果进行了数值模拟分析,重点探讨了送风入射角度对设备散热的影响。研究结果表明,送风入射角度对室内温度场和速度场以及热源换热有较大影响。送风入射角为60°时,送风气流大部分直接流向热源区,此时速度分布较为均匀,且配电间各典型位置温度最低;综合配电间温度场、速度场和各典型位置温度分布情况,可以认为送风入射角为60°时,通风降温的效果最佳。 相似文献
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对不同形状电子元件冷却在系统中的速度场和温度场进行了模拟,建立二稳态流场及温度场模型,并运用壁面函数法进行流固边界耦合,在电子元件的散热面积为定值的条件下改变其形状,采用成熟的CFD软件进行数值求解,从而得出冷却空间二维压力场、流场及温度场分布图形。 相似文献
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为研究气相反应器空置状态配风流场特征,采用RNG k-ε湍流模型对其进行数值模拟。针对气相反应器流场的复杂性和局部多边形的特点,利用FLUENT的前处理软件GAMBIT来生成网格。对网格进行了网格无关性考核,确定了比较合理的网格数。实验结果展示了流场速度分布特征、流场湍流结构和压力场分布特征。经过对比反应器的静压分布规律数值模拟值与理论值,证实了所选的湍流模型是可靠的。本研究结果为气相反应器的设计与制造提供了参考。 相似文献
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分析水润滑动压滑动轴承的特点,并建立相关方程和边界条件,对其进行量纲一化。为精确求解紊流状态下微小润滑水膜的压力场、速度场、温度场建立数学模型,为该轴承的进一步数值计算和流场的热动力学分析奠定理论基础。 相似文献
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《Advanced Powder Technology》2020,31(1):252-268
As a new type of nozzle, the internal mixing air atomizing nozzle has been widely used in the field of dust reduction via spraying. In this study, the effect of water supply pressure on the atomization characteristics and dust-reduction efficiency of the internal mixing air atomizing nozzle was investigated. Firstly, the FLUENT software was used to simulate the flow field inside and outside the nozzle under different water supply pressures. The numerical simulation results showed that as the water supply pressure increased, the internal pressure and water flow velocity in the mixing chamber of the nozzle increased while the air flow rate decreased sharply, resulting the continuous decrease in the relative velocity between gas and liquid. Meanwhile, as the water supply pressure increased, the fragmentation scale of the liquid jet at the outlet of the nozzle was prolonged and the atomization of the liquid was limited. Secondly, based on the custom-developed dust reduction experimental system via spraying, the atomization characteristics of the nozzle were investigated. According to the experimental results, when the water supply pressure increased, the water flow rate and air flow rate of the nozzle had exponential increase and decrease, respectively. As the water supply pressure increased, the range, droplet volume fraction, droplet size, and velocity all increased, while the atomization angle first increased and then decreased. Finally, the dust reduction experiment via spraying was performed under different water supply pressures. The results showed that with the increase of water supply pressure, the dust-reduction efficiency for both the total dust and the respirable dust first increased and then decreased. 相似文献
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《Advanced Powder Technology》2023,34(5):104008
Nozzle arrangement in the nozzle spray system has a significant impact on the gas-droplet flow characteristics and the temperature distribution within the circulating fluidized bed flue gas desulphurization (CFB-FGD) tower, which is critical to the SO2 removal efficiency. The effects of spray direction, nozzle number and nozzle spray angle on gas-droplet distribution and temperature distribution inside the FGD tower are investigated with numerical simulation based on a Eulerian-Lagrangian mathematical model. An optimal nozzle arrangement scheme is proposed to improve the contact between gas and water droplets and the flue gas temperature distribution. Results show that upward spray direction is beneficial to the interaction between water droplets, improving gas-droplet flow characteristics and spray evaporation process, and water droplets number trapped by tower wall could be reduced in the water droplets evaporation. With the increase in nozzle number, it is conducive to the contact between flue gas and water droplets to increase the evaporation efficiency of water droplets, as well as the uniformity of temperature distribution inside the tower. With nozzle spray angle increases from 30° to 120°, flue gas velocity decreases, water droplets number trapped by the tower wall increases. The temperature distribution at different cross-section is the most uniform when the nozzle spray angle is 60°. 相似文献
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目的 气液双介质喷嘴的应用是烟叶加料工艺的关键因素之一,通过采用现有的模拟手段实现加料过程的高精化,为优化实验奠定基础。方法 文中以外混式双介质喷嘴为研究对象,通过构建基于DPM的数值模型,研究不同蒸汽入口压力与针阀位置对喷嘴雾化的气动性能与粒径特性的影响规律。结果 研究表明,喷嘴出口通流面积越大,气流高速区离喷嘴越近,但蒸汽与料液的速度最大值并未有较大变化,此时液滴喷射距离由远变近,喷射半角由小变大。随着蒸汽压力的增大,气流速度以及高速区长度变大,蒸汽压力为0.1 MPa时,气流速度的最大值与蒸汽压力为0.4 MPa时的相差近25%;不同压力下喷射角变化范围较小,为21.5°~23.5°;除此之外,喷雾束变集中,定向性变好,有助于控制其在烟叶表面喷射的均匀性。结论 对于较近的烟叶墙,采用较大流通截面积的喷嘴结构有利于均匀地覆盖烟叶墙,相反,对于较远的烟叶墙,则适合采用较小流通截面积的结构。适当地提高压力有利于提高料液喷洒的均匀性,减少料液的浪费,提高烟丝制备的工艺水平。 相似文献
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为解决传统三轴打印在曲面领域制备能力不足的瓶颈,克服阶梯效应等缺陷,本文设计研发了一种基于多自由度机械臂的直写式3D打印平台,并采用硅橡胶材料开展打印实验,系统研究了喷头打印角度对线条几何形状和多层线条成型效果的影响,最终制备出高保形性的结构样品。研究表明:改变喷头引导角进行打印时,随着喷头引导角度的增大,硅泡沫线条宽度的一致性更高,且引导角大于0°时所打印的线条横截面形状规则,多层结构的成型效果良好,并可改善大跨距下的线条塌陷问题。本文实验结果揭示了打印高保形性硅泡沫的多角度工艺规律,与传统的竖直方向或法线方向相比,喷头引导角大于0°时打印的硅泡沫结构保形性更高,可为曲面传感器、共形天线等对保形性要求较高的应用场合提供借鉴指导。 相似文献
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The guide vane is a common guide part in a turbo air classifier. However, there is a lack of a theoretical design basis and an analogy method is often used to design the guide vanes. The guide vanes’ effects of improving the flow field distribution are obtained by means of comparison of the flow field of the classifiers with and without guide vanes. However, the guide vane of a 15° setting angle should be optimized due to the non-uniform airflow circumferential distribution in the annular region. To obtain a well-distributed flow field of a turbo air classifier, a design method for the guide vane is provided based on the airflow trajectory in the volute and a new guide vane of a 10° setting angle is designed under the operating condition of 12–1200. The numerical simulation results show that the standard deviation of circumferential radial and tangential velocity is decreased. Besides, the trajectories of the particles with the same size in different circumferential positions show their classification results are consistent. This guide vane design method is feasible and provides the design references for the turbo air classifiers. 相似文献
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某些室内环境因空气温度高湿度大,造成外围护结构尤其是玻璃幕墙内表面结露。通过采用现场实测、理论计算和数值模拟相结合的方法对高温高湿室内围护结构表面结露进行分析,发现空调送风口与幕墙之间的距离与送风口的出风角度是主要影响因素。当风口与玻璃幕墙间距在0.2~1.1 m,出风角度在30°~45°时,基本可避免玻璃幕墙上出现大面积结露;出风角度为16°时,风口与外墙的间距越大,越有利于避免外围护结构结露;出风角度大于45°时,风口与外墙的间距越小,结露区域面积越小。 相似文献
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Recycling of waste electric and electronic equipment (WEEE) is an emerging issue due to its hazardous nature. It is important to identify an appropriate environment-friendly process to recover the valuables and for safe disposal. The present work deals with the two-stage crushing process followed by a circulating air classifier for the separation of metals and nonmetals from the printed circuit boards (PCB). The two-stage crushing process is deployed to liberate the valuables for an appropriate progeny size distribution. The metal content decreases as the particle size decreases below 0.5 mm. However, it increases metal content above 500 µm up to 1,800 µm. It is concluded that the metals primarily enriched in the size range of ?1.8 + 0.5 mm. The amount of metals and plastics present in each fraction is estimated. Among the classifier parameters, air flow velocity played a dominant role in metal enrichment. The material feed rate and rotating guide vane angle have no a significant effect on the enrichment of metals and nonmetals. The air flow velocity found was to be one of the crucial parameters for enrichment of metals. The superficial air flow velocity is optimized for efficient separation of metals and nonmetals of PCBs. 相似文献