共查询到19条相似文献,搜索用时 140 毫秒
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毛绘宇 《制冷空调与电力机械》2010,31(2):107-109
简单介绍了气力垃圾输送管道的种类和材料。重点介绍了几种不同材质和工艺的钢管及其适用范围,并对其进行了比较,指出了螺旋焊管和直缝焊管各自的特点和优势;详细阐述了埋地气力输送钢管的土壤腐蚀类型及比较常见的防腐方法,重点介绍了目前已在气力输送工程中实际应用的3PE防腐、环氧涂层防腐和阴极保护防腐的工艺流程和特点;最后提出了气力垃圾输送管道应用中存在的一些问题和展望。 相似文献
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分析了炭黑在气力输送过程中的破碎机理。通过实验,介绍了气力输送系统中炭黑的种类和炭黑的物性对炭黑的破碎的影响,指出气力输送系统的输送管路长度和布置以及输送参数如输送压力和输送速度等的变化直接影响着炭黑的破碎率的大小。为更好地解决炭黑在气力输送中存在的问题,优化炭黑气力输送系统的设计提供了依据。 相似文献
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分析了炭黑在气力输送过程中的破碎机理.通过实验.介绍了气力输送系统中炭黑的种类和炭黑的物性对炭黑的破碎的影响.指出气力输送系统的输送管路长度和布置以及输送参数如输送压力和输送速度等的变化直接影响着炭黑的破碎率的大小.为更好地解决炭黑在气力输送中存在的问题,优化炭黑气力输送系统的设计提供了依据. 相似文献
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密相气力输送系统中几种气量控制方式的比较 总被引:1,自引:0,他引:1
从调压范围、压力特性和流量特性方面介绍了减压阀的主要性能,讨论了气力输送交流中减压阀的选择和调节,分析了密相气力输送系统中各种气量控制方法,对其各自的优缺点进行了详细讨论,重点分析减压阀及减压阀与拉法尔联合气量控制系统的优、缺点,表明可调式拉法尔管是今后气力输送气量控制发展的方向。 相似文献
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Hui Li 《Particulate Science and Technology》2000,18(3):187-198
In order to prevent flow blockage phenomenon and to reduce the impact of particles on the wall of the bend, an experimental study of the swirling flow pneumatic conveying system with a horizontal curved pipe was carried out in this work. The experiment was performed in a 90-deg pipe bend with pipe diameter 75 mm and centerline curvature ratio 12. The straight pipes with 75 mm inside diameter at the upstream and downstream of the bend were 1.3 m and 4.0 m in lengths, respectively. The initial swirl number was varied from 0.22 to 0.60, the mean air velocity from 10 to 20 m/s, and the solid mass flow rate from 0.07 to 0.68 kg/s. It is found that in the lower air velocity range, the overall pressure drop of the swirling flow pneumatic conveying shows a lower tendency than that of axial flow pneumatic conveying. The minimum air velocities can be decreased by using the swirling flow pneumatic conveying. From the visualization of particle flow patterns, the impact of particles on the wall of the bend can be reduced using the swirling flow. 相似文献
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HUI LI 《Particulate Science and Technology》2013,31(3):187-198
ABSTRACT In order to prevent flow blockage phenomenon and to reduce the impact of particles on the wall of the bend, an experimental study of the swirling flow pneumatic conveying system with a horizontal curved pipe was carried out in this work. The experiment was performed in a 90-deg pipe bend with pipe diameter 75 mm and centerline curvature ratio 12. The straight pipes with 75 mm inside diameter at the upstream and downstream of the bend were 1.3 m and 4.0 m in lengths, respectively. The initial swirl number was varied from 0.22 to 0.60, the mean air velocity from 10 to 20 m/s, and the solid mass flow rate from 0.07 to 0.68 kg/s. It is found that in the lower air velocity range, the overall pressure drop of the swirling flow pneumatic conveying shows a lower tendency than that of axial flow pneumatic conveying. The minimum air velocities can be decreased by using the swirling flow pneumatic conveying. From the visualization of particle flow patterns, the impact of particles on the wall of the bend can be reduced using the swirling flow. 相似文献
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Analysis of Gas-Solids Feeding and Slug Formation in Low-Velocity Pneumatic Conveying 总被引:1,自引:0,他引:1
J. Li S. S. Pandiella C. Webb T. Dyakowski M. G. Jones 《Particulate Science and Technology》2003,21(1):57-73
Gas and solids feeding is a key operation in pneumatic conveying of particulate materials. This article presents an analysis of the interfacing effects between a nozzle gas supplier, a rotary valve solids feeder with dropout box, and the pipeline of a pneumatic conveying test rig for low-velocity dense-phase flow. Experiments were carried out to examine the flow pattern of slugs in different combinations of gas flow conditions and solids loading ratios. The effect of gas and solids feeding on the formation of slugs is analyzed by using both experimental data and computer-modeled results. Solids accumulation and sliding motion at the bottom of the dropout box and near the entrance of the downstream pipe, which happen prior to the bulk motion in the form of a slug, are found important in determining the size of a slug. Gas retention and pressure buildup characteristics in the feed section are also found crucial in influencing the flow patterns of slugs. 相似文献
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ABSTRACTA horizontal dilute-phase pneumatic conveying system using vertically oscillating soft fins at the inlet of the gas–particle mixture was studied to reduce the power consumption and conveying velocity in the conveying process. The effect of different fin lengths on horizontal pneumatic conveying was studied in terms of the pressure drop, conveying velocity, power consumption, particle velocity, and intensity of particle fluctuation velocity for the case of a low solid mass flow rate. The conveying pipeline consisted of a horizontal smooth acrylic tube with an inner diameter of 80 mm and a length of approximately 5 m. Two types of polyethylene particles with diameters of 2.3 and 3.3 mm were used as conveying materials. The superficial air velocity was varied from 10 to 17 m/s, and the solid mass flow rates were 0.25 and 0.20 kg/s. Compared with conventional pneumatic conveying, the pressure drop, MPD (minimum pressure drop), critical velocities, and power consumption can be reduced by using soft fins in a lower air velocity range, and the efficiency of fins becomes more evident when increasing the length of fins or touching particles stream by the long fins. The maximum reduction rates of the MPD velocity and power consumption when using soft fins are approximately 15% and 26%, respectively. The magnitude of the vertical particle velocity for different lengths of fins is clearly lower than that of the vertical particle velocity for a non-fin conveying system near the bottom of the pipeline, indicating that the particles are easily suspended. The intensities of particle fluctuation velocity of using fins are larger than that of non-fin. The high particle fluctuation energy implies that particles are easily suspended and are easily conveyed and accelerated. 相似文献
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The pneumatic system is frequently operated in the high air velocity region, which aggravates the power consumption and erosion of bend, and the intensive study of the particles motion characteristic on a horizontal-vertical pneumatic conveying in various curved 90° bends is necessary. This experimental study focuses on the particles motion characteristic of bend on the horizontal-vertical pneumatic conveying with oscillatory flow (generated by installing the oscillator) in terms of on pressure drop, powder consumption, the evolution of particle velocity and particle fluctuating intensity during flowing through bends. The results indicate that powder consumption can be reduced by using oscillatory flow, which is more obvious with a larger radius ratios bend. Meanwhile, the pressure drop proportion of bend is higher than average pressure drop of the system within the same distance. Otherwise, the total reduction particles velocity through bend is less while using oscillatory flow, which is more obvious using larger radius ratios bend. The particle velocity using oscillatory flow is higher than that of the conventional pneumatic conveying for the cases of larger radius ratios bend, and this effect is less evident while through a smaller radius bend. 相似文献
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《Advanced Powder Technology》2020,31(6):2285-2292
To reduce the power consumption of a horizontal-vertical pneumatic conveying system, an oscillator is mounted with a 45° oblique plane through the pipe axis in this study. This experimental study focuses on the effect of oscillatory flow using the oscillator on the horizontal-vertical pneumatic conveying system in terms of the overall pressure drop of the system, power consumption, local pressure drop, and particle velocity. Compared with conventional pneumatic conveying (axial-flow), the pressure drop and power consumption can be reduced using the oscillatory flow in a lower air velocity range. Meanwhile, the particle axial velocity of the oscillatory flow is higher than that of the axial-flow near the bottom of pipe. This outcome indicates that the accelerating effect of oscillatory flow is obvious near the bottom of the pipe, and the particle vertical velocity of the oscillatory flow is positive, whereas the particle vertical velocity of the axial-flow is almost negative. This result shows that the particles of the oscillatory flow are suspended sufficiently, but the particles of the axial-flow have a tendency of deposition. Furthermore, the fluctuation intensity of the particle velocity of the oscillatory flow is higher than that of the axial-flow, especially near the bottom of the pipe. 相似文献
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The minimum transport or capacity limitation boundary for low-velocity slug-flow pneumatic conveying affects the design and operation of conveying systems. Unfortunately, the relevant mechanisms involved with this boundary still lack full understanding and assessment. Investigations have been carried out to model the capacity limitation for the low-velocity slug-flow pneumatic conveying of poly granules through horizontal pipes. Pipeline diameter, air mass flow rate, and operating pressure have been found to affect the maximum slugging capacity of this material. A semiempirical equation has been established to predict the maximum solids mass flow rate for a given air mass flow rate and conveying pipeline. Good agreement has been achieved between the model predictions and the experimental results over a wide range of airflows and pressures. 相似文献