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81.
Xiaojun Gao Tao Cui Zongyan Zhou Yingbo Yu Yang Xu Dongxing Zhang Wei Song 《Advanced Powder Technology》2021,32(5):1438-1449
This paper presents a numerical study on the motions of seed particles in a novel high-speed seed metering device based on the discrete element method. The effects of key parameters, including inlet velocity of particles, feeding rates and the angle of seed cleaning element, are investigated by a series of controlled numerical experiments. The results show that in the seed filling area of the device, a better match of particle velocity and the tangential linear velocity of the seeding plate can improve the seed filling performance. The number of particles remaining in the metering device is an important factor that affects the device performance. A large number of particles in the device results in more multiple seeding, and a small number causes more leakage seeding. Under the conditions of the seeding plate rotational speed at 194.5 rpm (corresponding to the high ground speed of 14 km/h), feeding rate at ~14 seeds/s can ensure that around 24 seed particles are maintained in the device which generates minimum leakage and multiple seeding. The studies of the effect of the seed cleaning element angle show that an appropriate angle (e.g., 30°) can effectively enhance the clearing ability, increase the uniform stability of particles backflow, and improve the seeding performance. 相似文献
82.
This study aims to examine the practicality of a novel passive heat transport system “thermosyphon heat transport device” (THTD). It is a fluid-filled unit, with both source and sink amalgamated within it. A vertical tube-in-tube design has been incorporated, consisting of heat source, adiabatic height, and sink. To showcase the performance, a transient numerical analysis is performed using ANSYS Fluent, which is compared with the simple closed thermosiphon (SCT) for heat transport capability (1 kW) and different adiabatic heights (0.25, 1, and 1.5 m). Also, the influence of axial conduction is examined. The proposed Therminol VP1-based THTD has better heat transport capability over SCT due to a uniform flow pattern. Although the time response diminishes with adiabatic height, the novelty is justified as the heat gained by THTD (adiabatic height: 1.5 m) is 1.5 times more than SCT. Furthermore, the THTD performance is experimentally analyzed by varying the coolant flow rate (0.01, 0.02, and 0.03 kg/s), heat load (100−600 W), and transport distance (0.25 and 0.75 m), which yielded 80%−90% energy efficiency. As the THTD is crucial for a conceptual solar indoor cooker, the response under transient heating/cooling conditions is also investigated, which depicted 300 s for transient heating and 10−50 s for transient cooling. 相似文献
83.
84.
《International Journal of Hydrogen Energy》2022,47(57):24242-24253
As hydrogen refueling stations become increasingly common, it is clear that a high level of economic efficiency and safety is crucial to promoting their use. One way to reduce costs is to use a simple orifice instead of an excess flow valve, which Japanese safety regulations have identified as a safety device. However, there is concern about its effect on refueling time and on risk due to hydrogen leakage. To clarify the effect, we did a study of model-based refueling time evaluation and quantitative risk assessment for a typical refueling station. This study showed that an orifice is an effective alternative safety device. The increase in refueling time was less than 10%, based on simulations using a dynamic physical model of the station. Neither was there a significant difference in the risk between a configuration with excess flow valves and one with an orifice. 相似文献
85.
针对阴极剥片机组核心区域剥片装置故障高的问题 , 结合生产操作 , 以及实际检修过程 , 从设备的角度分析剥片装置故障率高的主要原因 , 根据原因提出设备改进方案 , 降低剥片装置故障率,保证剥片机组稳定运行,并且通过改进检修方式,减少故障检修时间,降低检修劳动强度。 相似文献
86.
Investigation on the miniaturized parallel multichannel-based devices packed with glass beads to improve the mass exchange execution is the critical focal point of the current study. One of the essential parameters to specify the miniaturized devices' flow distribution is the residence time distribution (RTD). In the present context, the RTDs of a liquid tracer were investigated for the air-water multiphase flows (concurrent) across the multichannel-based miniaturized devices (comprising of 11 similar dimensional parallel channels). The devices were variable in height and packed with glass beads. The conductivity estimations generated the RTD curves and were addressed by the axial dispersion model (ADM). The fluid-flow rates differed within the range of 5–23 ml min−1. The axial dispersion coefficients and the rate of the specific energy dispersion were investigated. The effects of pressure difference and geometry on the hydrodynamic attributes and mixing properties were well-illustrated, and the new correlations were suggested. 相似文献
87.
88.
围绕斜巷运输的特点,针对斜巷上车场容易发生跑车事故的状况,设计制作了一种基于气动的、能自动连锁形式的挡车器,消除了斜巷运输的安全隐患,最终实现斜巷防跑车的自动化控制,对类似条件下的斜巷运输的安全管理提供了可借鉴的经验。 相似文献
89.
厂用电源的快速切换技术近年来在大型发电机组厂用电系统中运用日臻完善和成熟,显示出它对确保机组稳定运行的优越性,并已在生产实际中积累了丰富的运行经验。分析了平顶山某电厂应用的2种快速切换装置的原理和使用中出现的问题及解决方法,提出了解决的思路。 相似文献
90.
煤矿自动控制风门的选择与应用 总被引:4,自引:1,他引:4
通过对目前煤矿使用的自动控制风门的原理进行分析,指出各种自动控制风门的优缺点及在使用选择过程中的注意事项,并重点介绍了PLC控制器在煤矿自动控制风门设计中的重要性。 相似文献