感应式水雾荷电及其捕尘效应的研究

本文阐述感应式水雾荷电的原理及结构要素，分析了荷电雾粒的捕尘机制，并指明感应式水雾荷电除尘器提高除尘效率的技术途径。     

Combustion behaviors and explosibility of suspended metal hydride TiH2 dust

In the production and storage processes of metal hydride material of TiH₂, there are at least three kinds of explosion hazards, for example, TiH₂ dust explosion, H₂ explosion and hybrid H₂/TiH₂ dust explosion. In this study, combustion behaviors of TiH₂ dust cloud under isobaric and isochoric conditions were studied using a visual dust combustion facility and a standard 20-L spherical explosion vessel bomb, respectively, and Ti dust and hybrid H₂/Ti dust were used as the reference materials. Experimental results showed that at equal dust concentrations, the flame propagation speed S_f, burning velocity S_L, maximum pressure rise P_ex and maximum rate of pressure rise (dP/dt)_ex of TiH₂ dust were all higher than those of Ti dust, while much smaller than those of hybrid H₂/Ti dust except the maximum pressure rise P_ex. The hydrogen state and content were the primary factors for the combustion differences of dust explosions. The values of explosion index K_st showed that the explosion risks of these samples increased as follows: Ti ˂ TiH₂ ˂ hybrid H₂/Ti dust.     

反渗透滤筒对脉冲布袋除尘器清灰的影响研究

通过在滤袋内部安装特定的反渗透装置，阻碍诱导气流进入滤袋上部侧壁，减弱负压的影响，试验结果表明加入反渗透滤筒后，滤袋上部负压峰值可以降低50％，而清灰的正峰压基本没有变化，从而提高了滤袋整体的清灰能力。     

Hybrid H2/Ti dust explosion hazards during the production of metal hydride TiH2 in a closed vessel

The explosibility of hybrid H₂/Ti dust in the production of metal hydride TiH₂ was simulated and studied using a 20-L spherical vessel. The influential factors for the explosion performance of hybrid H₂/Ti dust, including particle size distribution and polydispersity, humidity, temperature, hydrogen content, inert gas and degree of reaction, on hybrid explosion were investigated. Results showed that both the mean particle sizes and particle size polydispersity had significant effects on the dust severity of hybrid H₂/Ti dust. The explosion severity of hybrid H₂/Ti dust was enhanced at a higher temperature in a certain range, and it presented a trend of increasing at the early stage and then decreased both for the increasing humidity and hydrogen pressure. Explosion inhibition effects of typical inert gases for hybrid H₂/Ti dust increased in the following order: argon < helium < nitrogen. The values of (dP/dt)_ex and V_f decreased along with the reaction process, while the value of P_ex kept stable, which showed that the hydrogen state had no obvious impact on P_ex but significantly affected the explosion risk of hybrid H₂/Ti dust, and special attention should be paid to the initial stages of the production process of TiH₂.     

微重力条件下粉尘燃烧机理研究

由落塔仓产生的微重力提供了一种独特的环境 ,可克服粉尘云在地面实验时因受重力影响而产生的沉降现象 ,使封闭容器内的整个燃烧过程能维持粉尘云的稳定悬浮 ,保证粉尘燃烧机理的实验研究中粉尘的实际浓度与初始名义浓度相符 ,令粉尘浓度名符其实地成为一个独立参变量。在 12 m落塔提供的 10 - 2 g,1.2 s微重力环境下对球形铝粉 (d50 =7μm)与球形玉米粉 (d50 =2 0μm)两种粉尘的等容燃烧特性进行了系统的实验研究。实验结果经与地面实验结果进行比较与分析后定量给出了粉尘浓度保持不变时 ,粉尘爆炸特性随扬尘湍流强度衰减而变化的规律以及在地面上重力沉降令粉尘浓度变小后对粉尘爆炸特性的影响。最后还讨论了实验容器过小而引起的部分实验数据失真的原因。     

On the investigation of photovoltaic output power reduction due to dust accumulation and weather conditions

Certain environmental conditions such as accumulation of dust and change in weather conditions affect the amount of solar radiation received by photovoltaic (PV) panel surfaces and thus have a significant effect on panel efficiency. This study conducted an experimental investigation in Surabaya, Indonesia, on the effect of these factors on output PV power reduction from the surface of a PV module. The module was exposed to outside weather conditions and connected to a measurement system developed using a rule-based model to identify different environmental conditions. The rule-based model, a clear sky solar irradiance model that included solar position, and a PV temperature model were then used to estimate the PV output power, and tests were also conducted using an ARM Cortex-M4 microcontroller STM32F407 as a standalone digital controller equipped with voltage, current, temperature, and humidity sensors to measure real time PV output power. In this system, humidity was monitored to identify dusty, cloudy, and rainy conditions. Validated test results demonstrate that the prediction error of PV power output based on the model is 3.6% compared to field measurements under clean surface conditions. The effects of dust accumulation and weather conditions on PV panel power output were then analyzed after one to four weeks of exposure. Results revealed that two weeks of dust accumulation caused a PV power output reduction of 10.8% in an average relative humidity of 52.24%. Results of the experiment under rainy conditions revealed a decrease in PV output power of more than 40% in average relative humidity of 76.32%, and a decrease in output power during cloudy conditions of more than 45% in an average relative humidity of 60.45% was observed. This study reveals that local environmental conditions, i.e., dust, rain, and partial cloud, significantly reduce PV power output.     

Numerical modelling of wind and dust patterns around a full-scale paraboloidal solar dish

This study reports on numerical predictions of velocity and pressure fields, and dust particles trajectories in steady and unsteady flows around a full-scale paraboloidal solar dish. Calculations are performed for three wind speeds of 4.16, 9.72, and 15.2 m s⁻¹, and dish pitch angles from 0° to 180°. The flow field structure, lift and drag coefficients are calculated for each flow configuration. Using the predicted mean flow velocity field, analytical expressions for the aerodynamic coefficients, as a function of the pitch angle, are developed. The unsteady-state flow is characterised by formation of stable vortices behind the dish for most flow configurations, except at 60° and 150° pitch angles. At these angles vortex-shedding occurred with a strong flow oscillation extending downstream the dish. The calculations of dust particles trajectories provide a qualitative assessment of the deposition rate, dish orientation, and surface locations where dust accumulation is most likely to occur. The study also presents an initial assessment of the effectiveness of various windbreaks installed upstream of the dish in reducing aerodynamics drag.     

移动颗粒层过滤除尘的数值模拟及实验对比

通过建立离散颗粒运动数学模型,对移动颗粒层过滤除尘器中粉尘颗粒与过滤介质颗粒碰撞以及对除尘效率的影响进行了初步研究。模拟计算了碰撞次数与系统风速之间的变化关系,与实验结果对比发现,随系统风速的变化,颗粒碰撞频次与除尘效率之间存在定性的一致。颗粒间碰撞作用对移动颗粒层的除尘性能起着重要作用。     

炼铁厂出铁口烟尘综合利用的研究

本文分析了炼铁厂出铁口烟尘的性质,并用选矿方法对烟尘进行提纯,通过重选、磁选、浮选的试验研究,结果表明;“分级一磁选”效果最好,可获得铁品位为68．78％的超级铁精矿,回收率为66．22％;另一铁精矿品位为57．93％,回收率为32．86％;尾矿铁损失率仅为0．92％。文章还对后续深加工提出了具体建议。     

Consideration of the stress dependence of the bulk density in silo storage of dusts from dry off-gas cleaning

In this study the influence of the consolidation stress on the bulk density of dusts separated from the off-gas of a broad variety of industrial processes was investigated. With the exception of very small values of the stress this dependence can be approximated very well by a simple function. One coefficient in this function correlates very well with the bulk density measured according to EN ISO 60, while the other coefficient shows a good correlation with a function, combining several dust properties. Using this approximation function equations for the vertical stress and bulk density in the shaft of a cylindrical silo as a function of the distance from the surface were derived. The results for the vertical stress and the mass of the bulk obtained with these equations were compared with those acquired on the basis of Janssen’s equation assuming constant bulk density according to EN ISO 60 and a constant average bulk density. Up to a certain distance from the surface of the bulk the values for the stress and for the mass were between the results obtained by the two variants with constant bulk density, whereas for greater distances the resulting values were higher.