Effects of Sparger Holes on Gas-Liquid Hydrodynamics in Bubble Columns

A multiphase second-order moment turbulent model was developed including an improved closure Reynolds stress transport to describe effectively the anisotropic characteristics of bubble-liquid turbulent flow. The two-phase hydrodynamics in a bubble column were numerically simulated by an in-house code. The effect of the amount of jetting holes on bubble-liquid hydrodynamics in relationship with a cell culture was investigated. Firstly, the bubble energy production correlation was proposed to verify the higher cell damage rate near gas inlet regions. The larger amounts of jetting holes resulted in an increase of bubble stress, bubble kinetic energy, and energy dissipation, particularly bubble energy production at the near gas inlet, which boosted cell damage.     

Cold start optimization of the proton-exchange membrane fuel cell by penetrating holes in the cathode micro-diffusion layer

Enhancing the cold start ability of proton-exchange membrane fuel cells (PEMFCs) can widely apply fuel cells in a cold environment. In this study, PEMFC cold start performance was significantly affected by penetrating holes in a cathode micro-diffusion layer (MDL). The testing MDLs were mechanically processed with 0.2-mm-diameter and 0.5-mm-diameter penetrating holes, respectively, and the normal MDL as reference. Fundamental water permeance and PEMFC performance tests at normal temperature were conducted beforehand for all MDLs. The cold start of the fuel cell was experimentally studied by monitoring PEMFC voltage and high-frequency impedance. Results show that the 0.5-mm-diameter penetrating holes improve the water permeance at least three orders of magnitude than the normal MDL. The fuel cell using the MDL with the 0.2-mm-diameter penetrating holes performs best in regular operation at 70 °C and in cold starts from ?7 °C.     

隧洞开挖典型掏槽设计方法

针对目前隧洞开挖爆破施工中缺少具体、详细的掏槽设计方法的现状,提出了最常用的2种典型掏槽方式,并详细论述了其设计方法。这些掏槽方式及设计方法均在实际施工中得到了推广应用,并且取得了良好的爆破效果。实际应用表明:这些典型掏槽方式及设计方法能有效提高硬质岩石开挖的钻孔利用率,能将钻孔利用率提高到98%～100%,实现掌子面基本无残孔,从而有效提高单循环进尺,加快开挖进度,降低开挖成本。     

10710工作面灰岩探查孔出现问题分析

针对10710工作面机巷施工灰岩探查孔过程中出现的问题,从底板岩层应力分布状态方面分析,寻找钻孔变形的原因,提出防治措施,避免类似事故发生。     

采掘工作面煤壁浅孔动压注水在治理瓦斯中的应用

朱庄煤矿结合该矿机械化程度较高的有利条件，利用现有综采机组的液压系统，试验采用煤壁浅孔动压注水治理瓦斯，有效地解决了常规方法利用边采（掘）边抽治理瓦斯的设备和专业认伍投入等一系列问题，取得了良好的经济和社会效益。     

综采工作面收作期间工作面内防火技术

介绍了综采工作面收作期间工作面内的一种防火技术途径,给出了钻场位置的选择和钻孔的施工方法,并对防火效果进行了分析。     

平造立浇在盘类零件上的应用

分析煤矿 1 0 0 0mm带式输送机连接减速机和带式输送机联轴器中圆盘铸件产生缩孔、缩松的原因。采用平造立浇铸造工艺 ,消除了铸件中的缩孔、缩松等缺陷 ,生产出合格的铸钢圆盘铸件     

高位钻孔抽放瓦斯技术在新安煤矿的应用

采用高位钻孔抽放煤层顶板裂隙带瓦斯，不断改进、合理确定钻孔的布置方式和参数，提高抽放效果，有效地控制工作面的瓦斯涌出与回风流中的瓦斯浓度，保障了工作面的安全生产。     

脆性材料有效爆破范围的试验研究

针对无底柱分段崩落法爆破中出现的问题，采用脆性材料对井下矿扇形炮孔爆破进行相似材料的模拟试验，试验揭示了扇形爆破的方向性与顺势破坏效应，可以指导矿山爆破优化设计，提高爆破能利用率，降低矿石贫化率。     

液压油缸的修复工艺

分析了液压油缸密封件损坏的原因。确定了对液压油缸缸体腐蚀、磨损的修复方案。对普通车床进行改造以完成对缸体的镗孔、滚压工序,提高缸体内表面的加工精度,减少了密封件的损坏,延长了液压油缸的使用寿命。