受老空水威胁工作面巷道防治水实践

针对高庄煤矿3_上1104回风巷为沿空掘巷,巷道掘进期间受3_上1102老空水威胁,掘进开采存在严重的水患安全问题,采用超前打设疏水孔的方案来治理老空水威胁,对巷道采用调向增大护巷煤柱厚度等措施实现巷道安全快速掘进,探放水期间无淹巷情况发生,探放水后巷道顶板和上帮无淋水现象发生。     

Experimental investigation on the invert stability of operating railway tunnels with different drainage systems using 3D printing technology

In recent years, the invert anomalies of operating railway tunnels in water-rich areas occur frequently, which greatly affect the transportation capacity of the railway lines. Tunnel drainage system is a crucial factor to ensure the invert stability by regulating the external water pressure (EWP). By means of a three-dimensional (3D) printing model, this paper experimentally investigates the deformation behavior of the invert for the tunnels with the traditional drainage system (TDS) widely used in China and its optimized drainage system (ODS) with bottom drainage function. Six test groups with a total of 110 test conditions were designed to consider the design factors and environmental factors in engineering practice, including layout of the drainage system, blockage of the drainage system and groundwater level fluctuation. It was found that there are significant differences in the water discharge, EWP and invert stability for the tunnels with the two drainage systems. Even with a dense arrangement of the external blind tubes, TDS was still difficult to eliminate the excessive EWP below the invert, which is the main cause for the invert instability. Blockage of drainage system further increased the invert uplift and aggravated the track irregularity, especially when the blockage degree is more than 50%. However, ODS can prevent these invert anomalies by reasonably controlling the EWP at tunnel bottom. Even when the groundwater level reached 60 m and the blind tubes were fully blocked, the invert stability can still be maintained and the railway track experienced a settlement of only 1.8 mm. Meanwhile, the on-site monitoring under several rainstorms further showed that the average EWP of the invert was controlled within 84 kPa, while the maximum settlement of the track slab was only 0.92 mm, which also was in good agreement with the results of model test.     

An experimental study of forced convective heat transfer for fully developed Al 2 O 3 –water nanofluid in an annulus tube

Nanofluids have been known as practical materials to ameliorate heat transfer within diverse industrial systems. The current work presents an empirical study on forced convection effects of Al₂O₃–water nanofluid within an annulus tube. A laminar flow regime has been considered to perform the experiment in high Reynolds number range using several concentrations of nanofluid. Also, the boundary conditions include a constant uniform heat flux applied on the outer shell and an adiabatic condition to the inner tube. Nanofluid particle is visualized with transmission electron microscopy to figure out the nanofluid particles. Additionally, the pressure drop is obtained by measuring the inlet and outlet pressure with respect to the ambient condition. The experimental results showed that adding nanoparticles to the base fluid will increase the heat transfer coefficient (HTC) and average Nusselt number. In addition, by increasing viscosity effects at maximum Reynolds number of 1140 and increasing nanofluid concentration from 1% to 4% (maximum performance at 4%), HTC increases by 18%.     

城市排水管网风险评估研究

总结了常见的城市排水管网风险评估的方法及软件,对污水管网的气体爆炸风险、雨水管网的内涝风险、综合风险这三类风险评估的文献进行了归纳整理,并对未来的研究重点及趋势做出了预测。     

现代市政道路给排水管道工程的设计与施工探讨

市政道路给排水管道工程设计与施工是一个综合性的过程,要考虑各个方面的影响因素,其工程质量关系着城市运行的稳定性,具有非同寻常的作用。在市政道路给排水工程施工中,需要涉及到多个工艺环节,要合理调控各个环节的连接关系,保证工程的有序施工,严格管控工程质量。     

井下通风、排水及压缩空气设备选型设计

依据井下通风方式及瓦斯含量对井下通风设备进行了选型设计,给出了进行反风时的通风机工作特性以及通风机的电控形式;对井下排水设备和压缩空气设备进行了选型设计。井下工程实践表明,所选用的设备可满足矿井的正常生产需要。     

瓦斯抽采集成旁通阀二位放水器研制

针对井下瓦斯抽采中原放水器配气阀安装不规范、双截止阀使用繁琐、工人劳动强度大等现状,研制了具有集成调控装置的放水器,能够实现一个阀门控制所有气路和水路,自主放水和负压排水,从源头上杜绝了瓦斯喷孔和水流溢出等情况,大大降低了职工的劳动强度,实现了井下抽采系统安全可靠运行。     

热仿真技术在加固显示器热设计中的应用

根据某型加固显示器的应用环境及内部功能模块的热特性,选择强迫风冷的散热方式,并通过热仿真计算指导风扇选型,根据仿真结果验证散热方案的可行性。最终,依据试验结果验证仿真结果的准确性,为加固显示器的热设计提供思路。     

恒温恒湿调节箱内气流分布状态及其对卷烟调节效果的影响

  目的  了解恒温恒湿调节箱内的气流分布，验证不同规格卷烟样品在调节箱内的调节效果。  方法  改变在恒温恒湿调节箱内卷烟样品的数量、堆积方式和摆放位置，使用热敏风速仪检测调节箱内特征点的强制气流速度；使用ISO 3402标准规定的平衡判定方法，对不同规格的卷烟调节效果进行了验证。  结果  （1）行业常用的卷烟恒温恒湿调节箱内气流分布并不均匀，各个位置气流速度差异较大，某些位置甚至无法检测到强制气流；（2）卷烟在恒温恒湿调节箱的调节过程中，改变样品数量、堆积方式和摆放位置时，对箱体内各位置的气流强度有一定影响，影响效果并无明显规律，且对箱内整体气流分布均匀度没有明显影响；（3）当调节时间满足48 h时，烟支规格对卷烟调节至平衡并无影响，卷烟样品均能达到标准规定的平衡要求，3 h内重量变化不大于0.2%的判定方法符合国内卷烟调节的实际情况。  结论  该研究结果对生产企业以及实验室研究人员在使用卷烟恒温恒湿调节箱和卷烟样品平衡的验证都具有一定的指导意义。      

采场动压分布特征及高效瓦斯抽放技术研究

河南地区大部分煤矿所采煤层均属于三软煤层，煤层透气性差，瓦斯治理困难。现阶段河南区域煤与瓦斯突出矿井主要采用穿层钻孔及开采保护层作为区域防突措施，而低瓦斯矿井或临突矿井（低瓦斯矿井与煤与瓦斯突出矿井相邻）存在高瓦斯区时，仅仅用风排瓦斯很难达到治理效果，近些年煤矿发生瓦斯事故多数为低瓦斯矿井，所以低瓦斯矿井和临突矿井存在高瓦斯区域的工作面回采期间瓦斯治理尤为重要。根据采场“竖三带”和“横三区”理论，利用钻孔抽放效果考察法和工作突出预测指标法研究了采场围岩动压分布特征。在此基础上，通过优化动压区抽放钻孔设计，提高了瓦斯抽放效果。瓦斯抽放量提高了1.8倍，有效降低了工作面生产期间的风排瓦斯量，提高了生产效率，保证了矿井安全生产。