喷雾降尘对旋式轴流风机射程的有效界定研究

为了确定喷雾降尘对旋式轴流风机的有效射程和有效界定,采用建立三维模型、建立计算流场,并分别对喷雾降尘风机进行气流单相仿真分析和气液双相耦合仿真分析的方法,得到了符合实际工况的仿真结果。通过仿真分析的对比与计算,验证仿真结果的有效性。结果表明,在标准大气压下且风机出口朝向与空气流动方向一致的条件下,出口气流速度大于1.0 m/s时就可以携带雾滴进行远程输送。这一数值模拟结果能为后续喷雾降尘风机的研究提供一定的数据参考。

煤矿区煤层气井甲烷漏失特征及漏失量模型

煤矿区煤层气开发具有良好的安全、经济和能源效益,然而地面井场甲烷漏失现象较为普遍;鉴于此,以山西沁水县煤层气排采井为研究对象,通过现场调查和多元回归分析,获取了煤层气井甲烷漏失部位和漏失量,并建立了甲烷漏失量的预测模型。结果表明:81%的煤层气井存在甲烷漏失现象,井口与排水口是甲烷漏失的2个主要部位,漏失量在0~10 m^(3)/d的井占到59%,且整体上漏失量占气井产量的1.53%;单相水流阶段几乎不存在甲烷漏失,气液两相流阶段甲烷漏失量与井底流压、冲次、日产气量呈正相关,与泵埋没度和日产水量呈负相关,其中井底流压和泵埋没度对甲烷漏失量的影响最大;在单相气流阶段,甲烷漏失量与日产气量和套管压力呈正相关,与冲次、日产水量呈负相关,其中套管压力和日产水量对甲烷漏失的影响最大。

Single Bubble Behavior in Direct Current Electric Field

The investigation on bubble behavior in electric field helps to analyze the mechanism of electric enhancement of boiling heat transfer. Experiments were performed to investigate the bubble deformation in direct current （DC） electric field with bubbles attached to the orifice. The air bubbles were slowly generated in the transformer oil pool at different orifices, so that the effect of flow on bubble shape was eliminated. The results showed that the bubbles were elongated and the departure volume decreased when the electric field was intensified. The major and minor axes, aspect ratio and departure volume increased with increasing the orifice diameter. Both the electric field and orifice size have great influence on bubble behavior. The bubble deformation was also simulated to compare with the experimental results. The numerical and experimental data qualitatively agree with each other.