Abstract:

With the global energy scarcity, the exploration of process energy conservation method is of great significance. The fire prevention plays an important role in the national economy and social development. If the techniques of drag-reduction by additives being applied into the firefighting system, the jet velocity and range of firefighting water can be increased, consequently, the firefighting efficiency will be improved and the power consumption of fire pumps will be reduced. According to the characteristics of fire water flow, the polymer of polyethylene oxide (PEO) and surfactant of octadearyl dimethyl ammonium chloride (OTAC) are chosen to be mixed as the drag-reduction additives for the firefighting system. The method of mesoscopic molecular dynamics simulation is utilized in the present study to calculate the shear resistance and surface tension of the PEO/OTAC mixed solution. The results show that the PEO/OTAC mixed solution has higher shear resistance capacity than the PEO or the OTAC solution, and higher surface tension than the OTAC solution under the same conditions, i.e., concentration, temperature, and so on. It proves that the PEO/OTAC mixture is suitable for the firefighting system as the drag-reduction additives. Meanwhile, the interaction mechanism of PEO and OTAC molecules is analyzed from the perspective of molecular dynamics deeply, which can provide theory instruction for further research of the suitable drag-reduction additives for the firefighting system.

Key words: firefighting flow drag-reduction, polymer and surfactant mixed solution, mesoscale, molecular simulation, interfacial tension

摘要：

在全球能源紧张的背景下，“过程节能”手段的探索具有重要意义。消防工作在国民经济和社会发展中占据重要地位，将添加剂湍流减阻技术引进到消防系统，能提高消防水的射出速度和射程，在提高灭火效率的同时节省水泵功耗。根据消防水流特点，初步选定聚氧化乙烯/十八烷基三甲基氯化铵的聚合物/表面活性剂复配体系作为研究对象，借助介观分子动力学模拟手段，计算了此体系的抗剪切能力及表面张力。发现此体系的抗剪切能力较聚合物、表面活性剂单一体系有明显提升，且体系的表面张力较纯表面活性剂溶液有所提高，初步证明此体系适用于消防减阻。同时从分子动力学角度深入分析了复配体系内聚合物、表面活性剂分子之间的作用机制，可为进一步寻找适用于消防减阻的聚合物/表面活性剂复配添加剂体系提供理论指导。

关键词: 消防减阻, 聚合物/表面活性剂复配体系, 介尺度, 分子模拟, 界面张力