延时膨胀泡沫的运动特性研究  

Movement characteristics of delayed expandable foam

作　　者：金良安[1] 王吉心[1] 迟卫[1] 曲翊[1] 

机构地区：[1]海军大连舰艇学院,大连116018

出　　处：《应用力学学报》2014年第3期435-439,494-495,共5页Chinese Journal of Applied Mechanics

摘　　要：针对舰船利用现有水幕系统施放泡沫幕难以同时满足施放距离远、滞空时间长的问题,深入研究了延时膨胀泡沫(DEF)的运动特性。将不同浓度的一水合柠檬酸(C6H8O7·H2O)和碳酸氢钠(NaHCO3)溶液在高压管路中以物质的量之比1:2充分混合,添加6%体积的水成膜泡沫液,制得DEF并由圆柱状喷口施放,测量其射程、体积的变化规律。结果表明:DEF运动的主要影响因素——曳力加速度af与其运动速度v的平方、瞬时发泡率δ的2/3次方成正比,而泡沫施放后δ是逐渐增加的,其施放初期的af远远小于普通泡沫,可大幅提高射程;在其降落阶段,δ的增加又有利于降低泡沫的降落速度,进而提高其滞空性能;当DEF最终发泡率A为4.0时,其平均射程可达普通空气泡沫的2.7倍,泡沫体积膨胀大约在2.5s内完成90%,对应af的体积因子δ2/3增大了2.4倍,滞空时间增大了1.55倍。研究结论可为泡沫型干扰幕技术的进一步丰富完善以及相应装备研制提供必要的理论和实验基础。Interfere foam curtain fired by countermeasure washdown system faces problems of contradictory indexes of firing range and existing time. This paper studies the movement characteristics of delayed expandable foam(DEF) which has been invented by us. DEF is made by mixing solution of citric acid monohydrate(C6H8O7·H2O) and sodium bicarbonate(NaHCO3) with different concentration in a high pressure duct. The molar ratio of the two solutes above is 1:2 and AFFF concentrate is added with the volume fraction of the mixture being 6%. The firing range and volume of DEF launched through a cylindric nozzle is measured. Results show that the drag force acceleration af of DEF increases in proportion to the square of velocity v and the 2/3 power ofinstantaneous expansion rate δ. Because of the continuous increase of δ, af of DEF is much less than that of common air foam consequentially, which can enhance the firing range distinctly; the increased δ is beneficial to raise the air resistance of falling foam drop, which can reduce the falling velocity hence increase the suspension time of DEF. Average range of DEF with final expansion rate A of 4.0 is 2.7 times more than common air foam. The expansion of the former reaches 90% in about 2.5s, the corresponding volume factor δ2/3 raises to 2.4 times, and the suspension time raises to 1.55 times. The research can offer theoretical and experimental basis for improving technique and equipment of interfere foam curtain.

关 键 词：泡沫 延时膨胀 运动 曳力 发泡率 

分 类 号：O351[理学—流体力学]