细水雾有效雾通量的称重法测量研究

Measurement of effective water mist flux by electronic balance

雾通量是影响细水雾灭火性能的关键参数之一,前人研究它对灭火性能影响时,通常分析的是细水雾的总通量.为了将与火焰或燃料发生相互作用的细水雾从总量中加以区分,定义这部分雾通量为有效雾通量.测量雾通量主要有两种方法,一种是量杯收集法,另一种是间接测量积分计算法.在量杯收集法的基本思路上,提出了有效雾通量的称重测量法.通过建立细水雾发生系统与电子天平实时称重系统,实验验证了称重法测量的可行性.结果表明:称重法可以实时、有效获得细水雾的有效雾通量;且不同高度平均雾通量随高度变化的规律与一定假设前提下的理论推导结果能够较好地吻合,由此得到了有效雾通量空间分布的近似计算方法.在计算获得了有效雾通量空间分布的基础上,如果通过实验得到有效雾通量与细水雾灭火性能的对应关系,就可以分析出不同雾场不同区域的灭火性能分布,有效减少灭火实验次数.

Water mist flux is one of the key factors in flame extinguishment, so total flux was usually discussed in former research works. In order to distinguish the portion of water mist that has a direct influence on the flame or fuel, effective flux was defined based on the current conception of water mist flux. Collecting tubes and the APV （adaptive phase/Doppler velocimeter） system are two ways currently employed to measure water mist flux. In order to measure the unstable water mist flux and improve the tube-collection method, a water mist generating system and an electronic balance were set up to validate the means of using electronic balance to measure the flux. It was proved that electronic balance can measure flux density effectively and in real-time. Meanwhile, fluxes of different heights have a good correspondence with the results of theoretic calculation. Ununiformity of the water mist field is the reason for the slight difference in results between the experiments and calculation. Some expressions were presented to calculate the dimensional distribution of effective flux density. A lot of fire suppressing experiments can be omitted using the calculation.