摘要
为研究无氟泡沫灭火剂入射角度对其油面铺展效果的影响,试验测试和数值模拟了不同工况下无氟泡沫灭火剂在油面上的铺展过程.结果表明:无氟泡沫灭火剂铺展过程中后期以表面张力为驱动力的铺展速度较小;无氟泡沫灭火剂覆盖油面所需的铺展时间与其入射角之间符合指数下降函数,其中77°时泡沫灭火剂铺展最高效;不同方向上泡沫流体的速度差值随其入射角度和湍流脉动长度增加而变小.无氟泡沫灭火剂铺展的最高效入射角度研究方法和结果为消防泡沫喷射角度的选择提供参考.
Abstract
To investigate the impact of incident angles on the spreading behavior of fluorine-free foam extinguishing agents,experimental tests were conducted on a typical angle.Subsequently,numerical simulations were carried out to validate the computational model,which was then utilized to simulate the spreading process at various incident angles.The findings indicate that the spreading dynamics of fluorine-free foam extinguishing agents on the oil surface are primarily governed by gravity initially and later by surface tension.Moreover,the spreading velocity controlled by surface tension is observed to be slower compared to that governed by gravity.Upon complete coverage of the oil surface by the fluorine-free foam extinguishing agent,piecewise fitting results were obtained for the spreading time and incident angle.Specifically,an exponential decline function with R2 of 0.99 was identified within the incident angle of 60° to 75° and a linear decline function with R2 of 1 was identified within the incident angle of 80° to 90°.Furthermore,the overall fitting function for all spreading times and respective incident angles exhibited an exponential decline trend with R2 of 0.99.Notably,the optimal incident angle for the fluorine-free foam extinguishing agent was determined to be at 77° based on efficiency considerations.Moreover,as the incident angle surpasses 75°,the turbulent region expands,extending beyond the oil surface area.Interestingly,for a constant incident angle,the maximum turbulent kinetic energy exhibited by the fluorine-free foam extinguishing agent on the oil surface diminishes over time.The fitting outcome correlating the maximum turbulent kinetic energy with time corresponds to a linear regression decline function with R2 of 0.99.Furthermore,as the incident angle of the foam extinguishing agent escalates,the velocity differentials across various directions diminish,and there is a fluctuation in the maximum spreading velocity—initially decreasing and subsequently increasing.The exploration into the incident angles of fluorine-free foam extinguishing agents not only presents valuable research insights but also offers a practical approach for selecting optimal angles pertaining to foam extinguishing agent applications.
基金项目
江苏省科技副总项目(FZ20211438)
江苏省产学研合作项目(BY20221168)
泰州市科技支撑计划(社会发展)项目(TS202209)
江苏省研究生科研与实践创新计划项目(KYCX22-3117)
维普
万方数据