CAJ | 학술논문

为了进一步研究风力灭火机的灭火性能，并防止灭完火的区域死灰复燃，在风筒进口增加了超细干粉灭火剂进行喷射灭火。喷射式风力灭火机的性能主要体现在出口风速、射程和喷射的稳定性上，而后两者分别主要由灭火剂颗粒的喷出的速度和风筒内滞留灭火剂的量决定的。该文采用6MF-30型风力灭火机使用的风筒为原型验证仿真模型的可靠性，采用 CFD-DEM 耦合的方法对喷射式风力灭火机的工作过程进行仿真模拟。以风筒收缩角、灭火剂添加位置、风筒长度作为因素，按照二次正交旋转组合设计进行仿真试验，进行显著性检验和方差分析，建立了回归方程。结果表明：3个因素相对颗粒喷出速度和风筒内颗粒数都具有显著相关性，显著水平分别为P<0.0001和P<0.001，而这3个参考因素与出口风速无明显相关性；3个参考因素中风筒长度是对机械性能影响最大的因素。采用响应面法、加权法综合对最佳参数组寻优，发现喷射式风力灭火机收缩角取20°，灭火剂添加孔道距进风口140 mm，风筒长度700 mm时喷射式灭火机性能得以提高。采用该参数组的虚拟试验结果显示，颗粒喷出速度提高至41.24 m/s，同时风筒内颗粒数降低至209个。实体样机验证试验表明：采用该参数组设计的风筒可以有效提高喷射式风力灭火机的喷粉射程2.15 m，缩短灭火时间1.7 s且无复燃。该研究为风力灭火机风筒优化模拟提供了参考。
위료진일보연구풍력멸화궤적멸화성능，병방지멸완화적구역사회복연，재풍통진구증가료초세간분멸화제진행분사멸화。분사식풍력멸화궤적성능주요체현재출구풍속、사정화분사적은정성상，이후량자분별주요유멸화제과립적분출적속도화풍통내체류멸화제적량결정적。해문채용6MF-30형풍력멸화궤사용적풍통위원형험증방진모형적가고성，채용 CFD-DEM 우합적방법대분사식풍력멸화궤적공작과정진행방진모의。이풍통수축각、멸화제첨가위치、풍통장도작위인소，안조이차정교선전조합설계진행방진시험，진행현저성검험화방차분석，건립료회귀방정。결과표명：3개인소상대과립분출속도화풍통내과립수도구유현저상관성，현저수평분별위P<0.0001화P<0.001，이저3개삼고인소여출구풍속무명현상관성；3개삼고인소중풍통장도시대궤계성능영향최대적인소。채용향응면법、가권법종합대최가삼수조심우，발현분사식풍력멸화궤수축각취20°，멸화제첨가공도거진풍구140 mm，풍통장도700 mm시분사식멸화궤성능득이제고。채용해삼수조적허의시험결과현시，과립분출속도제고지41.24 m/s，동시풍통내과립수강저지209개。실체양궤험증시험표명：채용해삼수조설계적풍통가이유효제고분사식풍력멸화궤적분분사정2.15 m，축단멸화시간1.7 s차무복연。해연구위풍력멸화궤풍통우화모의제공료삼고。
The mechanic performance of ejecting pneumatic fire extinguisher is determined by the following parameters:air speed at funnel exit, outfire range and ejecting stability;and the second and third parameters depend on the fire extinguishing agent pellet’s velocity on funnel exit and the amount of fire extinguishing agent pellets detained in the funnel when extinguisher is working. In this research, the CFD-DEM coupling model was adopted to simulate the working process of ejecting pneumatic fire extinguisher, and the type of 6MF-30 pneumatic extinguisher was used to test the reliability of the coupling model. The funnel throat angle X1, the adding position of fire extinguishing agent X2, and the funnel length X3 were selected as the influencing factors, and total 23 experiments were conducted by the simulation model under the quadratic orthogonal rotation design. The virtual tunnel was designed according to the tunnel equipped to 6MF-30 pneumatic extinguisher. The virtual fire extinguishing agent pellets were found on the EDEM interface, coupled to the original CFD by Lagrangian model. The pretest results showed that this model had strong convergence which was proved by its stable airflow performance when running at the time of 0.2-0.25 s, and stable pellet number when running at 0.34 s. The air velocity at exit calculated by the CFD-DEM coupling model was similar to the theoretical value. It could be found that the number of aggregating virtual pellets detained in the region between the air tunnel and the fire extinguishing agent’s channel was consistent with the result of research by other scholars. The simulating experiment data were exported for analyzing. The average velocity in axial direction on each point at funnel exit was read by Fluent, and after subtracting the average value 197.550, the deviation data of the 23 experiments were got and selected as the outlet wind velocity (index Y1). The max virtual pellet velocities in axial direction monitored by EDEM within 0-0.4 s of all experiments were selected as the spouting velocity (index Y2). The vertical coordinates of every virtual pellet at 0.37, 0.38, 0.39, 0.4 s in all experiments were read by EDEM, and‘countif’ function was used to calculate the number of virtual pellet located in the tunnel (as assessment index Y3) when working. After the significant test and the variance analysis, the regression equation building was done by using SAS9.1. The result showed that the fire extinguishing agent pellet’s velocity on funnel exit and the amount of fire extinguishing agent pellets detained in the funnel were significantly correlated to the three factors (P<0.0001, P<0.001 respectively), but the air speed at funnel exit had no correlation with these factors. By using response surface method combined with weighting method, the optimal aggregative index could be obtained under the condition that the funnel throat angle was 20°, the adding position of fire extinguishing agent was 140 mm and the funnel length was 700 mm. Under this condition, the efficiency of ejecting pneumatic fire extinguisher was mostly improved. The virtual test designed by the optimized parameters showed that the fire extinguishing agent pellet’s velocity on funnel exit increased to 41.24 m/s, and the number of fire extinguishing agent pellets detained in the funnel decreased to 209. The verify test of the physical prototype indicated that the optimized parameters could improve the working effect of ejecting pneumatic fire extinguisher, which was manifested in extending the outfire range by 2.15 m, reducing the possibility of reburning and shortening the outfire time by 1.7 s.