农业工程学报Issue(8)：104-111,8.DOI:10.3969/j.issn.1002-6819.2015.08.016
基于CFD-DEM耦合法的灭火机风筒优化与试验
Simulation optimization and test of fire extinguisher funnel based on CFD-DEM coupling method
摘要
Abstract
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.关键词
灭火机/计算机仿真/优化/CFD-DEM耦合/风筒Key words
fire extinguishers/computer simulation/optimization/CFD-DEM coupling/funnel分类
农业科技引用本文复制引用
蒋梅胜,李恒,李林书,彭凯,王顺喜..基于CFD-DEM耦合法的灭火机风筒优化与试验[J].农业工程学报,2015,(8):104-111,8.基金项目
国家公益性行业（农业）科研专项 （）
