基于叠加效应的拉瓦尔喷管结构参数优化设计分析

Optimal Design of the Structure Parameters in Laval Nozzle Based on Stack Effect

采用基于CFD-DEM耦合的数值模拟方法对拉瓦尔喷管进行结构优化分析,并利用基于四因素、三水平的正交试验法探讨了结构参数对拉瓦尔喷射器出口气压的影响。结果表明:基于叠加效应的喷射器有利于粉体被吸入喷射器;拉瓦尔喷管喉管越长、管径越窄,收缩管的锥角越小,扩张管的锥角越小,都将造成喷射器出口压力增大;拉瓦尔管的出口压力受喉管长度影响最大,其次是喉管管径,再次是收缩管的锥角,最后是扩张管的锥角;通过增加一级拉瓦尔喷管以及增加喉管长度,可以提高进料的流畅性,同时有助于粉料更远距离的输送。

The structural optimization in Laval nozzle is analyzed by the numerical simulation based on CFD-DEM coupling method,and the effect of structure parameters of Laval nozzle on the outlet pressure of the nozzle is discussed through the orthogonal test with 4 factors 3 levels.The results show that the injector based on the stack effect is conducive to draw the powder into the injector;when the throat length becomes longer,the diameter of the throat becomes narrower,the cone angle of the contraction tube or the diffusion tube becomes smaller,the outlet pressure of Laval nozzle will increase.The outlet pressure of the Laval nozzle is most affected by its throat length,followed by the tube diameter,again the cone angle of the contraction tube,and finally the cone angle of the diffusion tube.By adding the primary Laval nozzle and increasing the length of the throat,the smoothness of the feeding can be improved,and the powder can be transported over longer distances.