Similarity experiment on multi-source dust diffusion law in fully mechanized caving face

In order to understand the regularities of multi-source dust diffusion and distribution in a fully mechanized caving face, similar numbers were derived on the basis of similarity rule and kinematic equation of gas-solid two-phase flow. In addition, a scaled test model was constructed to simulate dust diffusion during coal cutting, support advancing, coal caving, transshipping and other multi-operations under the conditions of 1.0, 1.5, 2.0, 2.5 m/s wind velocity and 1.69%, 2.63%, 3.83%, 4.87% moisture content. Results indicate that the wind velocity has a great impact on each dust source while the outcome of the impact varies according to different situations. The optimal wind velocity is 1.5 m/s. Moreover the moisture content of coal dust significantly affects dust diffusion, and the optimal moisture content should not be less than 3.8%. From these results, it is concluded that the superimposed effect of the multi-source dust concentration distribution is obvious, therefore the comprehensive measures of dust prevention and reduction should be taken in practice. ©, 2015, China Coal Society. All right reserved.