基于分形统计强度理论的煤颗粒冲击破碎概率研究

基于分形统计强度理论对煤颗粒的冲击破碎概率进行研究.以Hertz接触假设为基础,得到煤颗粒冲击破碎概率与最大接触压应力之间的函数关系,并结合碰撞动力学理论,建立了冲击破碎概率的分形模型.对不同矿区工作面的煤颗粒进行冲击破碎试验,统计分析表明:分形模型可以对煤颗粒的冲击破碎概率进行很好的描述,冲击破碎概率与冲击速度在对数坐标中为线性关系.通过试验确定分形模型的分形维数和破碎常数,可以得到不同冲击速度下煤颗粒的冲击破碎概率以及煤颗粒全部破碎需要的冲击速度,为冲击破碎效果评价以及冲击速度的确定提供了理论指导.

IMPACT CRUSHING PROBABILITY OF COAL PARTICLES BASED ON FRACTAL STATISTICAL STRENGTH THEORY

The impact crushing probability of coal particles was investigated based on fractal statistical strength theory. The function relations between impact crushing probability of coal particles and maximum contact pressure stress were obtained by the hypothesis of the Hertz contact. Combined with the impact dynamics theory, the fractal model of impact crushing probability was established. The impact crushing experiments of coal particles in different mines were taken. The statistical analysis shows that the impact crushing probability and impact velocity are linear relation on the logarithmic coordinate, which indicates that the impact crushing probability of coal particles is well described by the fractal model. The impact crushing probability of coal particles under different impact velocity and the needed impact velocity crushing all coal particles, which provide the theoretical direction for the evaluation of impact crushing effect and the determination of the impact velocity, can be both obtained after the fractal dimension and the crushing constant of the fractal model are determined by experiments.