煤块冲击破碎粒度分形特征

Fractal character of impact crushing granularity of coal lumps

煤块冲击破碎后粒度分布具有分形特征,据分形理论建立煤块冲击破碎粒度分形模型,对不同矿区煤块进行冲击破碎试验。在不同试验条件下对破碎煤块筛下质量累积概率进行函数拟合,结果表明:分形模型能很好地描述煤块冲击破碎后的粒度分布特征,粒度分形维数能评价煤块冲击破碎效果。采用Matlab软件建立粒度分形维数与试验参数间二次方模型,该模型预测结果与试验结果平均误差为2.51%,可满足预测误差要求,为控制煤块冲击破碎后产品粒度分布提供理论依据。

The impact-crushing granularity distribution of coal lumps possesses a fractal character. A fractal model for impact crushing granularity of coal lumps was proposed based on fraetal theory. The impact crushing tests of coal lumps in different mines were conducted. The under-sieve mass cumulation probabilities of crushed coal lumps under different tests conditions were fitted with curves. The fitted curves showed that the fractal model is suitable for the granularity distribution of crushed coal lumps, and the granularity fractal dimension is a important parameter for the evaluation of impact crushing effect for coal lumps. A quadratic model between granularity fractal dimension and test parameters was established with Matlab software. The average error between the predicted results with the model and test ones was 2.51 percent and meet the requirement of the prediction error. The study results provided a theoretical foundation for controlling granularity distribution of crushed coal lumps.