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采用改进的离散要素法(DEM)对严重事故中碎片床的形成过程进行二维数值模拟。针对传统的DEM模型中计算系数选取困难的问题,围绕时间步长对计算参数重新进行推导和组合,改进后的DEM能大大提高应用的效率。通过与一系列的实验在颗粒扩散角度、颗粒下落时间、形成碎片床的形状方面的系统对比,验证了模拟程序的有效性。
The modified discrete element method (DEM) was used to simulate the formation of debris bed in severe accidents. Aiming at the difficulty of selecting the calculation coefficients in the traditional DEM model, the calculation parameters are re-derived and combined around the time step. The improved DEM can greatly improve the application efficiency. The effectiveness of the simulation procedure is verified by a systematic comparison with the series of experiments in terms of particle diffusion angle, particle drop time, and the shape of the formed bed.