中文摘要：

建立了粒子在重力、流体阻力和随机力作用下的烟幕扩散模型，测试了某种纳米碳纤维材料在烟幕箱里的扩散，利用线性回归分析估计了测试光路上的质量浓度，计算了烟幕的沉降速率。分别用本文建立的模型和随机游走模型模拟了该材料在烟幕箱里的扩散过程，模拟计算得到的质量浓度和沉降速率表明，本文建立的模型所模拟的结果更接近于实际测量结果。

英文摘要：

In this paper, the smoke screen dispersion model is formulated in a Lagrangian way. The formulation is based on the assumption that tracer particles are affected by gravity, resistance and random force. The dispersion experiment of a kind of carbon nano-fibers material is simulated by the model established in the paper and the random walk model. The concentrations are estimated based on linear regression analysis and computation of the sedimentation velocity of smoke screen. The simulation results are compared with the test results, which show the model established in the paper is more accurate than the random walk model.