为提高回转窑内煤粉燃烧效率，实现回转窑的节能运行，建立了回转窑内煤粉燃烧数学模型。通过控制单一变量和设计多指标正交试验工况，研究了空气过剩系数、煤粉粒径、旋流角度、内外风量比4个因素对回转窑内煤粉燃烧的影响，得到了最优操作参数组合。结果表明，随着空气过剩系数和煤粉粒径增大，火焰长度增大、火焰直径减小，火焰变得细长。随着旋流角度增大，火焰形状变短变粗。随着内外风量比增大，火焰长度先增大后减少、火焰直径先减少后增大。四个因素按影响程度从高到低排序依次为煤粉粒径、内外风量比、空气过剩系数、旋流角度。回转窑内煤粉燃烧的最优操作参数组合为空气过剩系数1.1、煤粉粒径40 μm、旋流角度25°、内外风量比0.9。相较原始工况，优化工况的火焰长度和火焰直径分别增大了8.9%和13.9%。

Rotary kiln is a high-energy consumption equipment widely used in metallurgy, chemical industry, environmental protection and other fields. As the main energy source of the thermal process of the rotary kiln, the efficiency of fuel combustion is directly related to the energy-saving operation of the rotary kiln. In order to improve the pulverized coal combustion efficiency in the rotary kiln, the pulverized coal combustion process in the rotary kiln was numerically simulated by ANSYS Fluent 19.0 software. By controlling a single variable and designing a multi index orthogonal test condition, the influence and significance of air excess coefficient, pulverized coal particle size, swirl angle, ratio between internal and external air volume on the pulverized coal combustion in the rotary kiln were analyzed. The influence rules of each factor on pulverized coal combustion and optimal working condition were obtained. The results showed that the increase of air excess coefficient and pulverized coal particle size increased the flame length, reduced the flame diameter and make the flame slender. The increase of swirl angle shortened and thickened the flame shape. With the increase of the ratio of internal and external air volume, the flame length first increased and then decreased, and the flame diameter first decreased and then increased. The four factors ranking in a decreasing order of in?uence were the pulverized coal particle size, ratio between internal and external air volume, air excess coefficient, and swirl angle. The optimal operating parameter combination of pulverized coal combustion in rotary kiln were air excess coefficient of 1.1, pulverized coal particle size of 40 μm, swirl angle of 25°, ratio of internal and external air volume of 0.9. Compared with the original working condition, the flame length and flame diameter of the optimized working condition increased respectively by 8.9% and 13.9%.