圆弧面动态空气喷涂数值模拟

采用欧拉—欧拉法，建立由两相流喷雾流场模型和碰撞黏附模型构成的喷涂成膜模型.将圆弧面外、内壁喷涂和平面喷涂的控制域划分为运动区域和静止区域，并分别生成计算网格，采用弹性光顺模型结合局部重构模型实现运动区域中网格的动态变化.基于有限体积法，采用二阶迎风格式对模型进行离散，采用PC-SIMPLE算法求解离散后的模型，得到圆弧面轴向喷涂和平面喷涂的喷雾流场和涂层厚度分布.喷雾流场仿真结果表明：在扇面控制孔气流的冲击下，喷雾流场在Y方向被压扁，在X方向扩张；由于喷枪的移动，喷雾流场向喷枪移动的后方略微倾斜.涂层厚度分布结果表明：圆弧面内壁喷涂的最大涂层厚度小于平面喷涂，外壁喷涂的最大平面喷涂涂层厚度大于平面喷涂；圆弧面内壁喷涂的涂膜宽度大于平面喷涂，外壁喷涂的涂膜宽度大于平面喷涂.数值模拟得到的喷涂涂膜厚度分布与实验结果吻合，证明所建立的喷涂成膜模型和动网格模型可以用于平面和圆弧面喷涂成膜模拟.
Abstract: A paint deposition model was established comprising a two-phase spray flow field model and an impinging and sticking model based on the Euler-Euler approach. The control domain for spray painting of the outer and inner arc surfaces and a plane surface were divided into moving region and stationary region, where the calculation meshes were generated, respectively. The spring smoothing model coupled with the region remeshing model was adopted to achieve the dynamic change of the meshes in the moving regions. Based on the finite volume method, the model was discretized by the second order upwind scheme and the discretized equations were solved by the PC-SIMPLE algorithm. The results of the spray field simulation show that the spray flow field is flattened in Y direction and spreads along the X direction by the impact of the air stream provided by the fan holes, and the spray field slightly tilts back away from the spray gun due to the motion of the spray gun. The results of the paint thickness distribution show that the maximum value of the film thickness distribution on the outer arc surface is smaller than that on the flat plane, while that on the inner arc surface is bigger than that on the flat plane; the film width on the inner arc surface is larger than that on the flat plane, while that on the outer arc surface is smaller than that on the flat plane. The simulated results are in good agreement with the experiments, which verifies the feasibility of the proposed models for the numerical simulation of dynamic spray painting.