基于曲面重构的飞机三维结冰数值模拟计算

在飞机结冰数值模拟中,采用多时间步长法可以准确模拟实际结冰情况。首先给出了三维结冰数值模拟方法,通过求解N-S方程计算空气流场、采用欧拉法计算水滴轨迹、求解质量和能量守恒方程计算结冰增长。对结冰后的结果数据进行重组,建立新的拓扑关系,采用非均匀双三次B样条曲面重构算法重构冰形曲面,得到几何模型,实现飞机三维结冰的多时间步长数值模拟。比较了单时间步长和多时间步长的计算结果;并与冰风洞试验数据及LEWICE预测数据进行对比,分析了不同时间步长对结冰外形的影响,得到了表面水收集系数随着时间的变化规律。结果表明,随着时间步长的不断缩小,水收集系数在机翼上表面不断增加,影响冰形的增长。时间步长越小,计算结果越接近试验数据,验证了曲面重构算法的正确性,说明多时间步长在结冰数值模拟方法中的优越性。

Numerical simulation of three-dimensional ice accretion based on surface reconstruction

In numerical simulation of ice accretion, the multi-time step method can accurately simulate the actual icing condition. First, the paper introduces numerical simulation method of three-dimensional ice accretion. The N-S equation is solved to calculate air flow field. Euler method is used to calculate water droplet trajectory. The mass and energy conservation equations are solved to calculate icing growth. Reorganizing icing date to establish a new topological relationship for surface reconstruction. The non-uniform bicubic B-spline surface reconstruction algorithm is used to reconstruct the ice shape surface. In this way, three-dimensional ice accretion is calculated with multi-time step numerical simulation method. Single time step and multiple time step are used to simulate ice accretion separately. The results are compared with the ice wind tunnel test data and LEWICE prediction data. Besides, the paper analyzes the influence of different time steps on the icing shape and obtains the law of surface water collection coefficient with various time. The results show that with the time step shrinking, the water collection coefficient increases on the upper wing surface which affect the growth of the ice shape. And the smaller the time step is, the closer the calculation result is to the experimental data. The results also verify the correctness of the surface reconstruction algorithm and the superiority of the multi-time step in the numerical simulation method of icing.