飞机三维结冰模型及其数值求解方法

 对飞机结冰外形进行纯三维数值模拟,是目前飞机结冰预测中的一大难点。为了建立三维结冰数值模拟方法,基于Messinger的二维结冰模型,提出了一种考虑液态水溢流效应的三维结冰计算模型,并针对该模型建立了表面单元内溢流水流动的分配方案、发展了相应的迭代求解方法。采用本文方法对MS-317后掠翼结冰进行了计算,并与实验和Lewice3D的计算结果进行了对比。研究结果显示：本文方法具有较好的收敛性,计算的霜冰和明冰外形均与Lewice3D计算的冰形一致;对于霜冰和结冰时间较短的明冰,本文计算的冰形与实验吻合较好;对于结冰时间较长的明冰,本文计算的冰形与实验对比还有一定差异,但冰生长的总体趋势和大致体积与实验一致。同时,对比了MS-317无后掠翼与有后掠翼结明冰的外形,发现机翼后掠导致的三维溢流效应对结冰外形有明显影响,因此,对于三维结冰分析,如果用二维截面的结果来代替三维结果,其合理性还需验证。

Numerical Method of a Three-dimensional Ice Accretion Model of Aircraft

A major difficulty in the prediction of aircraft icing is to calculate the three-dimensional ice shape on the surface of an aircraft. The main purpose of this article is to establish a numerical method for calculating the three-dimensional ice accretion. Based on the classic icing model proposed by Messinger, a three-dimensional model is presented in the article which takes into consideration the effect of runback water. Then the method of deciding the flowing direction and flux of the runback water on the surface cell is given, and an iterative algorithm for solving the model is developed. Ice accretion on an MS-317 swept wing is calculated, and the consequent ice shape is compared with that of an experiment and Lewice3D. The results show that the convergence of this method and arithmetic is good, and both rime and glaze ice shape agree well with the results of Lewice3D. For rime ice and short time glaze ice, the computational results are in good agreement with experimental data; for long time glaze ice, there are some discrepencies between the computational and experimental shape. However, the overall growth patterns and size of ice is reproduced well. The glaze ice shape of a non-swept wing is also compared with that of a swept wing, which shows that the three-dimensional effect of runback water caused by the swept wing affects icing significantly. Therefore, further verification is necessary in trying to represent the ice on a three-dimensional body by the ice on two-dimensional cross-sections of the body.