霜状冰结冰数值模拟研究

提出了一种三维霜冰结冰的数值模拟方法。基于欧拉-拉格朗日法计算空气-水滴两相流流场,获得了表面水滴撞击特性以及撞击量,求解质量守恒和能量守恒方程获得网格单元内的结冰量,三维霜冰的结冰计算程序采用用户自定义（UDF）编写,FLUENT提供的动网格功能实现了结冰后的网格重构。计算了4°攻角,液态水含量为1 g/m3,水滴直径20μm,结冰时间6 min,温度分别为-19.4°和-28.3°时NACA0012翼型的结冰,并与相关文献结果进行了对比,计算结果与文献实验结果吻合较好,验证了方法的合理性和可靠性。分析了不同的粒径、液态水含量、来流速度等对撞击特性以及结冰的影响,随着粒径、来流速度的增加,水滴收集系数、撞击区和结冰厚度增大,随着液态水含量的增加,水滴收集系数和撞击区是不变的,但是结冰厚度增加。

Numerical Simulation of 3D Rime Ice

A 3D rime icing numerical method was presented.The Eulerian-Lagranian model was employed to simulate the air-water two phase,and the distribution of impingement droplet was obtained.Mass and energy balance were established in a control volume,then ice accretion code was completed using UDF(User Defined Function),which was provided by FLUENT.Grid reconstruction after icing was accomplished by moving mesh,which was integrated in FLUENT.The method was validated by NACA0012 airfoil.Two examples were computed,the attack angles are 4°,LWCs are 1 g/m3,MVDs are 20μm,icing time is 6 minute,and the temperature are-19.4°and-28.3°respectively.The results were compared with literature,and they were agreed well.Then the influences of the MVD,LWC,and velocity to the collection coefficient and ice shape are computed and analysis.When the MVD or velocity is increased,the droplet collection coefficient,impinging area and ice thickness also increased,and when the LWC is increased,the droplet collection coefficient and impinging area do not change and the ice thickness is increased.