电热除冰的热力耦合特性及其对冰层的影响研究

Study on coupled thermo-mechanical characteristic and its effects during the process of electrothermal deicing

采用计算和实验相结合的方法,初步研究了电热除冰过程中的热力耦合特性及其对冰层的影响。在电加热条件下,耦合外部气动力载荷的作用,采用有限元方法计算了不同热流密度下表面冰层和蒙皮间界面法向和切向应力的分布,比较了加热/不加热条件下界面法向和切向应力分布的差别,研究了冰层最大主应力随热流密度的变化规律。研究发现,电加热条件下,在表面冰层融化前,热力耦合特性将造成冰层内部应力的显著增加,从而造成冰层局部区域的破裂,加速冰层的破坏。同时,设计的原理性实验结果验证了热力耦合特性对冰层的破坏影响。研究结果对于电热除冰理论和除冰技术的发展有现实意义。

With computational and experimental method combined,the coupled thermo-mechanical characteristic in the ice is studied during the process of electrothermal deicing.The characteristics of interface normal and shear stress distributions between ice and airfoil are studied under different heat fluxes coupled with aerodynamic loading conditions by finite element method in this paper.The differences of normal and shear stress distributions between heated and unheated conditions are analyzed.The effects of heat flux on maximum principal stress are investigated.The study shows that coupled thermo-mechanical characteristic leads to remarkable increasing of stress in the ice under the condition of electrothermal deicing.Consequently,it results in crack in the ice and speeds up ice shedding before ice layer at surface begins to melt.The conclusion is validated by test for principle.The study will provide the technical support for the development of new deicing technique.