Numeric Analysis of Pneumatic Elasticity of Large Axial-flow Fan Blade

In the fluid-solid coupling of turbomachine, the elastor fluid-solid coupling is the most difficulty problem. In such kind of problem, it is needed to consider the elastic deformation of blade in the operating process, the influence of vibration on the flow field, and the reaction of oscillating flow field. The No.18 axial flow fan in Beijing subway is taken as an example, in the coupling state with the consideration of the interaction between blade deformation and flow field, the calculation method of gas-solid coupling of fan blade is discussed. REPEATABILITY software is adopted to carry out flow field calculation and ANSYS software for structure calculation, MFX-ANSYS/CFS is taken as data coupling platform, and weak coupling zoning method is applied for numerical simulation analysis of the pneumatic elasticity of fan blade. And it is compared to the situation that is without elastic deformation considered. It is found that the maximum stress with pneumatic elasticity considered is almost two times of the maximum stress without pneumatic elasticity considered, and the corresponding safety coefficients are in great difference. Without the pneumatic elasticity considered, it is easy to overestimate the safety of blade structure. Through analysis of the influence of elastic deformation on the safety of blade structure, the necessity and importance of analyzing the pneumatic elasticity of blade is indicated.