大型轴流风机叶片的气动弹性数值分析研究

在叶轮机械的流固耦合中以弹性体流固耦合问题最具难度。在这类问题中，需要考虑叶片在运转过程中的弹性变形与振动对流场的影响以及振荡流场的反作用。以北京地铁18号专用轴流风机为例，在考虑叶片变形和流场之间相互影响的耦合状态下，探讨机叶片气固耦合问题的计算方法。采用CFX软件进行流场计算、ANSYS软件进行结构计算，以MFX- ANSYS/CFX为数据耦合平台，应用弱耦合分区法对风机叶片的气动弹性进行数值模拟分析。并与不考虑叶片弹性变形的情况进行对比，发现考虑气动弹性的最大应力几乎是不考虑气动弹性的最大应力的两倍，相应的安全系数相差较大，不考虑叶片的气动弹性容易高估叶片结构的安全性。分析考虑弹性变形对叶片结构安全性的影响，说明叶片的气动弹性分析的必要性和重要性。

Numeric Analysis of on the 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.