基于冲蚀耦合的透平叶片自振频率修正模型

A Modified-Model for predicting vibration frequency of Turbine blade coupling particle erosion

基于叶片质量冲蚀率正比于颗粒累积质量这样的试验规律,本文提出了冲蚀环境下透平叶片弯曲自振频率计算的修正模型,将叶片冲蚀问题与叶片强度问题进行耦合。对某PFBC燃气轮机双级跨音速透平分别用5～50μm的石英砂和催化剂颗粒(颗粒相浓度分别为9 03×10-5%和4 19×10-5%)冲蚀数值模拟后,由该修正模型对透平叶片自振频率的变化进行了估算,结果表明,考虑了叶片冲蚀现象后,叶片自振频率随时间提高,提高幅度依叶片流道内颗粒浓度、颗粒材质的重度而异。这一模型为预报叶片安全状况提供了更有效的手段,有益于提高气固两相透平叶片安全监测的可靠程度。

The article puts forward a modifiedmodel for calculating vibration frequency of turbine blade based on the fact fhat erosion rate of blade is approximately liner to the accumulating mass of particles impacting the blade,thus coupling the influence of aerodynamicerosion problems in gassolid twophase turbine on the intensity problems of blade.After the numerical simulation of erosion in a twostage transonic turbine under 3D viscous turbulent flow field accounting for gassolid twoway coupling,the modified model is used to predict the frequency change of blade with time due to erosion(impinged by 5～50μm silica particles with concentration of 9.03×10-5% and catalyst particles with concentration of 9.03×10-5,respectively).The results exhibit that blade vibration frequency will increase with time and this tendency is highly dependent on the particle conentration and particle density.