Crack Initiation And Propagation Mechanism Of Turbine Blade

With the continuous advancement of science and technology,turbocharging technology has been widely used.Turbochargers have become an important part of locomotive engines and are one of the important ways to improve engine efficiency and reduce emissions.In recent years,turbochargers have continued to develop in the direction of high speed,high power,and light weight,which has caused the working environment of turbine blades to become more and more severe.Frequent failures caused by excessive stress and cracks,resulting in significant losses,are urgently needed.The initiation and propagation mechanism of blade microcracks have been studied in depth.In this paper,ANSYS software is used to perform fluid-solid coupling analysis on turbine blades,and CFX is used to perform fluid calculations on turbine blades.The calculation results are imported into the steady-state thermal analysis and structural analysis modules,and the results of steady-state thermal analysis are also imported into the structural analysis module.Set the speed in the structural analysis module,calculate the coupling stress distribution of the blade,and make a simple analysis of the blade crack initiation mechanism according to the stress distribution,and determine the dangerous parts that are prone to cracks.Secondly,a semi-elliptical crack was inserted into the crack-prone part as the initial crack,and the stress intensity factor calculation was carried out for cracks of different sizes.A total of 10 sets of simulation analyses were carried out.The blade crack propagation mechanism was analyzed through the study of the stress intensity factor.Finally,the simulation analysis of the process of smooth crack propagation to instability under the action of fluid-solid coupling,calculated the change of the stress intensity factor value at different speeds,and analyzed the influence of each factor on the blade crack propagation through the study of the stress intensity factor.The simulation results show that the root of the blade on the outlet side is a dangerous location for micro-cracks,and the thermal load and centrifugal load have a greater impact on the coupling stress,which is the main factor for the initiation of the blade micro-cracks,and the centrifugal load is dominant in the crack propagation.And under high working conditions,when the crack length extends to 8mm,it faces the development of instability.