Blade Erosion Research In Full Three Dimensional Viscous Flow Field

Turbomachine is an energy conversion machinery which is treated as one of the most important contemporary energy equipment. It is widely used in energy, metallurgy, petroleum, chemical industry and other fields, playing a decisive role in each pillar industry of national economy. The improvement of turbomachinery technology has a great influence on the constructionof national economy and defense construction, being the key to realize the sustainable development of core technology. Therefore, it is of great strategic significance to actively carry out the study on the mechanical properties of turbomachine.As a kind of turbomachine, flu gas turbine has a complex working medium. The medium contains flu gas that mixed with water vapor, nitrogen, carbon dioxide and other components, and a lot of tiny catalyst or ash particles that can not be completely filtered. Then these solid particles will creat blade erosion caused by repeat impact collision during the operation. The sustained particle erosion will not only increase the damage of blade surface, change the blade shape, deteriorate the blade aerodynamic performance, but also change the turbine blade vibration characteristics, shorten the service life of blade, even endanger the safety of the unit when reached certain extent. As a result, the erosion is one of the significant influences to the turbine operation efficiency and safety. In order to effectively reduce and overcome the phenomena, particle erosion mechanism is required to study. It is of very practical significance to improving the economic benefits and increasing safety and reliability of the unit operation that carrying out numerical simulation of particle erosion distribution rule, erosion control research and blade life prediction in full three dimensional viscous flow field.CFD technology is used in this paper to research particle erosion characteristics in the flue gas turbine with the help of commercial software Phoenics. Euler-Lagrange method is adopted to simulate 3-D viscous turbulent flow field of a one-stage gas turbine. Gas-solid two-way coupling is realized to analyze the trajectories and slip of particles, with diameter 5~50μm, calculate the mass erosion rate based on the impact velocity and attack angles, then put forward the variation with time of turbine blades natural frequencies correlation model based on the rate, predicting the blade life. Simulation the influences of surface elastic properties on distribution of blade erosion, then explore erosion control and law, put forword a kind of new ideas about blade erosion control based on coefficient of elastic restitution.For a more intuitive understanding of the erosion tolerance of material, hot wind tunnel erosion experiment is also done in this paper. Comparison experiments are conducted between the substrate of X20Cr13 and the specimen with steel-bead injection under the condition of 200℃ and 300℃. Then put forward the material optimization scheme and explore the steel-bead effect on the erosion tolerance, providing a reference for blade surface strengthening technology.