The Remanufacturability Evaluation Study Of Centrifugal Compressor Impeller Based On The Very High Cycle Fatigue

With the rapid development of economy, the shortage of resource is increasingly serious in recent years, while the remanufacturing is one of the optimal ways to solve this difficulty. Remanufacturing can save money, energy, material and protect environment. The compressor impeller is widely used in industry, and it becomes a good remanufacturing object with high additional value and manufacturing cost. However, the remanufacturing of compressor impeller is difficult due to the complex working condition and extra-long working time. The research of very high cycle fatigue property of FV520B-I provides guidance for fatigue life design and fatigue failure prevention of centrifugal compressor impeller. And it lays the foundation for remanufacturability evaluation of impeller.In this paper, the load and stress distribution of centrifugal compressor impeller in the working condition of normal, stall and surge is analyzed using Fluent. It is found that the larger stress concentration exists at the contact position between the front end of blade and cover disk as well as leaf disk, where fatigue damage is apt to occur. The field distribution of the edge and internal crack tip are obtained by fracture and damage mechanics. It is clear that the field distribution of internal crack tip is similar to the edge crack, while the value is small.The very high cycle fatigue property of FV520B-Ⅰ, compared with the experimental result of conventional frequency, is studied with ultrasonic fatigue testing. The ultrasonic fatigue testing data is modified with the Basquin formula, and the modified fatigue strength σα=410MPa, which accords with the actual situation. Due to the difficulty of fatigue strength testing of compressor impeller, the translation model of impeller fatigue strength data based on modified gray relational grade, combining with the influence of various factors, is established to predict the fatigue strength of unknown inpeller using existing data.In this paper, a life model of very high cycle fatigue of FV520B-Ⅰ, combining with the crack initiation life and propagation life, is established based on microcosmic dislocation theory, energy theory and Paris formula. The residual life of inpeller, crack propagation and the size and distribution of initial crack are analyzed with the deterministic and probabilistic fracture mechanics comprehensively, which evaluates the remanufacturability of inpeller. The conprehensive evaluation method and model ofremanufacturability of inpeller are established by the evaluation models of technical, economic, environmental and timeliness.This study not only obtains the very high cycle fatigue property of material, but also has certain reference value to evaluate the remanufacturability of centrifugal compressor impeller.