Research On Vibration And Multi-Field Coupling Mechanics Characteristic Of Bladed Disk System In Aero-Engine

The aero-engine as the heart of the aircraft,withstand the load of high temperature, high pressure,high-speed.For a long time,the major bottleneck restricting the development of high-performance engines is always operational reliability and structural integrity.One of the key problems is the vibration and intensity of bladed disk system in high-speed rotation.Bladed disk system is the combined structure constituted by blades and disks of the turbine or the aero-engine compressor connected by tenon and mortise.Bladed disk system is an important part of the aero-engine, one of the critical rotating parts of the engine,its design quality is directly related to the pros and cons of the engine performance and safety in using.In practice,the examples are not uncommon that engine failure due to the destruction of the blades.Therefore,designing on the engine blades,the strength design problem of the blades must be paid enough attention.With the increase of aero-engine’s thrust-weight ratio and the stress level enhancement of the disks,the disk slot is one of the weakest parts in the disks.And cracks are the multiple failures.Low-cycle fatigue failures occurred mostly in the serious stress concentration position at the disk mortise.After the shards of the broken disks penetrate the engine casing,they may cut fuel line and the operating system,also penetrate the fuel tank, posing a serious threat to the safety of the aircrafts.Furthermore,Extensive studies show that the engine major accidents related to the high-cycle fatigue of the blade vibration.lt is an important reason for producing high-cycle fatigue on the blades that the bladed disk system coupled vibration.Therefore,it is crucial role to enhance structural integrity and operational reliability of the aero-engine that the vibration and multi-field coupling mechanics characteristic research of bladed disk system in aero-engines.This paper takes the engine single-stage bladed disk system in the compressor as a research subject.firstly,it studys the vibration characteristics of the tuned and mistuned bladed disk system, and the dynamic response characteristics of the tuned and mistuned bladed disk system contacting with the bladed disk tenon under the static blade tailed flow excitation, propose prestressed fixed interface and free interface substructure mode synthesis super-element method.once again,the paper analyzes the dynamic response characteristics of the tuned and mistuned bladed disk system with the blade root friction damper under the static blade tailed flow excitation.use the lumped parameter model for the blade disk sector in three freedom degrees based on microslip friction theory.once more, it study to optimize the blade arrangement order of mistuned bladed disk system by the lumped parameter model for the blade disk sector in two freedom degrees based on the improved genetic algorithm and the ant colony algorithm,the system vibration reduction is the optimization objective.finally,use the finite volume method for the aerodynamic and heat transmission analysis of blade channels and the finite element method for the structure analysis of bladed disk system,it is based on Kriging model to transfer the load data information of coupling interfaces and the assumption elastomer to update the flow field grid of blade channels.It realizes the thermal-flow-structure multi-field coupling mechanics characteristic analysis of the bladed disk system based on the alternative iteration indirect coupling. Specifically,complete the work of this article is as follows:(1) When we use the prestressed substructure mode synthesis method,the prestressed whole structure analysis before substructure analysis.Due to the large computational complexity,it proposes prestressed fixed interface and free interface substructure mode synthesis super-element method.Take Matlab GUI as the platform combining Matlab and Ansys,so the vibration and dynamic characteristics analysis software for the bladed disk system is developed.as a platform of it,analyze vibration characteristics of the tuned and mistuned bladed disk system,and the dynamic response of the tuned and mistuned bladed disk system contacting with the bladed disk tenon under the static blade tailed flow excitation in the front stage.Compare and analyze the bladed disk contact form effect on the vibration and dynamic characteristics of bladed disk system.(2) To the current situation at present,most of research use the macro-slip model analysis of forced response of mistuned bladed disks with dry friction damping.a few of research use micro-slip model for the blade roots with non-linear dry friction effect on one and several blades,and small number of studies on the mistuned bladed disk system.It studys dynamic response characteristics of tuned and mistuned bladed disk system with the blade root friction damper under the static blade tailed flow excitation by the iterative solution of the harmonic balance method,and use the lumped parameter model for the single blade disk sector in three freedom degrees based on microslip friction theory.Compare and analyze to have blade-root frictional dampers or not effect on the vibration localization degree and dynamic characteristics of bladed disk system.(3)Introduce intelligent optimization algorithms to optimization vibration reduction arrangement of mistuned bladed disk system. It proposes two kinds of the goal functions for the system vibration reduction to optimize the blade arrangement order of mistuned bladed disk system by lumped parameter model for the blade disk sector in two freedom degrees based on the ant colony algorithm and the improved genetic algorithm.Then compare with the results of sequence and random arrangements,and verify the validity of method in this paper.(4) Use the finite volume method for the aerodynamic and heat transmission analysis of blade channels and the finite element method for the structure analysis of bladed disk system. To the shortcomings of current transmission method for the load data information of coupling interfaces.The transmission method for the load data information of coupling interfaces based on kriging model is proposed,and it realizes to transfer accurately from the aerodynamic and heat load of blade channels to the structure field of the bladed disk system and from the structural deformation of blades to the flow field of blade channels.Due to the aeroengine blade deformation under load,it introduces the finite element method to the flow field grid updating of blade channels.The flow field grid updating strategy of blade channels based on the assumption elastomer theory is proposed,and it realizes high quality updating on the the flow field grid of blade channels. As a platform of Matlab GUI,call Fluent and Ansys by matlab,it realizes to integrate the software of the thermal-flow-structure multi-field coupling mechanics characteristic of the bladed disk system.As an computing example of the compressor bladed disk system,compare and analyze the mechanics characteristics and the aerodynamic characteristics of the bladed disk system under multiple loads and multi-field coupling function, verify the reliability and accuracy of the software.