Analysis Of Dynamic Characteristics Of Turbofan Engine With Intermediate Support

With the rapid development of civil aviation,the double-rotor turbofan engine with intermediate support has been widely used.The intermediate support strengthens the coupling of the high and low-pressure rotors and makes the vibration characteristics of the rotor system more complex.Therefore,it is of great significance to study the dynamic characteristics of the rotor system.Any study of high depth and complexity needs to be supported by basic research.There are mainly two basic studies on rotor dynamics.The first is the calculation of the critical speed,which is designed to make the rotor system work speed far away from the critical speed;The second is the calculation of the unbalance response,mainly to analyze the rotor system components for the unbalance excitation amplitude.In this paper,the rotor system of a doublerotor turbofan engine with intermediate support is reasonably modeled.At the same time,three models of single-low pressure rotor,single-high pressure rotor and double-rotor are obtained.Firstly,the influence of the coupling action of the intermediate support on the dynamic characteristics of the low-pressure rotor is explored,and the influence of the coupling action of the intermediate support on the critical speed of the low-pressure rotor is studied through the comparative analysis of the critical speed.Then,the unbalance response calculation was compared and analyzed,and the unbalance acted on different positions were compared and studied,and then the influence of coupling action of the intermediate support on the amplitude of different positions of the low-pressure rotor was analyzed.The results show that the coupling action of the intermediate support makes the working speed of the low-pressure rotor far away from the critical speed,which is of safety significance.And the amplitude of the response of the components of the low-pressure rotor to the unbalanced excitation is reduced.Finally,the influence of the coupling action of the intermediate support on the dynamic characteristics of the high-pressure rotor is explored.And the influence of the coupling action of the intermediate support on the critical speed of the high-pressure rotor is studied through the comparative analysis of the critical speed.Then,the unbalance response calculation was compared and analyzed,and the unbalance acted on different positions were compared and studied,and then the influence of coupling action of the intermediate support on the amplitude of different positions of the high-pressure rotor was analyzed.The results show that the coupling action of the intermediate support makes the working speed of the high-pressure rotor close to the critical speed,which has a potential safety hazard.The maximum amplitude of the response of the components of the high-pressure rotor to the unbalanced excitation is reduced,but the amplitude response times increase.In this paper,the finite element method is used to explore the influence of the coupling action of the intermediate support on the dynamic characteristics of the high pressure and lowpressure rotors from the basic research,which lays a foundation for the further dynamic research and has a certain reference significance in engineering practice.