Research On A Vibration Analysis Method For The Blade With Fluid-Structure Interaction

In the tubomachinery, fluid disturbance force acting on the blade is the key factor among many elements that causing blade vibration.In process of blade vibration, Campbell diagram is generally used to predict the resonance state of work status. But in the working range of aircraft engine, the several resonance points in Campbell diagram is not enough to judge the danger conditions and resonance phenomenon during the work of engine. Blade vibration still exists in the working area expect of resonance points. For this reason, the most effective method is to analyze the gas exiting force that results in the blade vibration. Vibration response of blade is directly solved and controlled in order to analyze the damage factor of blades.Air exists around the blade, and the speed and change of the displacement for the blades are determined by the air force distribution. However, the process of blade vibration will affect the distribution of air force surrounding the blades, which promotes the flow field structure deform. Therefore aerodynamic and structural factors must be combined to solve the details of the blade vibration.Based on the summary of the research methods of acroelastic, this paper would focus on gas exciting force prediction method which based on the multi-step method of fluid-structure interaction. The vibration of the plate blades was analyzed on the basis on multi-step coupling method with Workbench/CFX software. The work of the paper was mainly introduced as follows:1) This paper presented a prediction method for gas exciting force with fluid-structure interaction. It was a research that the models of rotor plate blade and surrounding fluid domain were created to simulate the situation of wake influence, which was carried out by Workbench and CFX software. The value of the aerodynamic forces on the surface could be got in the case of the final convergence by numerical simulation computation of fluid-structure interaction. The exciting force expression was established according to the relationship of the aerodynamic force values and the aerodynamic values.2) This paper analyzed the blade forced vibration response based on the final wake exciting force expression. The vibration characteristics of blade with fluid-structure interaction and without fluid-structure interaction were compared and analyzed.3) By changing the inlet angles in front of the stator plate blades, this paper analyzed the harmonic response of the blade with fluid-structure and finally got the discipline of harmonic response for the plate blade in different inlet angles.4) On the basis of above research, the influence of the dynamic stability for the rotor blade with fluid-structure interaction was analyzed at the different inlet angles about the stator blades.