Parameters Identification Of Inter-Blade-Coupling Vibration Based On Blade Tip Timing

In order to grasp the blade vibration information in real time to prevent blade failure, the widely used non-contact vibration measurement technology is blade tip timing method. Blade Tip-Timing signal is under-sampling, in order to know the information of blade vibration, the key technology is the establishment of vibration parameters identification algorithm. At present the widely used Blade Tip-Timing algorithm is based on single degree of freedom(single-dof) model, two or more vibration peaks occur and two peaks are very close to apart when there is inter-blade-coupling vibration, this method is unable to identify the vibration parameters of two peaks at the same time. We can use curve fitting method based on two degrees of freedom model(2-dof) to fit out inter-blade-coupling vibration parameters of the two peaks at the same time, and the blade Tip-Timing algorithm based on single degree of freedom model was improved to make it applicable to inter-blade-coupling vibration parameters identification based on 2-dof. This method can not only improve the accuracy of the inter-blade-coupling vibration parameters identification, but also identify vibration parameters of the two peaks at the same time.The main work is as follows:1. The inter-blade-coupling vibration theory based 2-dof are deduced, studied the impact of inter-blade-coupling on the blade vibration parameters identification. Develop a set of 4 blades simulation software, it can simulate synchronous vibration、 asynchronous vibration 、the whole blade-disk vibration and other different types of blade vibration signal, and the simple analysis has carried on the produce and characteristics of all kinds of simulation signal.2. The curve fitting theory based on 2-dof are deduced to make it can fit the adjacent two peaks of inter-blade-coupling vibration at the same time. And the regression method and sine fitting method based on 2-dof are used to identify inter-blade-coupling vibration parameters. Then use the simulation data to validate this two kinds of blade Tip-Timing algorithm, the results show that identification of vibration parameters and simulation parameters setting are basically the same.3. Develop a set of inter-blade-coupling vibration parameters identification software based on Matlab. A lot of simulation is carried out to verify the software, the result is correct. It has friendly interface, programming norms, complemented by a wealth of mouse and keyboard control, achieved the humane operation.