Simulation And Experimental Research On Non-Contact Measurement Of Mistuned Blades Vibration

The blade is the core component of large rotating equipments such as aero engine,flue gas turbine,steam turbine,blower,gas turbine and so on.It is an important guarantee for the normal,safe and efficient operation of the equipments.As the rotating blades work in the harsh conditions such as high speed,high temperature,high pressure and high load,also they are affected by many kinds of forces,for example: the centrifugal force,airflow,exciting force,bending stress and other forces.Over time the blades will be prone to fatigue failure,directly damage to safe operation of large rotating equipments,resulting in huge economic losses.Therefore,it is necessary to monitor the working states of the rotating blades in real time.The non-contact measurement of mistuned blades vibration is mainly studied in the following three aspects by this paper:(1)Use cyclic symmetry analysis and mobile interface modal integrated super-element method respectively to simulate the static frequency,dynamic frequency and each pitch vibration mode of the harmonious blade disk system by ANSYS.Verify that mobile interface modal integrated super-element method has high analysis accuracy by comparing the simulation results of two methods.Then use the super-element method to simulate the vibration modes of the mistuned blade disk system and find out its vibration laws.(2)Use SIMULINK in MATLAB to build blade tip-timing vibration measurement system model graph.Simulate the synchronous vibration signals of blades under constant speed and variable speed sweep.Then use the synchronous vibration parameter identification algorithm to identify the synchronous vibration signals of blades with assumed parameters and obtain the identified vibration parameters.Then verify that the algorithm has high identification precision by comparing the identified parameters with the assumed parameters.(3)Make some experimental measurements for the vibration of the mistuned blades.Set up a test platform,use resonance method and blade tip-timing method to measure the vibrations of mistuned blades.Use the synchronous vibration parameter identification algorithm to reconstruct the vibration signals of mistuned blades measured by the experiment.Then compare the vibration parameters after reconstructions with those of the blades obtained by ANSYS and MATLAB simulation.It shows that the calculation results of the two simulation softwares are accurate and reliable.