Study on Turbine Blade Fractures of Some Cooling Turbine

摘要

Turbine blade fractures of some cooling turbine was analyzed and judged to be incurred by high-cycle fatigue. Through using the finite element method, the natural frequencies of its blades were analyzed, and their natural frequencies of the first 20 orders were obtained under the action of centrifugal load. The computational fluid dynamics simulation was used to identify the unsteady aerodynamic load applied on the blade under the typical conditions. The fast fourier transform was carried out to identify the main frequency of the unsteady aerodynamic load. A Campbell diagram analysis was carried out so as to show that blade resonance occurs to the turbine impeller wheel if its speed is at 55000r/min or 72000r/min. Resonance points can be effectively evaded if the structures of the blades are improved to dramatically increase their natural frequencies. The test result proves that the improvement measures are effective.