Development of a model for determination of preloads on blade shrouds

Abstract

The article presents a digital model for calculating the change in the angles of incidence of compressor rotor wheel blades that characterize tightness. The input parameters for the model are the geometric deviations of the disc slots and blades of the set. The calculation is based on the modeling of joints using the finite element method. To automate the modeling, a parametric design model of the blade created in the CAD module of the NX program is used; a calculation automation program created in the MATLAB environment and an algorithm for converting deformations at points obtained in finite element method into angles. The initial data and the resulting parameter values are stored in spreadsheets. Experimental studies have been carried out, including measurements of the disk and blades of the impeller, their assembly and measurement of interference. A Gaussian filter was applied to process the results of angle measurements. The tightness of the set under consideration was calculated using the developed model. The results showed that the limiting simulation error amounts to 16% of the value of experimental data; the index of correlation between the simulated and experimental data was 0.71.

Keywords

• impeller
• finite element method
• preload
• gaussian filter
• coordinate measurements