Numerical Investigation of the Effect of Design Parameters on the Blade Flutterr Prediction

Blade flutter is one of the major problems that designers of modern gas-turbine engines face. As a rule, the flutter of compressor blades is predicted using simplified criteria devised in design organizations based on the experience of designing and refining engines. In this paper a study of the influence of the design parameters on prediction of blade flutter in compressors of gas-turbine engines is presented. Empirical and probabilistic criteria are not applicable to evaluation of the flutter since the parameters in question are not among the decisive parameters for simplified criteria. In this work, a numerical algorithm for prediction of the flutter based on the energy method is used. The algorithm is applicable if the oscillation modes in vacuum are close to the corresponding modes in a flow, a condition that is always met for compressor blades, with the exception of rarely used hollow blades and blades of composite materials. It is shown that the inter-blade tension has a significant influence on the flutter boundaries, while the effect of other design parameters under investigation on the flutter boundaries is insignificant.