Forced Response Prediction: Methodology for the Design of HP Compressors Bladed Disks

Abstract

This paper presents a general approach related to bladed disk forced response prediction and a typical way to use it in the design process. Firstly, a good confidence level in prediction tools must be reached. The first application is a highly instrumented HP compressor blisk representative of a real engine environment. Simulation of forced response is compared to measurements in order to check the accuracy of prediction. For this test case, the results obtained are in very good agreement with measurements. The good quality of prediction is due to the complete characterization performed on the test case: all the influent parameters were identified before testing. But during the design process, many important parameters are unknown and this level of accuracy can not be obtained. Nevertheless, forced response prediction in the early design process can provide interesting information even if uncertainties are high for some parameters. As an illustration, a second application is proposed, based on the design experience of a new HP compressor of a known engine family. Some forced response predictions were performed during development and compared afterwards with measurements obtained during engine testing. This analysis has permitted to confirm some technical choices and to assess the High Cycle Fatigue risk associated to this new engine configuration.