Numerical Turbine Blade Fatigue Life Analysis for Reusable Liquid Rocket Engines (LREs) Applications

Abstract

Nowadays reusability of LREs, represented in projects such as CALLISTO and Maїa (both including the re-usable Prometheus engine), is seen not only as essential in the effort to prepare competitive future European space access, but also sets a new requirement towards high reliability engineering standards. With engine operation life in excess of a single mission, it is necessary to evaluate the most critical components, which could develop cracks as in case of the e.g. the turbopump turbine BLISK (Blade Integrated Disk) and, as a result, lower the total engine flight life. Within our research we focus on the turbine blade analysis for reusable LRE applications including high cycle fatigue (HCF) and low cycle fatigue (LCF). Turbine blades are subjected to large thermo-mechanical cyclic strains arising from the high temperatures driving gas in combination with a fast start-up sequence as well as high rotational speed – crucial for obtaining high performance and structural mass efficiency for LREs. To predict the turbine blade fatigue life, we compare an analytical (0D) and numerical (3D FE) approach for a selected test case. The fatigue life analysis evaluates the BLISK at the highest loading condition accounting for HCF by a modified Goodman approach.