Turbine Housing Design Optimization and Qualification Rig for High Temperatures 2002-01-0851

New engine trends of higher exhaust temperature driven by retarded fuel timing to reduce NOX emissions and by increased power requirements, will likely cause turbine housings to see heavier thermal transient loads and, as a results, greater likelihood of cracks. New innovative housing designs and qualification methods are needed to prevent thermal-mechanical cracking and to provide successful design validation. The purpose of this paper is to outline a successful new design and qualification procedure of turbine housing subjected to various duty cycles in the field. Both analytical and experimental techniques are adopted in this work. Results of the analytical model were correlated to the experimental measurements for model verification. Analytical transient FEA analysis was utilized to understand the effect of thermal loading on the turbine housing. The model was calibrated against engine measurement during engine cyclic testing. After calibration the model is used to optimize the housing design. New housing design concepts are proposed. The new housing design concept is superior by at least 2.5 times increase in life compared to the traditional baseline design.

A new process to develop a qualification rig test, which reflects various engine duty cycles, is outlined. Qualification test development involved the development of a successful endurance rig test that replicates field failures. Therefore, it was necessary to conduct thermal and strain measurements on a running engine. These measurements were utilized to design simplified test conditions that signify the influence of the critical operating parameters contributing to the failures. The process was very successful in qualifying superior designs with significant life improvements. An accelerated dual turbo gas stand endurance test and test procedure was thus developed and the cycle time was shortened.