Turbine Surface Degradation with Service and Its Effects on Performance

2 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. 3 ABSTRACT This report summarizes work completed over the full three and a half year research effort into turbine roughness. In order to reduce the length of this report the activity from each of the entities represented has been summarized in brief. Thus, the reader is referred previous reports and conference/journal papers referenced in this document that will contain more details concerning this research effort. The objective of this effort is to document the service-related surface degradation of turbine hardware and evaluate the associated losses in performance. During the period of this grant, significant progress was achieved by all of the parties involved. BYU developed a facility capable of producing engine-like deposits in an accelerated format. This has allowed the evaluation of various material systems and synfuels with regard to their rate of deposition and degradation. It also permitted the study of evolving deposits which were then evaluated in a wind tunnel facility using scaled models of the evolved deposits. AFRL has analyzed aircraft engine components from several engine companies and from within the Air Force. A partial summary of their findings is included in this report. UC conducted a series of material system evaluations using a wind tunnel that simulates erosion in a gas turbine. They subsequently correlated erosion to roughness evolution and included this empirical model in their particle-tracking CFD simulations of erosion. Finally, ISU made significant progress with the use of 2D and 3D simulations over turbine roughness structures. The limitations of current 3-D time accurate simulations of roughness were evaluated and new roughness correlations were developed from a series of 2D simulations over …