No abstract

This paper presents the results of an EPRI sponsored test program to determine the extent and chemical makeup of turbine inlet nozzle guide vane surface deposition resulting from extended exposure to contaminated combustion gas. Testing was accomplished in a three-vane cascade facility at a nominal gas temperature level of 1365°. Over the course of the test, the cascade was operated at fixed coolant feed pressure and expansion ratios consistent with engine conditions. The test vanes represented existing hardware featuring porous wall skin cooling. Testing was terminated after 96 h when pressure surface deposits became sufficiently great to significantly alter passage aerodynamics. Key findings included the observation that vane deposition was confined to the airfoil pressure surface and that, despite progressive blockage of cooling air flow, time averaged pressure surface metal temperature levels actually decreased over the course of the test.