Application of in situ oxidation-resistant coating technology to a home-made 100 kW class gas turbine and its performance analysis

Abstract

Abstract An axial type 100 kW class gas turbine power generation system equipped with an additive supply system was fabricated and tested for the performance evaluation experimentally and analytically, in order to confirm the advantage of in situ oxidation-resistant coatings on gas turbine components toward the performance of a gas turbine power generation system directly. The gas turbine was operated up to the rated speed of 74,000 rpm, and to the turbine inlet temperature (TIT) of ∼1200 °C. At the early stage of this test operation, an oxide film precursor (tetraethylorthosilicate/methanol mixture, 10 vol.%) was fed into the combustion chamber by the additive supply system to in situ deposit silica based layers and thus to protect the metallic components from hot combustion gas during operation. After the test operation, in situ deposited silica layers were observed on the surface of the combustion chamber, turbine nozzles and rotor blade. Due to these protective layers the gas turbine could be harmless tested at TIT = 950 °C, much higher than its design temperature of 850 °C. According to the performance analysis, a TIT increase of 100 °C was expected to be accompanied by ∼5% increase in the turbine rotation speed by consuming more fuel and air by 22% and 8%, respectively. As a result, the power output increased by 42% and the thermal efficiency from 12% to 14%. This result was well accorded with that of empirically obtained, indicating that no noticeable impacts on the performance due to in situ deposited layers on the components.