Recession Rate Prediction for Ceramic Materials in Combustion Gas Flow

Abstract

The influence of various basic factors of combustion gas flow conditions on the recession rate of silicon nitride, silicon carbide, and alumina has been experimentally clarified, and the recession rate equation is deduced using the dependence of influential factors on the recession rate and the mass transfer theory. The exposure tests are performed under various gas flow conditions (T = 1100–1500 °C, P = 0.3–0.7 MPa, V = 40–250 m/s, PH20 = 30–120 kPa, PO2 = 20–45 kPa). Recession rates mainly depend on water-vapor partial pressure, pressure, gas temperature, and Reynolds number in the gas flow conditions inside the specimen holder. The dependent on oxygen partial pressure is extremely low for silicon nitride and silicon carbide. The recession rates of silicon nitride, silicon carbide, and alumina in combustion gas flow are expressed in the form exp(−E/RT)·(PH20)n· Re0–8/P, and the predicted recession rates of silicon nitride shows good agreement with reported exposure test results under gas turbine conditions.