STP520: Fatigue of Protective Metal Oxides in Combustion Chamber Exhaust Gases

    Dils, RR
    Senior research associate, Materials Engineering and Research Laboratory, Pratt & Whitney Aircraft, Middletown, Conn.

    Pages: 10    Published: Jan 1973


    Abstract

    An analysis of the oxidation of an aluminized nickel-base alloy in the exhaust gases of a gas turbine main burner has been developed. Characterizations of combustion chamber exhaust gases and the temperature fluctuations induced at fireside surfaces by the exhaust gases are reviewed, and the analyses are applied to the description and simulation of the exhaust gases of a gas turbine main burner. The results of wide bandwidth gas temperature measurements at the entrance to the turbine section of a large gas turbine are used to obtain metalmetal oxide interface temperature waves at the surface of the turbine components. Simulations of the interface temperature wave in exhaust gases of laboratory combustion chambers and oxidation experiments in the laboratory combustor exhaust gases are presented. It is shown that the small fluctuations induced at the surface of the turbine components by the main burner exhaust gases can be of sufficient amplitude to affect the rate of oxidation of the turbine components. The example temperature fluctuations measured in the gas turbine cause the growth of a porous nonprotective oxide on the surface of the aluminized nickel-base alloy. A continual loss of the oxide results in a significant increase in the rate of oxidation of the material.

    Keywords:

    fatigue (materials), thermal stresses, nickel alloys, oxidation, turbine components, shear properties, interfaces


    Paper ID: STP38832S

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP38832S


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