Abstract: The present application provides an exhaust frame differential cooling system of a gas turbine engine to mitigate a temperature differential along a compressor and/or a turbine to minimize centerline eccentricity of a shaft. The exhaust frame differential cooling system may include a number of compressor temperature sensors positioned about the compressor and/or a number of turbine temperature sensors positioned about the turbine, an exhaust frame including an inner barrel with a bearing tunnel for the shaft, an outer barrel, and a number of struts extending from the inner barrel to the outer barrel, a blower, and a cooling air metering system that provides cooling air from the blower to the bearing tunnel and through the inner barrel, the struts, and the outer barrel in response to the temperature differential being determined along the compressor and/or the turbine.

Abstract: The present application provides an exhaust frame differential cooling system of a gas turbine engine to mitigate a temperature differential along a compressor and/or a turbine to minimize centerline eccentricity of a shaft. The exhaust frame differential cooling system may include a number of compressor temperature sensors positioned about the compressor and/or a number of turbine temperature sensors positioned about the turbine, an exhaust frame including an inner barrel with a bearing tunnel for the shaft, an outer barrel, and a number of struts extending from the inner barrel to the outer barrel, a blower, and a cooling air metering system that provides cooling air from the blower to the bearing tunnel and through the inner barrel, the struts, and the outer barrel in response to the temperature differential being determined along the compressor and/or the turbine.

Abstract: This application provides a temperature gradient control system for a double wall casing of a compressor. The double wall casing may include an inner casing and an outer casing such that a flow of air is pulled through the double wall casing. The temperature gradient control system may include upper discharge piping with an upper modulation valve and a lower discharge piping with a lower modulation valve. The upper modulation valve and/or the lower modulation valve modulate the flow air pulled through the double wall casing to reduce a temperature gradient across the outer casing.