This report presents a conceptual design of axial flow gas turbines for helium-cooled reactors. The reference design for the gas turbine system is adopted from the MPBR project of MIT, which uses an indirect helium/helium cycle. The purpose of this study is as follows: to develop the conceptual design tools for gas turbines, to validate an verify them comparing with the MIT design, to draw the off-design characteristics of the gas turbines, to do scaling analysis for scale-down gas turbines using the validated design tools.
In the reference design, the gas turbine system consists of three-shaft configuration. This report describes the conceptual design of the high-pressure compressor, the high-pressure turbine and the power turbine, and the scaling analysis of these gas turbines by the mean-line design and the meridional flow analysis method. It was found out that the high-pressure compressor, the high-pressure turbine, and the power turbine consist of 8 stages, 4 stages, and 14 stages, respectively. After completion of the stage design, the design point performance and the off-design characteristics of the gas turbines were estimated. Also the fluid properties were calculated through the gas turbines in the axial directions.
This report shows that the conceptual design tools are capable of predicting design point performance within ±1% compared with the reference. And the results of the scaling analysis indicate that the effects of the non-dimensional mass flow and the non-dimensional speed are stronger than the effect of the Reynolds number in subsonic flow.