Analytical Study of Matching of Dual Compressor Modules With Turbine for Small Modular Reactors

Abstract An analytical study of a power conversion unit consisting of a dual compressor and a turbine operating on a closed Brayton cycle with helium is presented. The turbomachinery was a constant hub design with two compressor modules and a turbine module. The design code included the capability to perform sweeps of input parameters such as the polytropic efficiency or loss coefficient, degree of reaction, etc. It is required that the pressure rise of each of the two compressor modules be approximately equal. An optimization procedure for the low- and high-pressure compressors resulted in both of them having seven stages. The performance for each of the compressor stages is almost identical. Another optimization procedure for the turbine yielded six stages. Likewise, the performance for each of the turbine stages is almost identical. Performance maps were developed individually for each of the compressor modules and the turbine. Mathematical constraints based on problem physics were used in conjunction with the component maps to trace turbomachinery operating points. Results show that the low-pressure compressor operates close to the surge line. It is recommended to implement a recirculation path to avoid possible surge in compressor.