Efficiency optimized axial flow compressor stage with a given shape of flow-path

Performance improvement and optimization for Brayton cycle plants include mainly two aspects: one concerns thermodynamic cycle parameters, another concerns component parameters. As one aspect of the power plant optimizations, parameter optimization is an important design practice for performance improvement of axial flow compressor stage (AFCS). Stagnation isentropic efficiency (IEFF) optimization of AFCS is studied preliminarily by using 1-D flow theory. Optimization design model of AFCS with a given shape of flow-path is provided. Five parameters are taken as design variables, including absolute exit and inlet angles of rotor, absolute exit angle of stator, and relative air densities at exit and inlet stations of stator. Energy balance equations for 1-D flow are constraints. Analytical relations about stagnation IEFF and design variables of the AFCS are obtained. Numerical calculations are performed for a constant mean-diameter AFCS. The results illustrate influences of various fixed design parameters on the optimum stagnation IEFF of the AFCS. The results illustrate that optimal stagnation IEFFs with three fixed input parameter combinations of work coefficient and flow coefficient increase 0.78%, 5.15%, and 5.66% than that of reference plan, respectively; optimal stagnation IEFFs increases with increase of work coefficient and decrease of flow coefficient.