Surrogate-assisted Multi-component Aerodynamic Optimization of Centrifugal Compressor Towards Performance Improvement of Adaptive Cycle Engine

Centrifugal compressors are widely used in gas turbines, so it’s important to have an efficient performance; also, optimizing this part can affect the whole engine’s performance. Adaptive Cycle Engines (ACEs) are a group of gas turbine engines that can change key aerodynamic parameters such as pressure and bypass ratio through geometric structure adjustment. In the present research, the ACE with a centrifugal compressor as its high-pressure compressor (HPC) is investigated, and the aim is to improve the engine performance through compressor optimization. A three-dimensional surrogate-assisted aerodynamic optimization method is applied to maximize the isentropic efficiency of the centrifugal compressor with a constraint on the total pressure ratio. The optimization results show a 3.4% improvement in the design point efficiency, a 1.4% increment of the choked mass flow rate, and a wider operating range is obtained. Afterward, thermodynamic modeling of the engine performance is used to calculate the engine characteristics before and after the optimization. 3D performance maps of the compressor and fan, calculated by CFD simulation, are used for accurate engine performance modeling. The final results of the engine performance show a reduction of 2.0% in the specific fuel consumption of the improved engine, which is an important achievement in these engines.