Intelligence design method for three-dimensional vaned diffusers in a centrifugal compressor

Abstract

This paper presents a multi-objective optimization-based intelligence design method for the design of the three-dimensional vaned diffuser for a given centrifugal compressor. This design method consists of three-dimensional vaned diffuser design model and its solving strategy. The three-dimensional vaned diffuser design model consists of the diffuser geometry mathematical model, performance evaluation model, objective equation, and design space. The diffuser geometry is described by the mathematical model of the meridional configurations and vane camber, trailing edge lean, and thickness. The generic design space is determined through literature statistical investigation. An NSGA-II multi-objective optimization algorithm, utilized to solve the three-dimensional vaned diffuser design model, directs the diffuser geometry variables to achieve the maximum stage isentropic efficiency and static pressure ratio at the design point within the design space automatically and intelligently. The presented three-dimensional vaned diffuser design method is demonstrated using a case test for a centrifugal impeller. The convergence of evolutionary solving for this three-dimensional vaned diffuser model is analyzed in detail, which provides the convergence reference for engineering applications. Three representative three-dimensional vaned diffusers on Pareto front are utilized to check the diversity of geometry shape and overall range performance characteristics. The results show that the three-dimensional vaned diffuser design method established here has excellent potential in automated design and maximizing stage performance. The method reported here could provide a valuable reference for the intelligent design of radial turbomachinery diffusers.