Aerodynamic design and strength check of a two-stage dual-rotor opposed centrifugal compressor

Abstract

[Objectives] To accomplish the design of a two-stage dual-rotor opposed centrifugal compressor for a small gas turbine,[Methods] the compressor is subject to aerodynamic design and three-dimensional flow field check by using the software Concepts NREC and the Numeca. The impeller is made of 0Cr17Ni4Cu4Nb. The strength and vibration characteristics of the centrifugal impeller are analyzed and checked with the ANSYS within the linear elasticity range.[Results] The aerodynamic design results show that the total pressure ratio of the two-stage centrifugal compressor at design mass flow rate is 7.97,the adiabatic efficiency is 80.39% and the stability margin is 17.2%. The results of strength and vibration analysis show that the impeller strength meets material strength requirements. According to the "triple point" resonance theory,there are no risks of resonance vibration for the two-stage centrifugal impellers.[Conclusions] A design scheme for the two-stage centrifugal compressor with high pressure ratio,high efficiency and wide stability margin is obtained,the compressor meeting the requirements for aerodynamics,strength and vibration,which can provide some fundamental support for the design, technology integration and test of a small gas turbine.

Keywords

• two-stage centrifugal compressor
• aerodynamic design
• strength analysis
• numerical simulation