Development of a one-dimensional code for the initial design of a micro gas turbine mixed flow compressor stage

Abstract The use of micro gas turbines (MGTs) for once-off and unique applications means that a rapid turnaround design process is required. The development of a MATLAB® application-based program for the initial design and performance analysis of radial and mixed flow compressors is discussed. The program code is based on one dimensional (1D) mean line flow and loss model theory. For verification, 18 test compressors were developed, covering a wide range of design velocities, mass flow rates and meridional exit angles. Predicted performance results were verified using Numeca/FINE™ Turbo software. Initial comparisons between 1D and Computational Fluid Dynamics (CFD) results did not match well. The 1D software over-predicted compressor performance and provided poor choke prediction. Consequently, empirical models to correct these deviations were derived and implemented into the 1D Application code. The updated 1D code provided a mean choke prediction difference of 1.59% compared to an initial 14.98% difference at the design point. Mean total-to-total isentropic efficiency and pressure ratio reduced to differences of 0.74 and 1.24% from values of 11.23 and 9.31% respectively.