Nondimensional Compressor Performance for a Range of Mach Numbers and Molecular Weights

The performance of centrifugal compressors is analyzed on the basis of nondimensional pressure and impeller-exit flow coefficients ψ and ϕ₂. Use of these coefficients for impellers of high solidity permits presentation of compressor performance in a single curve for all conditions up to a critical Mach number. To show compressor data in a characteristic family of curves, performance is represented by pressure and flow coefficients K_P and K_Q. These coefficients take into account the coefficient of compression and the molecular weight simultaneously with the induction temperature. Test data for two compressors are presented over a range of Mach numbers from 0.36 to 2.0, and molecular weights in the range of that of air to heavy refrigerants. The test data show experimental verification of the fact that for centrifugal turbomachines with blades of high solidity the performance is a function of the Mach number only.