Abstract: The mature model NASA Rotor37 is used to simulate the transition of the compressor’s operation from the steady state to the non-steady state of stall and surge using the simulation software CFX. The transition is analyzed and researched based on the theory of thermodynamics entropy and sample entropy to provide a basis for the fault diagnosis of stall and surge. The two thermodynamic entropy parameters of average specific entropy value and the isentropic efficiency are found by the analysis changing abnormally in the event of stall. The values of the sample entropy obtained by calculation using the static pressure sequence signal at the receiver reach the minimum near the operation point of stall. The goal of providing an important basis for the fault diagnosis of the compressor stall and surge is achieved.

Key words: compressor, thermodynamic entropy, sample entropy, stall, surge, fault diagnosis