A method of measuring 2D flow-field at rotor exits of transonic multistage compressor

In order to obtain the key flow-parameters which are urgently demanded in small axial-compressor design, a method of measuring inter-stage unsteady flow-field in a small axial-compressor with a single-hole fast-response cylindrical-probe has been developed. The measuring method was based on the characteristics of flow around cylinder. Utilizing phase-locked technique, the inter-stage flow-field measurement was realized by rotating the probe at several angular positions. The interpolation and fitting method were used to process the test data. In this way, the inter-stage 2D steady flow-field was obtained. The error analysis shows that this probe possesses adequate measuring precision, in which the error of the yaw angle is less than 1.8° and the uncertainty of Mach number, total pressure and static pressure is, respectively, 3.4%, 0.94% and 3%. Then, the unsteady measurement technique of fast-response pressure probe was applied to an experimental investigation in a small three-stage transonic axial-compressor. The measurement results indicate that the total pressure and Mach number are obviously lower within 85%~100% span than those at lower half span, which leads to flow overturning. These results provide the key flow distribution for the optimization of inter-stage matching. Therefore, it verifies the engineering application of this fast-response pressure probe measuring technique.