This paper presents the testing and measuring method of three kinds of flow instability test(rotating stall and surge)

the test results and analysis of them for a turbojet engine with "clean" or distorted inlet flow. The tests have been carriedout as follows. ( 1 )testing of the"upper"and"lower"stall-point on the stall line of the engine with and without distorted inlet flow; ( 2 )tests of surge in the engine with "clean" or distorted inlet flow at n= 1.0

0.933

0.9

0.87 and with rated Anb (area of first-stage turbine nozzle) or Anb decreased by 12%; (3)tests of static-forced surge(decreasing the area of engine nozzle very very slowly)and dynamic-forced surge for an engine with"clean" or distorted inlet flow. The results from the tests comprise.