Method for judging journal sticking of low-pressure rotor of small-bypass-ratio aero-engine

The invention belongs to the field of aero-engine design, and relates to a method for judging the journal sticking of a low-pressure rotor of a small-bypass-ratio aero-engine, which comprises the following steps of: firstly, performing an engine starting test, determining the rotating speed NH of a corresponding high-pressure rotor when the low-pressure rotor has a stable rotating speed, and further determining the relative conversion rotating speed nHRD of the journal sticking; then the engine is controlled to work according to the set high-pressure rotor rotating speed rising rate, and the corresponding actual journal sticking conversion rotating speed nHRD actual under the different high-pressure rotor rotating speed rising rates is obtained; according to the method, criteria of complete clamping stagnation and incomplete clamping stagnation of a rotor are set and put into an engine starting test for verification, if verification succeeds, the criteria are effective, and the two criteria are written into a