The experimental investigation of an unsteady flow pattern in the models stages of various purpose for the compressor assemblies of modern turbofans has revealed, when approaching the surge line, a physical phenomenon which is characterized by: 1) forming, as a result of separation, of a non-uniformity of the circumferential flow rotating together with the wheel;2) redistribution of pulsation energy with the decrease of the air flow to the frequency band Df = 0-fwh Zwh. The symptom hasbeen obtained and proposed for early diagnostics of the approaching surge threshold.
|
