METHOD OF AEROACOUSTIC TESTING OF THROUGH PART OF AVIATION GAS-TURBINE ENGINE Russian patent published in 1995 - IPC

FIELD: measurement technology. SUBSTANCE: air feed source - fan 3 is started and brought into "cold engine motoring" mode. Tested unit of combustion chamber 1 is blown. Microphone 5 is shifted along the periphery of output section 4 and levels of sound pressure of aerodynamic noise are measured periodically through all the range of sonic frequency spectrum. Microphone 5 may takes different places 11 along the peripheral part of section 4 keeping strong direction to axis of unit of chamber 1, and is situated at the same distance from output section 4. Values of measurements are converted by microphone 5 into levels of sonic pressure of aerodynamic noise in spectrum analyzer 6. After each measurement is made, the values measured have to be compared with standard values of serviceable unit of chamber 1 in comparator 7; these values are generated in comparator 7 from the first checking element 8. If at all the measurements the values of levels of sonic pressure measured coincide with standard ones with sufficient precision, signal "unit of combustion chamber is serviceable" is applied to registrar 10. EFFECT: improved precision. 1 dwg