| Cycling parameters of aero-engines is continuously improving due to the higher requirements of modern aircraft to propelling system.The working environment of aero-engine hot-end components deteriorates resulted from higher turbine inlet temperature,and application research of efficient cooling technology faces with great challenges such as accurate measurement of small cooling gas flow rate.At present,the accuracy and reliability of small gas flow rate measurement equipment cannot meet the demand of aero-engine research as a result of wide range of gas flow parameters in aero-engines.In a word,it is very important to build appropriate flow standard equipment,explore advanced small gas flow measurement methods,and to improve the accuracy of small flow rate measurement equipment for aero-engines.A set of high-accuracy calibration equipment applied to small flow rate measurement,which is based on laminar flow principle,was established according to turbine blade cooling gas flow characteristics of small and medium sized aero-engines.The uncertainty of the equipment is about 0.2% RGD.The design methods of small gas flow rate measurement equipment were studied by numerical simulations.The flow field of different types of small gas flow rate measurement equipment was analyzed using Fluent and the influence laws of key parameters such as core length,core diameter,entry and exit cone angle on the flow rate characteristics were studied.Two sets of small gas flow measurement equipment with better structure have been manufactured and calibrated by measuring the flow static pressure and flow rate along the flow direction.This equipment was applied to a real turbine blade cooling tests,and the measured blade cooling effect value is about 0.235,which is a little smaller than the calculated value 0.258,but the error is within the range of engineering application. |
