Research Of Turbine Blade Tip Clearance Monitoring Technology

In recent years,with the continuous development of gas turbine related technology,gas turbine has been widely used in power industry,aviation field,ship power and other fields.The size of the tip gap directly affects the efficiency and operational safety of the gas turbine and is an important parameter in evaluating the performance of the gas turbine,tip clearance measurement technology has gradually become a hot research at home and abroad.Through the analysis and comparison of various methods of measuring the tip clearance at home and abroad,this paper chooses the measurement technology based on capacitance method to carry on the related research.This method can be adapted to the high temperature and high pressure of the gas turbine working environment and has a high anti-pollution ability,can achieve continuous measurement of the tip gap.Capacitive blade tip gap monitoring system consists of capacitance sensor,capacitor signal processing module,data acquisition module,signal processing software platform,monitor and so on.The capacitance sensor converts the change of the tip clearance into a change in capacitance.The capacitive signal processing circuit converts the capacitive signal into a measurable voltage signal and outputs it.Finally,through the signal acquisition and processing to achieve the tip of the gap measurement and display through the PC.The main work is as follows:(1)the capacitance sensor and cable with high temperature resistance are designed and made.A signal processing scheme based on carrier frequency tracking principle is designed for the problem of stray capacitance interference in complex working environment of gas turbine,and its feasibility is verified by theoretical analysis.(2)The dynamic test platform based on touch screen and PLC control is designed,and the simulated blade is designed by SolidWorks software,which provides the basis for real-time measurement of blade tip gap and related research.(3)The high speed acquisition,data processing and related algorithm design of the hardware output voltage signal of the measurement system are completed,and a real-time blade clearance measurement software system is prepared based on LabVIEW software.(4)The factors affecting the accuracy of the tip clearance are studied on the dynamic simulation blade test platform.Aiming at the measurement error caused by the error of bladethickness,a measurement scheme of laser distance measuring sensor and capacitive tip clearance measurement system is designed.Through a large number of experiments and related research,this paper designed the tip clearance monitoring software system measurement accuracy,blade segmentation is accurate,with strong stability and reliability.Combined with the front-end capacitive sensor and capacitive signal processing module,real-time measurement of the tip clearance is realized on the dynamic experimental platform.