Medium-high Temperature Measurement Technology Research Based On The Metal AC Susceptibility

Engine is the core part of the aircraft.It is an important symbol of the country's level of industry and the area domain.The temperature detection of the engine combustor is the key element for improving the performance of the aircraft turbine engine,as well as one of the main bottlenecks the next generation engine revolution will face.However,currently the technology has a great deal of research gap and so the thesis will study on high temperature measurement technology of the turbine engine combustors,and creatively present an innovative magnetic solutions for temperature measurement.At present,the main techniques of temperature measurement are thermocouple measurements,optical pyrometer thermometry,radiation and so on.But they have the problems of time lag,high cost and low precision and being unable to meet the real time,high precision need of 2000? combustion chamber temperature measurement.On the basis of existing research about magnetic temperature measurement,the thesis studies temperature measurement model of AC susceptibility,proposes a temperature management theory of Eddy current effect on the base of Brown relaxation and Debye theory,and designs a metal AC susceptibility measurement device and temperature control system with high precision and response time being less than 1 second.The thesis also made multiple experiments to the system.The metal AC susceptibility measurement system consists of three main parts: the generation of exciting magnetic field,the measurement of response field and the processing of data.From the point of view of stability,noise reduction,the hardware system uses the Helmholtz coil to generate a stable and uniform excitation magnetic field and the front differential amplifier to realize the weak signal detection.At the same time,the system implements the DPSD filtering algorithm and PID control on LabVIEW software platform.The thesis chooses Tungsten and Alloy as the testing sample and designs the cooling experiment of metal AC susceptibility,studies temperature characteristics of ac magnetic susceptibility of metals from 0-1000 degree.In addition,in order to solve the unmeasurable problem of temperature like Tungsten,the thesis gives a solution of heat resistance temperature coefficient calibration.Analysis of experimental results is available: metal's AC susceptibility has temperature-sensitive properties under high frequency excitation,which means it has some relationship with the temperature.The experiment of cooling metal verifies that the magnetic susceptibility AC susceptibility testing system is stable and accurate.It certifies initially the possibility of applying the Eddy current to the temperature measurement of engine combustion chamber.It provides the theoretical basis and value for non-contact high temperature measurement.In the end,the thesis discusses the optimization of the system.It analyses the influence of effects factors such as eddy effects of detection coils on the temperature management of metal AC susceptibility and gives reasonable solutions from the hardware and software.It provides a theoretical basis for further optimizing the susceptibility measurement model and improving the response speed and precision of the system.