Error of Thermocouple in Measuring Surface Temperature of Blade With Cooling Film

A new method is proposed for reducing the error of thermocouples in measuring the surface temperature of blades with cooling film. Both the measurement error and the conduction error of film cooling blade surface temperature were numerically investigated. Benefited from the optimized thermocouple fixation mode, the temperature measurement error can be reduced by 40% at least. The temperature measurement errors of surface fixed model and groove fixed model were analyzed and compared. Furthermore, the effects of different head gaps, film thickness and film temperature on the temperature measurement error are described in detail. Under the optimal parameters, the temperature measurement error of thermocouples can be decreased by 99.5%. Finally, the groove fixed model is studied experimentally and the results show that the temperature measurement error can be reduced by 99.83% under the optimal groove depth, which is in good agreement with the simulation results. This error analysis and reduction method attaches great significance to the improvement in the temperature measurement accuracy of turbine blades, as well as the research of new temperature measurement methods.