Functional Validation of K-Type (NiCr-NiMn) Thin Film Thermocouple on Low Pressure Turbine Nozzle Guide Vane (LPT NGV) of Gas Turbine Engine

This study presents a concerted approach developed for experimental measurement of surface temperature of critical aeroengine components using a non non-intrusive sensor that is compatible with structural integrity and endurance requirements of high temperature environments. Contrary to wire type thermocouples that cause structural degradation and aerodynamic disturbance in the flow path, the present study proposes a thin film thermocouple (TFTC) that is deposited using electron beam (E-beam) evaporation process. The basic experimentation and proof-of-concept studies are carried out to suit the deposition of K-Type TFTC on a turbine nozzle guide vane that is made of nickel based super alloy. The performance of TFTC is compared to that of wire type thermocouples. The Seebeck co-efficient of the developed K-Type TFTC is found to be 42 μV/°C, with a time constant and drift of 1.11784 ms and 0.4 °C/hour respectively. Based on the feasibility studies and characterization results of prototype TFTC, the deposition of similar TFTC was carried out on low pressure turbine nozzle guide vane (LPT NGV) of an aeroengine using same optimized parameters and procedures. The results presented vindicate the application of the proposed methodology for a developmental aero gas turbine engine.