热电偶非稳态测温误差特性一维分析

To reveal the influence mechanism of temperature measurement error of thermocouple under unsteady operating conditions， one-dimensional unsteady calculation model of temperature measurement of thermocouple was established. A comprehensive evaluation was conducted to reveal the influence of different installation structures， bonding materials and surface heat transfer coefficient conditions on the unsteady temperature measurement error for the thermocouple. The influence of Biot number on unsteady temperature measurement was further explored. Results showed that it is necessary to consider environmental radiation effect. Temperature error was 1.48 K at 300 s temperature measurement time compared with that without consideration of environmental radiation effect. Different installation structures of thermocouple had a greater impact on the temperature measurement error，with a maximum measurement temperature difference of 1.85 K. Moreover，the greater thermal conductivity of the bonding material indicated，the smaller temperature measurement error in the stage of unsteady regular status，and the absolute error was less than 0.5 K after 150 s temperature measurement time. Especially，the surface heat transfer coefficient played an important role in the unsteady temperature measurement error. The larger surface heat transfer coefficient indicated the greater temperature measurement error due to initial temperature field. When the thermal conductivity of bonding material was 2.4 W/(m·K)， the variation range of temperature measurement error within the surface heat transfer coefficient range of 50− 250 W/(m²·K) was 0.2− 0.5 K. Therefore， the research results can provide a reference for the unsteady measurement of wall temperature in the heat transfer experiments of aero-engine.