1D numerical correction for temperature measurement with inclined thermocouples

Thermocouple bead temperature, i.e., thermocouple measurement temperature, is usually not equal to the gas temperature due to the complicated heat transfer of the bead. The 1D numerical method, used to correct this measurement error, solves the energy conservation equations of the thermocouple numerically. During the process, the convection coefficient between the thermocouple wires and the incoming flow is needed. However, the current correlations for the convection coefficient of the wires are not accurate when the wire pitch angles are varied, which will affect the correction accuracy. CFD simulations are carried out, and the data are used to fit a correlation for the convection coefficient of the wires with different pitch angles. Compared with the CFD data, the correlation has errors between -15.96% and 20.96%. The correlation is then used in the 1D numerical program to obtain the corrected temperature for the experiment of the P10R- 010 and P10R-020 thermocouples measuring the Hencken H2/air diffusion flame. The errors between the corrected and real gas temperatures are between -11 K and 24 K. Considering the experimental error is 35 K, the correlation generates very good prediction accuracy with the 1D program.