Estimation of Surface Temperature and Heat Flux Using Embedded Thermocouples

This thesis investigates several new methods for estimating surface temperature and heat flux based on thermocouples embedded within the interior of a test article. The test apparatus was a Mach 2 axisymmetric rocket nozzle with probes embedded at depths of 1/8” and 1/4” from the inner surface of the nozzle at the throat and exit locations. Three methods for numerically estimating temperature and heat flux at the surface of the nozzle were considered: a one-thermocouple slab-coordinate method, a two-thermocouple slabcoordinate method, and a finite-element analysis (FEA) based on a one-dimensional cylindrical coordinate method. Comparisons between the methods, as well as temperature and heat flux uncertainties caused by the axial location of the thermocouple probes (and resulting radius of curvature of the nozzle materials considerations), are presented. The slab-coordinate two-thermocouple and FEA methods show good agreement in both thermocouple probe axial locations, but the one-thermocouple measurement showed significant uncertainty for the throat location, but offered good agreement at the exit location. Suggestions are made for future improvements in experimentation and analysis methods.