Ignition and surface temperatures of double base propellants at low pressures. II - Comparison of optical and thermocouple techniques

The two most popular temperature measurement techniques for solid-propellant research, infrared and thermocouple, are compared on the basis of experiments involving the simultaneous use of both techniques. It is found that the fine-wire thermocouple measurements are more reliable than the optical measurements, and that temperature measurements at the burning surface are subject to error with both techniques, on account of the gaseous products of the solid decomposition. An analytical solution for the preignition warmup under external radiation is also included, in addition to a numerical technique for computing the infrared emission from a finite depth of propellant under steady burning.