Plume temperature measurement of a solid propellant rocket engine using multispectral thermometry

The temperature of a high temperature, high pressure plume solid propellant rocket engine is difficult to measure but is useful for determining the combustion status of the engine. The plume temperature of a mounted solid propellant rocket engine was measured by a 6-target 8-wavelength pyrometer in this paper. The processing of the multispectral thermometric data was based on the relationship between the emissivity and the wavelength of the plume as predicted by a BP neural network. The true temperatures were then predicted using auto-regression of known emissivity data. The experimental results showed that the calculated temperatures were within ±100 K of the temperatures provided by the rocket engine designer. Therefore, multispectral thermometry is a practical method for measuring the plume temperature of solid propellant rocket engines.