Development Of Three Target Six Wavelength Pyrometer

The plume temperature of the rocket motor is an important parameter for the characterization of the combustion characteristics of solid propellants, and it plays a key role in the design of missile weapon and launching platform. Because of the characteristics of high temperature, high pressure and strong impact in the plume, the temperature measurement is difficult. According to the requirements of the project, we developed a three-target six-wavelength pyrometer, using multi-spectral thermometry to measure the true temperature and emissivity, temperature measuring range from 900 K to 3000 K, the overall measurement accuracy is better than 3%.This paper mainly completed the development of the pyrometer, including the design of instrument, the development and debugging of the hardware and software system, instrument calibration and testing. The optical system uses the combined prism for beam splitting, which enhances the stability of the system; optical fiber to complete the transfer of light energy between the sampling system and splitting system; detector uses a silicon photodiode to achieve approximately linear output; circuit system adopts the multi-stage amplifier circuit to ensure the whole temperature range sufficient signal-to-noise ratio; finally, the high-speed data acquisition card realizes the signal fast acquisition. The software is programming by C#, with the ADO.NET database access technology, realizes the management and the operation of the data. According to the project requirements, the programming and debugging of the software are completed, including the calibration, measurement and data processing. Finally, we finish the calibration experiment of the pyrometer, including pyrometer wavelength function(PWF) calibration and temperature calibration, then verification and testing the pyrometer.This pyrometer has three sets of optical sampling system, optical fiber transmission, prism beam-splitting system and multi-stage amplifier circuit, which can satisfy any three targets measurement simultaneously. And the pyrometer also has the advantages of small size, portable, high stability.