For a long time, because of the lack of unified standard, large range of heat flux sensor calibration is a common issue. The main difficulties include the establishment of high temperature heat source and the determination of traceability system. Currently, more common heat flux sensor calibration method is blackbody radiation law, which establish the relationship between temperature of blackbody and radiation heat flux, so as to realize the calibration of heat flux sensor. In practical applications, large heat flux means a very high temperature of blackbody because of the positive relation between radiant heat flux and temperature. However, long times work of blackbody furnace especially at a high temperature can lead up to giant energy consumption and great security risks. Based on this consideration, some scholars proposed the establishment of a laser calibration system which use the laser as heat source, which combines the advantage of single wavelength, energy concentration, safe and controllable. Through establishing the relationship between radiation heat flux and optical energy, can also trace radiation heat flux to the optical energy. CO_2 laser work in single wavelength, is an ideal high energy heat source. In this paper, a calibration system based on CO_2 laser is designed on the principle that heat flux can be traced to optical standards. In the system, a carbon dioxide laser, optical lens array, a turntable, data acquisition system, an optical power meter, a heat flux sensor are included. The optical lens array convert the laser into a kind of parallel light whose energy density obey a flat topped Gauss waveform. Then the optical power meter and a heat flux sensor be positioned on the turntable which controlled by computer, in order to keep the sensors can be switch to the same location when works. As the effective aperture is known, the energy density can be calculated when optical power meter works. So that, the sensitivity of the sensor can also be known by the output and the calculated energy density. Through experimental tests, the test data of the laser calibration system is credible. The heat flux energy density from the laser calibration system reach as high as xxMW/m~2, and the peak value fluctuation above xx%.
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