Calibration method of thin film thermal resistance heat flow meter and coaxial thermocouple for heat flow test

Abstract

The invention discloses a calibration method of a thin film thermal resistance heat flow meter and a coaxial thermocouple for a heat flow test. The method comprises the steps: determining a calibration heat flow range, and selecting a calibration heat flow value; spraying a coating on the surface of the heat flow sensor; acquiring the output of the heat flow sensor under a certain calibration heat flow; moving the heat flow sensor out of a calibration position, fixing a water-cooling Gardon meter, and acquiring the output of the water-cooling Gardon meter; acquiring the outputs of the heat flow sensor to be calibrated and the water-cooling Gardon meter under a series of calibration heat flows; processing the heat flow sensor output to obtain an output average value; calculating the input heat flow of the heat flow sensor by using the nominal sensitivity coefficient of the water-cooling Gardon meter and the output under a certain calibration heat flow and combining the absorptivity of the surface coating of the heat flow sensor; and fitting the average values output by the multiple pairs of heat flow sensors and the input heat flow by using a least square method to obtain the sensitivity coefficient of the heat flow sensors. According to the method, the requirement of a heat flow sensor test value for definite value traceability is met, and a reliable uncertainty evaluation result is provided.

Description

technical field [0001] The invention belongs to the technical field of heat flow sensor calibration, and more specifically relates to a method for calibrating a thin-film thermal resistance heat flow meter and a coaxial thermocouple used for heat flow testing. Background technique [0002] At present, in pulsed wind tunnels such as shock wave wind tunnels, heat flow tests are mainly carried out by using thin film thermal resistors and coaxial thermocouples. When using thin film thermal resistance or coaxial thermocouple to carry out heat flow test, the surface temperature obtained by these two sensors is used to obtain the heat flow test result by inversion. The difference is that the thin film thermal resistance uses the linear dependence between the resistance and temperature of the platinum metal thin film to achieve temperature testing, while the coaxial thermocouple uses the Seebeck effect of different thermocouple materials to obtain the surface temperature test result...

AI Technical Summary

Problems solved by technology

Obviously, the product of pyroelectric coefficient and thermophysical parameter determined by this two-step method will inevitably introduce more error factors when evaluating the uncertainty of heat flow test results

At the same time, some literature pointed out that the heat flow results estimated by the Cook-Feldeman method are not accurate enough, and the Cook-Feldeman method is often used when estimating the effective thermophysical parameter product

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