Uncertainty control method for flow calibration by using high-temperature ultrasonic flowmeter

The invention discloses an uncertainty control method for flow calibration by using a high-temperature ultrasonic flowmeter, which comprises the following steps: firstly, calibrating the qualified high-temperature ultrasonic flowmeter by using an ASME flow nozzle which is verified to be qualified, and the calibration process is required to be carried out in the same pipeline environment as a calibrated working medium; secondly, selecting an optimal ultrasonic flowmeter to calibrate a measuring point; secondly, accurately measuring pipeline parameters, such as pipeline diameter and wall thickness, which have important influence on flow calculation; thirdly, a dual-track measurement technology is adopted for the same measurement point; and finally, the measurement environment condition of the working medium in the calibration and calibration process is controlled, and high-precision calibration of the flow device which is inconvenient to disassemble in the power station is achieved. By means of the method, the