Method for on-site calibration of a thermal flow measuring device, method for carrying out a temperature-compensated flow measurement and thermal flow meter

摘要

A method for on-site calibration of a thermal flow meter in a measuring medium, wherein the thermal flow meter at least a first sensor element, which is designed as a heater, and at least a second sensor element, which is designed as a temperature sensor, characterized by the following steps: I Entering at least two different flow rates and / or flow rates for at least two measured different power coefficients for the measuring medium, II. Determining Reynolds numbers for the respective data pairs from a power coefficient and a flow rate and / or flow rate associated therewith; III. Determination of temperature-compensated Reynolds numbers from the at least two different power coefficients using mathematical models to describe an internal and an external heat transfer of the flowmeter in the medium under consideration of the thermal material properties of the medium; and IV. Creation of a calibration curve by assigning the determined Reynolds numbers from step II to the determined temperature-compensated Reynolds numbers from step III for a respective power coefficient, and a method for performing a temperature-compensated flow measurement and a thermal flow meter.