| 摘要 |
The invention relates to a device for determining a mass-flow of a fluid (20), comprising a line (10) for conducting said fluid (20) in a flow direction to a contact with a heat exchanger (30), a first temperature measurement point (51) being arranged upstream of said heat exchanger (30) in order to determine a first fluid temperature, a second temperature measurement point (52) being arranged downstream of the heat exchanger (30) in order to determine a second fluid temperature, and said heat exchanger (30) having a surface temperature (33) that is constant in the flow direction and can be recorded by a third temperature measurement point (53). The invention also relates to a method for determining a mass-flow of a fluid (20), in which a series of measurements are taken at the first temperature measurement point (51), at a constant mass-flow and constant fluid temperature, with a modified heat output (40) being applied to the fluid each time. The data sets are expanded with parameters for the respective systematic errors, and are transferred to two analytical functions A and B which are based solely on the same variables. The A and B functions formed in this manner are then merged together to obtain a common quantity of data. Finally, the systematic errors are determined as free fit-parameters of a fit-function in which the scattering of the data quantity is minimised. The mass-flow is supplied by the fit-function, and its exactitude depends on statistical uncertainties only. |
