摘要 |
The real mass flow rate is calculated for a variety of gases. The variety of gases are classified into a plurality of classifications, and representative discharge coefficients are previously determined for the respective classifications. When an upstream pressure and a temperature are detected for a certain gas on an upstream side of the sonic nozzle, a theoretical mass flow rate is calculated. After the theoretical mass flow rate is calculated, reference is made to a theoretical mass flow rate-discharge coefficient correspondence table recorded in a memory corresponding to the classification of the gas to select a desired discharge coefficient. After the discharge coefficient is selected, a real mass flow rate is determined with a product of the selected discharge coefficient and the theoretical mass flow rate.
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