| Popis: |
In the present investigation, a new design flow meter with pressure detection has been optimized and investigated numerically. In the classical design of the KROHNE flow meter a paddle is used as a sensor, containing piezoelectric elements. When flow passes around a bluff body periodic flow separation develops which is responsible for the oscillation of the paddle. Thus the piezoelectric elements transform the mechanical movement of the paddle in electrical signal which can be evaluated in signal processing. Such a sensor construction is restricted to medium temperatures until 240°C. In order to achieve an accurate measurement at higher temperatures, for example at 500°C, a new design flow meter has been developed. Instead of using a paddle which is positioned to detect periodic flow fluctuations, the periodic change of pressure is detected through two openings which are positioned at the side wall close to the bluff body and leading to a pressure chamber. The periodically changing pressure acts on a membrane and thus with a suitable sensor design it is possible to detect the underlying frequency. |
