Unformatted text preview: pered tube
to an equilibrium position which is
a measure of the fluid-flow rate.
(Courtesy of Blue White Industries,
Westminster, CA.) Cd Aa 1/2 2Wnet
Afloat (6.121) fluid where Wnet is the float’s net weight in the fluid, Aa Atube Afloat is the annular area
between the float and the tube, and Cd is a dimensionless discharge coefficient of order unity, for the annular constricted flow. For slightly tapered tubes, Aa varies nearly
linearly with the float position, and the tube may be calibrated and marked with a flowrate scale, as in Fig. 6.35. The rotameter thus provides a readily visible measure of the
flow rate. Capacity may be changed by using different-sized floats. Obviously the tube
must be vertical, and the device does not give accurate readings for fluids containing
high concentrations of bubbles or particles. Coriolis mass flowmeter. Most commercial meters measure volume flow, with mass
flow then computed by multiplying by the nominal fluid density. An attractive modern
alternative is a mass flowmeter which operates on the principle of the Coriolis...
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- Spring '08
- Fluid Dynamics, e-Text Main Menu, Osborne Reynolds