The most likely selections for this application are Coriolis mass flowmeters (Answer A) and positive-displacement flowmeters (Answer D). Coriolis mass flowmeters have good accuracy and have the advantage of measuring mass flow directly without having to compensate for density. Positive-displacement flowmeters also measure accurately but do not inherently compensate for density, so independent temperature compensation may be advisable in some applications. In general, there appears to be a trend away from positive-displacement flowmeters (traditionally used in this service) toward the application of Coriolis mass flowmeters.
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The other technologies could be applied in some applications. For example, some differential-pressure flowmeter geometries (Answer B) could be applicable if Reynolds number constraints are satisfied. When the liquid is conductive, magnetic flowmeters (Answer C) might be applicable. Vortex shedding flowmeters (Answer E) can sometimes be used in applications where the liquid is viscous at ambient temperature, but less viscous at (higher) operating temperatures.
Additional Complicating Factors
The actual fluid composition and temperature can affect the density of the liquid, viscosity of the liquid, and Reynolds number at flowing conditions. Coriolis mass flow measurement systems tend to inherently compensate for many of these variations whereas positive-displacement flow measurement systems may do so to a lesser extent.
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