When applied to measure air velocity, a Pitot tube records a water manometer deflection of 5 cm, corresponding to an air velocity in m/sec of___________________?
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Answer: D. 28.2
Explanation
A Pitot tube measures the velocity of a flowing fluid by converting kinetic energy into a stagnation pressure head. Applying the standard velocity formula for a water manometer deflection of five centimeters with air yields approximately twenty-eight point two meters per second. Accounting for the density difference between water and air is essential in calculating the correct fluid velocity. The Pitot tube equation relates fluid velocity to the square root of two times gravitational acceleration multiplied by head. Manometer liquid density must be converted into an equivalent column height of the flowing fluid being measured. Air has a much lower density than water, resulting in higher flow velocities for a given pressure head deflection.
A velocity of five meters per second underestimates the flow rate by neglecting proper density conversion factors. A velocity of fourteen point one meters per second represents a calculation error involving square root scaling. A velocity of fifty-six point two meters per second overestimates the air speed corresponding to a five centimeter water head.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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