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Large | v v As so often happens, the product of inefficiency and initial cost is approximately constant. | e-Text Main Menu | Textbook Table of Contents | Study Guide 402 Chapter 6 Viscous Flow in Ducts 1.00 0.98 Cd 0.96
0.316 < β < 0.775
1.5 × 10 5 < ReD < 2.0 × 106 0.94 0.92
0.3 Fig. 6.42 Discharge coefficient for
a venturi nozzle. 0.4 0.5 0.6 0.7 0.8 β The average nonrecoverable head losses for the three types of meters, expressed as
a fraction of the throat velocity head V 2/(2g), are shown in Fig. 6.43. The orifice has
the greatest loss and the venturi the least, as discussed. The orifice and nozzle simulate partially closed valves as in Fig. 6.18b, while the venturi is a very minor loss.
When the loss is given as a fraction of the measured pressure drop, the orifice and nozzle have nearly equal losses, as Example 6.21 will illustrate.
3.0 2.5 Thin-plate
orifice hm 1.5 Km = Vt2/(2g) 2.0 1.0 Flow
Venturi: 0.5 | v v Fig. 6.43 Nonrecoverable head loss
in Bernoulli obstruction meters.
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This note was uploaded on 10/27/2009 for the course MAE 101a taught by Professor Sakar during the Spring '08 term at UCSD.
- Spring '08