FIGURE 13-8
-A paint sprayer pumps air through a constriction in a 2.50-cm diameter pipe, as shown in Fig. 13-8. The flow causes the pressure in the constricted area to drop and paint rises up the feed tube and enters the air stream. The air stream in the 2.50-cm diameter sections is 5.00 m/s. The density of the air is 1/29 kg/m³, and the density of the paint is 1200 kg/m³. What is the maximum diameter of the constriction that will allow the sprayer to operate?

Question

FIGURE 13-8

-A paint sprayer pumps air through a constriction in a 2.50-cm diameter pipe, as shown in Fig. 13-8. The flow causes the pressure in the constricted area to drop and paint rises up the feed tube and enters the air stream. The air stream in the 2.50-cm diameter sections is 5.00 m/s. The density of the air is 1/29 kg/m³, and the density of the paint is 1200 kg/m³. What is the maximum diameter of the constriction that will allow the sprayer to operate?

Quizplus · Accepted Answer

The maximum diameter of the constriction can be found using Bernoulli's equation and the continuity equation. The pressure drop must be sufficient to lift the paint, which depends on the velocity change and the density difference. Solving these equations gives the maximum diameter as 8.09 mm.

FIGURE 13-8 -A Paint Sprayer Pumps Air Through a Constriction in a Constriction