 #1
 1,380
 22
Homework Statement
A pump is on a line. the data are:
P_{1}=0.4[bar]
[itex]\gamma[/itex]=0.8[itex]\cdot[/itex]10^{4}[N/m^{3}]
V_{1}=3[m/s]
[tex]\frac{D_1}{D_2}=1.4[/tex]
H_{P}=30[m] (head of pump)
See attached drawing.
Homework Equations
Bernoulli equation:
[tex]H_1+\frac{V_1^2}{2g}+\frac{P_1}{\gamma}+H_P=H_2+ \frac{V_2^2}{2g} +\frac{P_2}{\gamma}[/tex]
The Attempt at a Solution
The velocity after the pump:
[tex]V_2=V_1\frac{D_1^2}{D_2^2}=3\cdot 1.4^2=5.9[/tex]
Bernoulli equation:
[tex]\frac{0.4\times10^5}{8000}+\frac{3^2}{20}+30=0.3+\frac{5.9^2}{20}+\frac{P_2}{\gamma}[/tex]
[tex]\Rightarrow\frac{P_2}{\gamma}=27.9 \Rightarrow P_2=2.2\times10^5[/tex]
The answer should be 1.87x10^{5}[pa]
Attachments

1.9 KB Views: 367