- #1
JSBeckton
- 228
- 0
Consider a water pump that receives liquid water at 15C and 100kPa, and delevers it to a same diameter short pipe having a nozzle with exit diameter of .01m to the atmosphere at 100 kPa. Neglect KE in pipes and assume constant internal energy u for water. Find exit velocity and mass flow rate if the pump draws 1kW of power.
I started with the energy equation but since the pressure and internal energy is the same, won't the he and hi also be the same? If I reduce I get
[tex]
\begin{array}{l}
\omega = - \frac{1}{2}V^2 \\
V = \sqrt { - 2\omega } \\
V = \sqrt {( - 2)( - 1kW)} \\
\end{array}
[/tex]
Which isn't giving me the right velocity of 29.43 m/s. I know it has to do with the exit area but its not comming to me, can anyone point me in the right direction? Thanks.
I started with the energy equation but since the pressure and internal energy is the same, won't the he and hi also be the same? If I reduce I get
[tex]
\begin{array}{l}
\omega = - \frac{1}{2}V^2 \\
V = \sqrt { - 2\omega } \\
V = \sqrt {( - 2)( - 1kW)} \\
\end{array}
[/tex]
Which isn't giving me the right velocity of 29.43 m/s. I know it has to do with the exit area but its not comming to me, can anyone point me in the right direction? Thanks.