Use the data given in Problem 12.18 and plot the dimensionless coefficients (C_{H}, C_{mathscr{P}}, eta) versus (C_{Q})

Question:

Use the data given in Problem 12.18 and plot the dimensionless coefficients \(C_{H}, C_{\mathscr{P}}, \eta\) versus \(C_{Q}\) for this pump. Calculate a meaningful value of specific speed, discuss its usefulness, and compare the result with data of Fig. 12.18.

Fig. 12.18

Problem 12.18

The centrifugal pump shown in Fig. P12.18 is not selfpriming. That is, if the water is drained from the pump and pipe as shown in Fig. P12.18(a), the pump will not draw the water into the pump and start pumping when the pump is turned on. However, if the pump is primed [i.e., filled with water as in Fig. P12.18(b)], the pump does start pumping water when turned on. Explain this behavior.

Figure P12.18