Question 9.CSGP.168: A jet-ejector pump, shown schematically in Fig. P9.168, is a......
A jet-ejector pump, shown schematically in Fig. P9.168, is a device in which a low-pressure (secondary) fluid is compressed by entrainment in a high-velocity (primary) fluid stream. The compression results from the deceleration in a diffuser. For purposes of analysis this can be considered as equivalent to the turbine-compressor unit shown in Fig. P9.157 with the states 1, 3, and 5 corresponding to those in Fig. P9.168. Consider a steam jet-pump with state 1 as saturated vapor at 35 kPa; state 3 is 300 kPa, 150°C; and the discharge pressure, P_5, is 100 kPa.
a. Calculate the ideal mass flow ratio, \dot{ m }_1 / \dot{ m }_3.
b. The efficiency of a jet pump is defined as \eta=\left(\dot{ m }_1 / \dot{ m }_3\right)_{\text {actual }} /\left(\dot{ m }_1 / \dot{ m }_3\right)_{\text {ideal }}
for the same inlet conditions and discharge pressure. Determine the discharge temperature of the jet pump if its efficiency is 10%.
a) ideal processes (isen. comp. & exp.)
b) real processes with jet pump eff. = 0.10
State 5: h _5=2749.3 \,kJ / kg , P _5=100 \,kPa \Rightarrow T _5= 1 3 6 . 5 { }^{\circ} C