S11_test2

# S11_test2 - MAEZSI Test 2 Spring 2011 Closed book — time:...

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Unformatted text preview: MAEZSI Test 2 Spring 2011 Closed book — time: 55 min — grading: 10+10 1. Air (ideal gas, cp = 1 kJ/kg.K and R = .287 kJ/kg.K) enters a 2-stage compressor with intercooling. At the entrance of the lower stage (point 1), the air is at 20°C and 100 kPa. Both stages have an isentropic efﬁciency of 80%. At the exit from the ﬁrst stage (point 2), the air at 300 kPa is cooled back to 20°C at point 3. The second stage brings the air to 1000 kPa at point 4. Show and label the processes on a T—s diagram. Per unit mass ﬂow rate, calculate the heat exchange, the compression power, and the entropy production rate in the compressor. 2. An ideal steam turbine is equipped \ with a bypass valve, as shown on the diagram. The incoming steam is at “W pressure p1 and temperature T]; the l mixing of 2 and 3 is at constant / pressure p4, and T4 is also given; /T- neglect kinetic and potential \\ energies, and stray heat transfers. Select the best thermodynamic diagram for this situation (explain 5 \ ML 1 brieﬂy) and label it to show the various processes. For a unit mass ﬂow rate at point I, calculate the V Lf turbine power and the mass ﬂow rate through the valve. Conversion factors: 1 bar = 100 kPa 1 Btu = 778 lbfft 1 psi = 1 lbf/inz gc = 32.2 lbmft/lbfsz K=°C+273 OR =°F+460 £9 4 300tpa —“9 “'"5 L000 bPa ——§ 1:71 \$qsrs J C} m m K: J. _— w 5 5% [‘25 O : “Rafa-€25 has? (SJ 05% taxi-715) 14:} :: 267 " 4’ E, K ‘ C230 Calm :: ’(096 keg/(<3? (CchngK EMA Wu 2435.4? (fl/13>. (2,3,- 0 : app JFQTAﬂ? —— I : avg-(2:5) :~t3:8 Lﬂ/zﬂ (:ugrf‘} 3>:%S W ES .: EFH (C fwm :; —L2_1(<3/5o 7 wax wﬁv— LSLzlc'aﬂ L Toke/Q wwkﬁgi: wt;ij : 237 LUKE kf Evd’T‘O Can/aouuoz [~22 _Q: O :b S ‘31 +611 T2. 1. M .3}2 : bﬁiﬁgﬁ 8%th s: : 57% .3 ~ “ @7213? :28 0' T\ 7; 7a 20%“: . H 4% L’G/(cg L ...
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## This note was uploaded on 04/02/2012 for the course ECS 222 taught by Professor Staff during the Fall '08 term at Syracuse.

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S11_test2 - MAEZSI Test 2 Spring 2011 Closed book — time:...

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