Exam 3 with Answers | Thermodynamics | ENSC 2213, Exams of Thermodynamics

Download Exam 3 with Answers | Thermodynamics | ENSC 2213 and more Exams Thermodynamics in PDF only on Docsity! ENSC 2213 Thermodynamics EXAM 3 / 11-19-10 NAME _ (25) Problem 1. Two Carnot engines operate in series. The first cycle receives energy by heat transfer (QH,I= 500 kJ) from a high temperature reservoir at TH= 727°C and rejects energy (Qe,l) to a reservoir at an intermediate temperature TI = 427°C. The heat rejected from the first cycle (Qe.l) is the heat input to the second cycle (QH,2).The second cycle produces half the work of the first cycle and rejects heat (Qe,2) by heat transfer to a cold temperature reservoir at Te. For these cycles determine: i _ 11 _ (a) 111, (b) WI (kJ), (c) QH,2(kJ), (d) 112,and (e) Te (OC). ~r...,t-. l""! - ~ td QH\ ~ Soo xr Qc..l : ~I-\ 1.. 11-\ ,,-,L/'C Tc.. :. ~nol Yl. ~I - .vJ). , ------ '0) .~~I-~ ==) QLI~~5DKy ~OD --- ()(.t-W~Cl.~ W,-=-QH -~ :: ~ -3So \ \rJ I -=- ISo ¥:-Y"j C) ~\iL -=- t{CI ~\~~O~ :"QH\. J\ '11.~ I -h~\-~c.. -::..... It. - L _y, - 0.e..-1- 'Ii Q.~ I TI-\ - 0:----:-- 'wo\\. - ~5()1<f Yz..W, -.::Wl. := IS KT = QI-t - ~c. '») ~~~D-Qe-. Oc.. :. J,.iS"l\J -=~ l.. 'I- <..~-1)00 ILl. :.5S-o ( lie..- :: 177 'c, I Problem 2. Carbon dioxide @n ideal ~ with variable specific hea~s) contained in a piston-cylinder assembly undergoes an expansIOn process from TI = 400°F, VI = 15 ft3/lb to T2 = 200°F, V2 = 25 ft3/lb. ENSC 2213 Thermodynamics EXAM 3/11-19-10 NAME _ (a) Determine the change in the specific entropy of the carbon dioxide (C02) gas between states I and 2 (Btu/lbmol.oR) using data from ideal gas properties table (Table A-23E). (b) Can this expansion process occur adiabatically? (Justify your answer quantitatively.) ~" :: \t.\ ~I":-l~~~~l~ D.R,) \~ S't - <;, -= S1.~~tj- bt;, -= -,. l\' ? ~ l~)[~ff~\ 'l.~