Thermodynamics - Final Exam with Answer Key | ENSC 2213, Exams of Thermodynamics

Download Thermodynamics - Final Exam with Answer Key | ENSC 2213 and more Exams Thermodynamics in PDF only on Docsity! ENSC 2213 Thermodynamics } sey FINAL EXAM / 12-05-16 (5) Problem 1. It is your first day on the job wit! 4, a dry ice manufacturing plant, and your superviser already needs you to uo an eme ey Calculation. In the dry ice manufacturing plant 8 Ibmol of gaseous carbon dioxide at Ti = 493°R and p: = 320 Ibffin? is compressed at constant pressure in a piston cylinder device. The work required for the compression process is —2000 Btu. The final volume (V2) of the gas after the compression is a key variable for the next processing step. Determine the final volume, V2 (in ft’). Do NOT assume ideal gas behavior for the gaseous carbon dioxide. We frdver(K-y) smu RR ~ Ib = we _ -2000 BI. (77% FRE) 2. ae Pe (3z6 Noe 2\( pay in gy) Find Uf Using Cormpprest bi hy Chart pa gn eZ) oe Teal 1 RT 27; nRT BV. nS oy Ae Where Tp plang SAGES Oa = god eee. a ) TB S4F'R nef © 9.244 0.3 Pr 320 yy. en iA eS 0.4 atm) tT A atm) : ; x ¢ Fes a ee a v4. A 1 with TR, = 0-4 ‘ 2 oo" ove BaD (% omal Name) i 5) WEY my inet \szo BENG _ 0.85 va nRy, =, _ * S, eet f 3 3 f.2_ 33.77 Ft ame = 9) \i2-ot0 Y, ~ Vi8-) M2 sc 1%. 63 i — ty ENSC 2213 Thermodynamics Nam CXAM Key FINAL EXAM / 12-05-16 ae (25) Problem 2. A well-insulated steam turbine operates at steady state. Steam enters the turbine at pi = 1600 lbffin? and T; = 1000°F. Twenty five percent (25%) of the steam entering is extracted midway through the expansion process in the turbine at p2 = 160 Ibf/in* and T2 = 450°F. The rest of the steam exits as saturated vapor at p3 = 1 Ibffin’, The turbine develops a power output of 9x10® Btu/hr. Assuming negligible kinetic and potential energy effects, determine the mass flow rate of the steam entering the turbine (7m,), in Ibm/hr. sTear From (gus, YF PIASS Re teoo MFfin™ © , ‘ ‘ 0 221, = gl omy, Fa T = 1000 °F We 4x10 8 a m, = z |_—_——> fe he 2 r= tA, = 0.25, Ree Ont as 2 < 6.25), sah Vapor : : : « TEAS Be ee): dng - 1, - 25m, Seg wh ie pa tl Be. = S0PF For steady stah, ptrabatiy proces wrk, Axe g APE td), reryy % (et law) reduces & ire ape Beeps Wi, Phy 1.28%) he — -% 25m, )hs W. , (h, - 625h2- hy + 42543) PN eis eo 25h, — 2 "3 Bh. £, - 1246.1 wher Yrom Tabk A-¢& > fy, stt87+! 2 = ree Rhu /lom Sega /2 A-tG: eg = 05.8 Bu % Bh/h a= tate z ao ie (0.15)(105-2)] Btu/lbm Ass: Mo a ka: Neen rn 4, Ai h-S3 624. & o ~ x19 Bli/hr Po, = 4,514,961 bye eb Mi = ENSC 2213 Thermodynamics NA oe a ae  a NaMe_EXAM Key ENSC 2213 Thermodynamics FINAL EXAM / 12-05-16 (40) Problem 5. Consider an ideal ait-standard (variable specific heat analysis) Diesel cycle. € pl ‘essure and temperature at the beginning of the compression process are 94,9 kPa and 300 K, respectively. At the end of he at addition process, the pressure is 7.2 MPa and the temperature is 2150 K. For this cycle determine: p (a) The temperature at the beginning of the heat addition process (in K), 2 3 (b) The compression ratio, 4 (c) The cutoff ratio. (d) The temperature at the beginning of the heat rejection process (in K), ‘ (e) The pressure at the beginning of the heat rejection process (in MPa). Givin; T= 300K , Fe 44 KP Tg: sok, R= 7.2MPa = LA) For an Isenfropic process lene) 7200 mes 05.2 P. —oseniaes = Mee AS a2 Bh \ AY. 1 Pa Ly From able A-22 an = 360K Fron Table A-22 wilh Rs los2 a> [T= 480K ce From Tabi At @ Ty = Beg &’) re Vr, ie 2), & aes aves a2 aia, T -480K \ From Tab A-z2r @ Te = Coe eens Ta ONES Ae eo ry _ 222 (2.175) = 22.4 ey (d) Veg e % “ry ae. 2 ( bes from Table A~2% é = Ts ao soX ane blaction ae ee ee = t2.7 <> | 4 From Wake A-2L © 14 40 30 2b MPa & 24.35 12 MP, es [ose MPs | () We aN r= Benes u ( ¢) 3 ZS 3A Feem Tb A-22 @ Taz 2is0 Kk SS > EXAM K6EY EENSC 2213 Thermodynamics NAME FINAL EXAM / 12-05-16 (30) Problem. 6. gerant i vapor-compression i ing fluid in an ideal vapor-co! 3 Refri it 134a is the working wld. in refrigeration cycle operating under the following conditions: Q TS ig ee bist ht Meena dt camne att) if MAPe 1 ENSC 2213 Thermodynamics name. EXAM KE FINAL EXAM / 12-05-16 (30) Problem 6, Refrigerant 134a is the working fluid in an ideal vapor-compression refrigeration cycle operating under the following conditions: Compressor inlet condition: Saturated vapor at 0.16 MPa Condenser exit condition: Saturated liquid at 0.70 MPa Refrigeration capacity: 3.5 tons For this cycle determine: (a) The mass flow rate of refrigerant (in kg/s). (b) The power necessary to drive the compressor (in kW). (c) The heat rejected by the condenser (in kW). (d) The coefficient of performance. \A) From & (0.3) = Qin a where from Table AN @ R= Ole MPA = 4G bar 6 Sak Mpéor be Wig 2341 KS/ey 2 Si Sg = 0424S MT eg Poem TC Asap @ RB = Pe = 9.7 Pa e (oary emer. lignid hs: h3g = SUVS ‘Sieg For thro MHlry gorg less Reta te Stns he Sd hes Be ep (3.5 fms) 21) 1S min SS = 10,084 Ka. (237. 47 SU.18) KT ic, (6) ™% = hy A,) peenteeg, | Tadic Ante ©. “le = fIMP. =7 bar g S2-S,= 0.4295 25 hag = 268.40 KT/e, (eh trterpalarvon) HZ = 0.0814 KS (205.40 ~ 237.97) 82 =| 2489 KW | 2 a0 £s ( yx. [Baw iS Qout ™ Cha hs) Qo = 0.0F4 a (26% 40~€6.78) x ~ [4.4% Kw a ee _ Ba - %o13) ‘i == his A, (26 ¢.40 ~ 237.97) KF), =[4.97 = 5] W M, Ae