MEN 310 Final with Solution, Fall 2000

ph (assume engine oil) at 20°C enters a pipeline made of stainless steel and flows atanaverage “?/ : 1 Notre Dame Universicy Faculty of Engineering Mechanical Engincecing Dep, 1. foo PINAL MEN310 (Heat Transfer)’ February 02, 2001 Hot air at 2 atm and 127°C witha mass flow-rate of ] kgs flows across a finned tube bank of configuration shown in fig.P] and exits at 27°C. Water at 15°C and a mass flow-rate of 4 ko/s _ flows inside the tubes. The overall: dimensions and geometrical characteristics of the heat exchanger are as shown in the figure, The material used for both tubes and fins is copper. Determine: _ : _ ries } ts . ot : Cae SyR rie Beemer cae lee - 20a : - a) the total heat transfer rate and the outlet temperatures of water, . . a: \\ - has.a.30-cm inner diameter and 32-cm outer diameter. Determine the temperature of the oll - £2 b) the overall heat fransfer coefficient as well as the heat transfer.coefficients air and water aye ‘Sides. bea AK 3 SE, verie : a velocity. of 1 m/s. The pipeline is 200-m-long and is submerged in a lake of icy water at O°C. Ie when the pipe leaves the lake and the heat lost to the icy waters. fa (3a vertical exhaust pipe (12-cm ID and 12.2-cm OD) carrying combustion gases at 900°C (16% CO2, 8% HzO and 76%N;) and located in a large conditioned space maintained at 22°C is to be insulated for radiation. To do so, the pipe is inserted into a cylindrical radiation shield (24-cm ID and 24.4-cm OD) of unknown surface condition, The pipe is made of tumed cast iron and assumed to have negligible resistance to heat transfer by conduction. The sucrounding walls are made of rough red bricks with no gross irredilarities and are assumed to bé at 25°C. Determine the emissivity of the shield in order to reduce the radiation heat transfer between the exhaust pipe and the surrounding walls to one tenth of that without the shield. Find the net radiative heat transfer rate per unit length of pipe and calculate-the equilibriuti temperature of wee the shield. Neglect conduction and free convection-effects. ‘ : 7 aN \ ab Points: (60%) 2 (30%), and 3 (20%) RATS den Ef . fi = Mee Water a4 Ax 9th ju 7 7 ar » 6 > tal! 3 ” ton 4 ‘a _ {vie ye sy ip ‘ LK oe oad a - G 1 - Fig.P! Cross flow heat exchanger. as HA Hot erm Pa ddim . waka te IS°C 5 Te 1a+°c. We UK lsoe : = Male | t ate. a) 9 -Q=mcAl (Per ode) | °° _ {x to0e x too= 1Q0600 Wells < 14 —» 1006002 Ux tiBox (at) —> AT= © .ol6 * AT... 4 3-143 — Vos, = QL. 016 THOS. mo b) Us? me} on - { % looG ~ \00G —> Cin — 2. Ux4iBo 216420 Cy : —, €- Mor _ 0.8927 « Onin C= 0.06 BV nay, Cate . L AC=aNTV = AY — . AV= QGIS.6. Usg FR. lo-l —x P20.052 , Rz-1 6.62 Conder , b= wae TEL.: 950415 - TELEX: 20049 AQUALI LE - B.2 80106 -BEYROUTH - LIBAN wr - mM oi « Pu > Por & b= Sldlpet{s” 2 a tee BC _ Be Ne TRE FY = mo _ Ube, 0 Bulor~ 7 e Pa ~ . _ 469.2 Ct, OsFxto 1) gp (e120) «(23 i) KR, . 6o0fF20.O0F. ee hwa ~ Hastbiethcliaiian.; Co. $98 £2 fre 7.24G. eo ¢ we ot | ‘dy saes A\cerreng Qu T. rd) L Ve 5. aolaNy wfgec. ;j . Pee 19990 ; P2890.987S Re. 1xo-B 2 MH. SIT <2300 wd Remieson- 2 #mes P. * {\4o4SS- 7 - ~ wus Tek Lop. (O1) = % pO. a ” 4 p oy | Ly ee 6 . i ? Nu, > 30 OGMHAN S | he WSBIL hoe} Ip. =!8C 5 TL) = aeele ust. 3 ou meet cystine? ph 0145S bes. . Theay ak 4 Tes _ulo Anwpossctle + Ce atth La: Tea TE), Tee 23.185 Lonpesetete ha, TEL: 50415 - TELEX: 20049 AQUALI LE - 8.780106 -BEYROUTH- UBAN Zool 7 eae; on en g* Cc x2 20 = Po fi. 2 Fable. — Praz ju. Lae. 3 - qe ane At « ¥ Io C8284 atts. L. co TWaeg TE = Te. Tees 940. Is. “Cit: RA oe Sev : ge ek Fs seach. «ae to “s 5 TR {T= 1S.67°C| © Cue to oon comacnlice & “Tags. 0°C Tes = IS.6F°C. Tent S.GF . 4,835 6 °C. — 280.838 ~ 281K Ly Yu ho oS Pre ee weésy gf Pcp 2 4.616 th x10”, ae . Lb Grice 23t0SF4340F = Q3tR 107 ven Y oe - Neg = C(Gete)” 2 ond (Gr?) 7% 2 1495338 —_ fo 3i4 tly Wiree Sic hey > arnt Ea + Aci «ten® ai hA > SR aioe egies Teh lps qu mcAT = “Dene at, <9. Lepp > €R. 3. Wesco. eis a Sus os gree tov © os uty ba Tee mpeg @ a pS cee eee << Taking TWsSC mashidling fos ei 3 cabculete- Se aaaaied Veet 3: Jau-23,2c0! 32 pak = (sxe Solved protien ere ( This soltion ns mol Ake, & The Qarrnnfilion § Guay tee mA ad Be. 2 x te valles shawl wet’ oe LLL. i €-?2 © Vert? Wnat: unik medkidd: ¢ AS RA qe CC -T) . A, (i- €A,o -T") \-21 ~ { Loa ZA, FLA, qy. ee 2 ; _ Ge, x, J.=Eb, wo one ae - a; we Sid. ; a ve vn Te t-% 1-%, \-8, & aw ZR, A, m %,A, aA, sub9 g- @ a(t -t) - TS) 4 . “tet LL let tk, R BA, AF, ZA, ZA, . 5 e att q:itq . -» SB coPecy_ i. £0, EE Aw ol} \ no shi 7 49 S & \=_$3 . \ \- 3 ml = , ods BA Re Io 1-4 sa” freer) EG R \S =A, (Teo 122) . ve . \ = FS 4 = —> Ta's 4, ‘4 3 . \