MEN 310 Exam 3, Fall 2000

°F Bote Dame University Faculty of Engineering Mechanical Engineering Dzp. TEST— MEN310 (Heat Transfer) January 23, 2001 O) radiation shield is placed between two parallel plates. The radiation properties and the surface conditions for each plate are as s follow: , : 4 Plate I: T\=1000K, £;=0.8 °. Plate 2: T2==500K, €2=0.5 Determine the emissivity of the shield in order to reduce the radiation heat transfer _2 between the plates to one tenth of that without the shield. Find the net radiative heat transfer rate per unit aréa between plates 1 and 2 and calculate the equiltbrium temperature of the shield. ooo . 2. Consider the flow of oil (assume engine oil) at 20°C inlet temperature in a 30-cm- diameter pipeline at an average velocity of 2 m/s. A 200-m-long section of the pipeline passes through icy waters of a lake at 0°C. The pipe walli is characterized by a negligible resistance to heat transfer. 8 a) Assuming the pipé wall temperature equal to 0°C, determine the temperature, of the he Tos = oil when the pipe leaves the lake and the heat lost to the icy waters. . eke 7 b) Instead of the O°C wall temperature assumption, one can «argue that a 20°C wall mah [oe temperature is a better assumption. Determine the heat lost’ by the pipeline during its +} passage in the lake. 16) In your opinion, which assumption (a or b)i is better to correctly represent the real a heat transfer behaviorof the pipeline in the icy waters. Explain. ~ Points: 1 (40%) and 2 (60% or 25%t25%+10%). senasy y T= look ; €= 0% | Te Sook j Eve 05 @ | E-? 4 = Li idl ) acai, $33 Rup _ t 23620 Yar aing + > Reta \ ta FT iggy: 2862-BABOLL | ay EL. ~ Eb. won 2 e-an Ss = = rG, -T) Maing =Pgune —? A etek Pao =e —_ SR. eG + { + 2 2) + = ® =f = OU |, @ .oS}| a) aks radiitive Rast Sanpete randy elles Q = 2362. 0883 W/n. . F > = — _€ he , to Die 8-32 7 gq. Eb Eb, —s Ess - Q vk Z e-%s _ ry (settee wt ee . 29954. - zy Fy a, : ‘ oO. TEL.:. 950415 - TELEX: 20049 AQUAL LE -B.P.80I06 - BEYROUTH - UBAN =~ kK ee a +s {-a. Zu. I G)., we cil: My peo2e.jte Mees spustonn, 6-19, Onsane Vso as = 2O°C — f= 88%. 2B Ke} 3 I= 0.0005% a ae Pee Lorod . Re Oe — R= Uodt = 2yOA - 6C6.664 < 300 —> Qamnratr _ 4 ) © .2003 , . cord Rue dso Hobos | L —> ep. G10 velid « oid % ave (# un pe PP - 1.86 (Rey Pe) ca ; Nay = i ( Cy (s a) - Hes Mo = Pp (@ 0%) — 999.12«0- oo 32. 53\ 49464 = hd = 394973364 i . — My = Re o Co et a —> [Re 15.9448 oe} foo OO : a . . ~ Tid? q = Qa( Tet ~Ts)= m Co Gi, Tes) wa awe Pu, Us at , , rate 1.560% hte S45. 5 = RA (Tether Tas) = SB IIE. $3333 Warts (a pred tertiion ead De Dette Brit vk LL act Ppt sare). ar plan Mixed Conecilien prs ane 5 Ree Bo166 | . . FL, Pe dye 12.0216 1456 —> h- Rondel Gece. . 5) “Te = 20°C —»> aw Rack dren, cn. co forceck cose hun a eaten Re 0.585 Whee Pee 3.4 Pp 3 ale. Gays 10% fone, ol . Ka mE O ‘ 8 7) Gc?r = 6.34 «10 »(20-0)« 0.3" 34. 23G xlo . &.25) — Cc. ©o.)3 man Yy ~ Nag = 0113 (Ge Pr) ~ 31.4959 = ne > Re 6139S Yen > qs RA (Tote) = A Wal (Tote) [¢- 2 31169.0689 Wokts