solution4 - An aluminum can having the diameter of6 cm and...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2.
Background image of page 2
Background image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: An aluminum can having the diameter of6 cm and the height of 10 cm contains fruitjuice at 1“C. Using a lumped-capacity analysis, estimate the time required for the contents to warm to 15“C when the can is placed in a room at 22°C with a convection coefficient of4 Wltn 2 “Cl Assume the fruitjuice has the same properties as water. Also validate the assumption ofthe lumped—capacity analysis employed. 999a duds P g ' c = 42.2.5 - k' n 0's; L: 0.! A: ald‘KL'f'leJ— zonal-+5 M V “ fidtL. "' 0 9092.85 M3 3 = )3:— = bani; AV = 4. I: 0"“; ‘—' [La gun-s P‘- 9&9} x +1.15 K «Lu- 1&3 T— T9. is — [L t-- 5.3-0 Incl-r4: 1LT... ' I -1-L 't. 2. laaqa' S 3"- 3.?‘11-1 .- ‘i- Knows 0.3!- Chadv. : 51 3%: =c.as-t <0" A concrete column (an infinite circular cylinder) with radius 1"” = 0.3 m initially has a uniform temperature of 30"C. Now the atmospheric environment is suddenly changed to 20°C. The convection heat transfer coefficient is estimated to be 5 Who 2 DC. What will be the temperatures ofthe concrete at r = 0.0 (center) and 0.3 m (surface) after 24 hours? The properties ofthe concrete are as follows: a = 7 x10 ‘7 m l is and k = l W/m.°C. NOTE: For a cylinder with a convection boundary, the one—term approximation is given as follows: T —‘ Tab 2 I” T; _ T1, = Cl Fl) )Jn (4] The values for Bessel function are given in Table 8.4. Bi- -— hr- _ §X°.3 K I =l.§' Fm 'hblgf-l’ cl = |_¢.l.?_;; (;I = Lay-zit db 4“. a! LEI-$364. r... =- °.6?L 70.1. 1'... To. _ T-- 3-6 I Lam‘s u ( tH‘H4L b > —-——. -. = . - . X 0. $2» = T14.” and P 0.32.35 T(r=e) = goat. tuko,3l3$ : L3.z'c_ 4 Io<§| '0‘? = ELIA-ZWJ = angler. : 0.32.3: wast-ti- = all-HS TLr:o.3) = Llfil-‘L o On a hot summer day a concrete driveway may reach a temperature of SOT. Suppose that a stream ofwater is directed on the driveway so that the surface temperature is suddenly lowered to 20°C. How long will it take to cool the concrete to 30°C at a depth of 5 cm From the surface? {A = ? x-ahf M75 T1: 561C , T; =- z-o'c. Tts.a9.t) : 33'; T- 1-; _ 35‘ ~19 T1 :1: ~ e.» ‘24:! 2 0'55” : eff & i: ‘6er E '—" 950‘“: 95° oszfé-j 2 x = “.5 D. 5&- use-9:3 ngt ;J ?A|5+t t= 9543 5‘ ...
View Full Document

Page1 / 3

solution4 - An aluminum can having the diameter of6 cm and...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online