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Tutorial # 3 WWWR #18.12 (additional data: h = 6W/m 2 -K), 18.2, 18.4, 18.19, 18.15, 18.23. To be discussed during the week 3-7 Feb., 2014. By either volunteer or class list. Homework # 3 (Self practice) WWWR #18.18, 18.27. ID # 5.6, 5.9. HW #3 /Tutorial # 3 WWWR Chapter 18 ID Chapter 5.
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Tutorial # 3 WWWR #18.12 (additional data: h = 6W/m2-K), 18.2, 18.4, 18.19, 18.15, 18.23. To be discussed during the week 3-7 Feb., 2014. By either volunteer or class list. Homework # 3 (Self practice) WWWR #18.18, 18.27. ID # 5.6, 5.9. HW #3 /Tutorial # 3WWWR Chapter 18ID Chapter 5
Spherical metallic specimen, initially at uniform temperature, T0 Energy balance requires
Large value of Bi • Indicates that the conductive resistance controls • There is more capacity for heat to leave the surface by convection than to reach it by conduction Small value of Bi • Internal resistance is negligibly small • More capacity to transfer heat by conduction than by convection
Example 1 (WWWR Page 266) • A long copper wire, 0.635cm in diameter, is exposed to an air stream at a temperature of 310K. After 30 s, the average temperature of the wire increased from 280K to 297K. Using this information, estimate the average surface conductance, h.
Heating a Body Under Conditions of Negligible Surface Resistance
IC BC(1) BC(2) V/A = (WHL)/(2WH)=L/2 BC (1) -> C1=0 BC (2) -> l = np/L Fo = at/(L/2)2 IC -> Fourier expansion of Yo(x) …..> Equation (18-12) Engineering Mathematics: PDE
Detailed Derivation for Equations 18-12, 18-13 Courtesy by all CN5 students, presented by Lim Zhi Hua, 2003-2004
Detailed Derivation for Equations 18-12, 18-13 Courtesy by all CN5 students, presented by Lim Zhi Hua, 2003-2004
WWWR 18-12; 18-13 WWWR 18-16 (a) T=Ts @ x =0 WWWR 18-20 (b) -k dT/dx = h (T-T∞) @ x =0 WWWR 18-21
Courtesy contribution by ChBE Year Representative, 2006.