100%(2)2 out of 2 people found this document helpful
This preview shows page 7 out of 7 pages.
different times during the cooling process. Draw three temperature profiles for (A) aluminum,and on a separate graph three temperature profiles for (B) cork. The three times you select shouldbe: t = 0 (before cooling), and two times during the cooling (but not at infinite time).Here, look up k for cork. Density and cp also change. All other variables stay the same.k = 0.039 (cork board--- NOT cork loose fill!)Bi = hLc/k = 10 * 0.001 / 0.039 =0.26. Although this is < 1, it is not sufficient to assumelumped capacitance, so the center of the sample will always be hotter than the surface.The temperature profiles are flat for aluminum. For cork, the profiles will be concave down,though the actual shape may be different that what is shown.Aluminum Temperature Profile010020030040050000.511.52Position (x, mm)Temperature (C)InitialTemperaturet= t1t = t2Cork Temperature Profile010020030040050000.511.52Position (x, mm)Temperature (C)InitialTemperaturet= t1t = t2