ONLY PART C is needed 10. (19.22) Nonsteady-state heat flow may be described by the following partial differential equ...
10. (19.22) Nonsteady-state heat flow may be described by the following partial differential equation эт ㄒㄧ 2 at where DT is the thermal diffusivity; this expression is the thermal equivalent of Fick's second law of diffiusion (Equation 5.4b). The thermal diffusivity is defined according to D_ k In this expression, k, p, and cp represent the thermal conductivity, the mass density, and the specific heat at constant pressure, respectively (a) What are the SI units for DT? (b) Determine values of DT for copper, brass, magnesia, fused silica, polystyrene, and polypropylene using the data in Table 19.1. Density values are included in Table B.1, Appendix B c) From the form of the governing partial differential equation, it should come as no surprise that the temperature distribution in a semi-infinite solid can be calculated from an equation which is analogous to equation 5.5 in the text Consider the case of a solid initially at 25C whose surface is suddenly heated to 125C. Calculate and plot the temperature profiles for the materials in part (b) at t-30 minutes after the surface is heated