Please use Fundamentals of Heat and Mass Transfer (8th Ed.), by
Bergman, Lavine, Incropera and DeWitt, Wiley as a resource.
**PLEASE show all work for all steps and use formulas from the
book listed above**
**PLEASE do all parts of question **
J. Determine the outer surface temperature Ts,o of the window
using your answers from parts G and H in ï‚°C.
A window of an automobile is defogged by passing warm air over its inner surface. The window glass is 4 mm thick. Over an inner surface of the window, air temperature is T; = 40C; inner window surface temperature is Tsi; and the corresponding convection coefficient is hi = 3o W/(m2-K). Outside the automobile, air temperature is T,o = -10C; outer window surface temperature is Ts,o; and the associated convection coefficient is ho = 65 W/(m2-K). The schematic below illustrates the situation. Assume that it is steady state, there is no internal heat generation within the window, and the associated heat transfers is one-dimensional.
Glass
Ts.i
T=-10OC ho=65W/m2K
q
Ti=40C h=30W/m2K
L=0.004m
A. Starting from an original form of heat diffusion equation (equation 2.19 in your textbook), derive a heat diffusion equation that includes ONLY relevant terms of this problem. List at least two assumptions that are necessary when simplifying the original heat diffusion equation. You may assume that the thermal conductivity is constant within the glass. B. Write the boundary conditions at inner and outer surfaces of the window that are required to solve of the heat diffusion equation. C. of your textbook. Indicate the temperatures (T,;, Ts, T,o, Ts,o), thermal resistances based on heat flux, and heat flux in the circuit diagram. Do NOT need to perform any calculations in this part. D. What is the thermal conductivity of the glass (soda lime plate) at 300K? Use the table in your textbook appendix A. E. Determine the thermal resistance based on heat flux across the window Rt,w (that is conduction thermal resistance based on heat flux). F. Determine the thermal resistance based on heat flux over the inner surface of the window R'ti (that is convection thermal resistance based on heat flux). G. Determine the thermal resistance based on heat flux over the outer surface of the window Rt,o (that is convection thermal resistance based on heat flux). H. Determine the heat flux (not heat rate in W) through the window in W/m2. Use the thermal resistances that you obtained in parts E, F, G.
parts F and H in C.
