When traveling by airplane the air temperature at high altitudes can be very

When traveling by airplane the air temperature at

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6. When traveling by airplane, the air temperature at high altitudes can be very low. Assume that the fuselage (passenger compartment) can be approximated as a cylinder that is 70 m long and has an outer diameter of 6 m. Ignoring the windows, the fuselage is made up of two components: an inner insulation layer made of plastic with k = 0.78 W/m-K and thickness of 0.05 m. Outside of that is an aluminum layer that is 0.010 m thick, which is exposed to the outer air. The inside air is kept comfortably at 22 oC during flight, while the temperature in the upper atmosphere reaches -35 oC. The convective heat transfer coefficient for the internal air is 12 W/m2-K. Outside, the forced convection coefficient is 650 W/m2-K. You may ignore the front and tail of the airplane, and only consider heat transfer from the curved edge of the cylinder. You’ll need the appendix to find kAl. A. Draw a thermal resistance diagram, indicating & labeling each resistance to heat transfer between the internal (cabin) air and the outside air. B. Determine the rate that energy must be added to the cabin (in Watts) so that the 22 oC temperature doesn’t drop during high-altitude flight. C. What is the heat flux, q” on the inside surface of the airplane? What is the heat flux on the outside surface? R4 2 2
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