In: Physics
Air at 15°C flows at 9 m/s parallel to a thin flat plate measuring 260 mm × 390 mm. The direction of flow is parallel to the 260-mm edges. The surface of the plate is at a uniform temperature of 85°C. The plate is in a large chamber with walls at a temperature of 22°C. The emissivity of the plate’s surfaces is 0·75. (a) Determine the rate of convective heat transfer from one side of the plate to air. [16] (b) Determine the rate of radiant heat transfer from one side of the plate the chamber walls. [4] (c) In the configuration described above, consider two values of freestream air speed: 9 m/s and 100 m/s. Sketch a graph showing the variation of local heat flux q'' (x) as a function of distance x along the plate from the leading edge for each value of speed, showing the two curves on a single set of axes. It is not necessary to calculate values for q'' (x) but you should determine the correct shape of each curve. Briefly explain the reasons for differences between the curves.