Problem 1:
Aluminum nitride fins (k = 171 W/m· K) are commonly used to dissipate heat from electronic devices. An example of such a fin is shown in the accompanying figure. Using ANSYS, determine the temperature distribution within the fin and indicate the maximum and minimum temperatures and their locations. The base of the fin experiences a constant flux of q' = 1000 W/m. A fan forces air over the surfaces of the fin. The temperature of the surrounding air is 20oC with a corresponding heat transfer coefficient of h = 40 W/m2·K.
Problem 2:
Hot water flows through pipes that are embedded in a concrete slab. A section of the slab is shown in the accompanying figure. The temperature of the water inside the pipe is 50°C, with a corresponding heat transfer coefficient of 201 W/m2·K. With the conditions shown at the surface, use ANSYS to determine the temperature of the surface and indicates the lowest temperature and it locations. Assuming that the heat transfer coefficient associated with the hot-water flow remains constant; find the lowest water temperature at which the surface is not freezes (the temperature on the surface is a little above 0oC). Neglect the thermal resistance through the pipe walls. The thermal conductivity for the concrete slab is 1.7 W/m·K.
Problem 3:
Considering the heat transfer model shown in the accompanying figure, determine the temperature distributions in the wall, the floor, and the soil and indicate the maximum and minimum temperatures and their locations, and the heal loss from the floor and the wall. As shown in the figure, assume that at about four feet away from the wall and the floor, the horizontal and the vertical components of the heat transfer in the soil become negligible. The thermal conductivity for soil is 0.31 Btu/hr·ft·oF and 0.61 Btu/hr·ft·oF for concrete.