A black thermocouple is inside a chamber with black walls. If the air around the thermocouple is at 20°C, the walls are at 100°C, and the heat transfer coefficient between the thermocouple and the air is 75 W/m²K, what temperature will the thermocouple read?

Troom = 25°C Problem-4: An 8-m-internal-diameter spherical tank made of 1.5-cm-thick stainless steel (k = 15 W/m-K) is used to store iced water at 0°C. The tank is located in a room whose temperature is 25°C. The walls of the room are also at 25°C. The outer surface of the tank is black (emissivity = 1), and heat transfer between the outer surface of the tank and the surroundings is by natural convection and radiation. The convection heat transfer coefficients at the inner and the outer surfaces of the tank are 80 W/m²-K and 10 W/m².K, respectively. Determine (a) the rate of heat transfer to the iced water in the tank and (b) the amount of ice at 0°C that melts during a 24-h period. The heat of the fusion of water at atmospheric pressure is hf5 333.7 kJ/kg. Iced water D D₁= 8 m Tin = 0°C 1.5 cm

A mercury-in-glass thermometer having a diameter of 6 mm is placed in a verti- cal position to measure the air temperature in a metal warehouse in the summer. The walls of the warehouse are at 50°C. The convection coefficient is 7 W/m² - °C, and the emissivity of the thermometer may be taken as € = 0.9. Calculate the temperature indicated by the thermometer if the air temperature is 32°C.

A thin board of 0.5 cm thickness is exposed to a fluid of T, = 22°C and h = 30 W/m².K from one side with an emissivity of 0.7 where it faces a surrounding whose temperature is Tsur = 30°C. A heat flux of q" = 3500 W/m? is applied to the other side. Each side has an area of 12cm×12cm. Tsur (a) If the board has the following properties: k = 15.1 W/m.K, c, = 480 J/kg.K and p = 8055 kg/m², express an equation for the variation of temperature with respect to time. (b) Find the initial time rate of change of the board temperature if the initial board temperature is q" h 50°C.