1. Consider the flow of air with a temperature of 21C (Cp = 1004.8 J/kg*K, v=1.5x10^(-5)...

 

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1. Consider the flow of air with a temperature of 21C (Cp = 1004.8 J/kg*K, v=1.5x10^(-5) m2/s, k=0.025 W/M*K, Pr=0.7) at a velocity of 3 m/s over a flat plate. The plate has a thermal conductivity k=33 W/m*K, surface temperature Ts=58C, width = 1m, and length = 1.2 m. a. Calculate the heat flux at 0.3 m from the leading edge of the plate. b. Calculate the heat transfer coefficient at the end edge of the plate. c. Calculate the rate of heat transfer over the whole length of the plate 2. Air with a mass rate of 0.075 kg/s flows through a tube of diameter D=0.225 m. The air enters at 100C and, after a distance of L=5m, cools to 70C. Determine the heat transfer coefficient of the air. The properties of air at 85C are approximately Cp = 1010 J/kg*K, k= 0.030 W/m*K, = 208x10^(-7) N*s/m2, and Pr = 0.71. 3. A 10-centimeter inner diameter spherical ball contains ice at O C. The sphere walls are 1 centimeter thick and made from PVC (k=0.18 W/mk). If the outside temperature is 40 C and the air convection coefficient is 30 W/m^2k, how long would it take for the ice to melt? (Hint: We will need the density and volume of the ice to determine its mass). 1. Consider the flow of air with a temperature of 21C (Cp = 1004.8 J/kg*K, v=1.5x10^(-5) m2/s, k=0.025 W/M*K, Pr=0.7) at a velocity of 3 m/s over a flat plate. The plate has a thermal conductivity k=33 W/m*K, surface temperature Ts=58C, width = 1m, and length = 1.2 m. a. Calculate the heat flux at 0.3 m from the leading edge of the plate. b. Calculate the heat transfer coefficient at the end edge of the plate. c. Calculate the rate of heat transfer over the whole length of the plate 2. Air with a mass rate of 0.075 kg/s flows through a tube of diameter D=0.225 m. The air enters at 100C and, after a distance of L=5m, cools to 70C. Determine the heat transfer coefficient of the air. The properties of air at 85C are approximately Cp = 1010 J/kg*K, k= 0.030 W/m*K, = 208x10^(-7) N*s/m2, and Pr = 0.71. 3. A 10-centimeter inner diameter spherical ball contains ice at O C. The sphere walls are 1 centimeter thick and made from PVC (k=0.18 W/mk). If the outside temperature is 40 C and the air convection coefficient is 30 W/m^2k, how long would it take for the ice to melt? (Hint: We will need the density and volume of the ice to determine its mass).

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