The boiling temperature of nitrogen at atmospheric pressure at sea level (1 atm pressure) is -196 °C. Therefore, nitrogen is commonly used in low-temperature scientific studies since the temperature of liquid nitrogen in a tank open to the atmosphere will remain constant at -196 °C until it is depleted. Any heat transfer to the tank will result in the evaporation of some liquid nitrogen, which has a heat of vaporization of 198 kJ/kg and a density of 810 kg/m3 at 1 atm. Consider a 3-m-diameter spherical tank that is initially filled with liquid nitrogen at 1 atm and -196 °C. The tank is exposed to ambient air at 15° C, with a combined convection and radiation heat transfer coefficient of 35 W/m2⋅K. The temperature of the thin-shelled spherical tank is observed to be almost the
The boiling temperature of nitrogen at atmospheric pressure at sea level (1 atm pressure) is -196 °C. Therefore, nitrogen is commonly used in low-temperature scientific studies since the temperature of liquid nitrogen in a tank open to the atmosphere will remain constant at -196 °C until it is depleted. Any heat transfer to the tank will result in the evaporation of some liquid nitrogen, which has a heat of vaporization of 198 kJ/kg and a density of 810 kg/m3 at 1 atm.
Consider a 3-m-diameter spherical tank that is initially filled with liquid nitrogen at 1 atm and -196 °C. The tank is exposed to ambient air at 15° C, with a combined convection and radiation heat transfer coefficient of 35 W/m2⋅K. The temperature of the thin-shelled spherical tank is observed to be almost the same as the temperature of the nitrogen inside. Determine the rate of evaporation (in kg/s) of the liquid nitrogen in the tank as a result of the heat transfer from the ambient air if the tank is insulated with 5-cm-thick fiberglass insulation (k = 0.035 W/m⋅K).
Trending now
This is a popular solution!
Step by step
Solved in 2 steps with 2 images
