Injecting Water into Liquid Nitrogen Tanks
In this Demonstration, hot and cold water are injected into insulated tanks containing liquid nitrogen. The volume of water injected has a large impact on the amount of liquid nitrogen evaporated. Adjust the sliders to change the volume and temperature of water in each syringe, then click the play button. After equilibrium is reached, select the reset button to run the simulation for different starting conditions.[more]
The simulation may be paused at any time, and the animation speed may be increased or decreased using the up arrow and down arrow buttons. The simulation is at a much slower speed than the actual process in order to help visualize the process, and the volume of the ice cubes is exaggerated relative to the volume of the nitrogen gas.[less]
Contributed by: Neil Hendren (September 2019)
Additional Contributions by: John L. Falconer
(University of Colorado Boulder, Department of Chemical and Biological Engineering)
Open content licensed under CC BY-NC-SA
In an adiabatic system with excess liquid nitrogen, the mass of nitrogen vaporized depends on the mass of water injected , the specific enthalpy of the injected water and the final enthalpy of the water, which at equilibrium is the enthalpy of ice at :
where is the specific enthalpy of vaporization of nitrogen.
The difference between the initial and final specific enthalpies of water is the sum of the sensible heat changes and the heat of fusion of water ():
where and are the heat capacities of liquid water and ice, respectively, is the initial temperature of the water, is the freezing temperature of water (), and is , the boiling temperature of liquid nitrogen.
This Demonstration was inspired by an article by M. Prince et al. .
 M. Prince, M. Vigeant and K. Nottis, "Repairing Student Misconceptions in Heat Transfer Using Inquiry-Based Activities," Chemical Engineering Education, 50(1), 2016 pp. 52–61. journals.flvc.org/cee/article/view/87720.