Hello everyone! I am trying to design a magnetic testing apparatus that needs to remain at -196K for 20 minutes. There is not exactly a straight foreword equation to get a calculation for the evaporation rate of liquid nitrogen. The apparatus looks like this, and I have highlighted the area where the nitrogen will be located: The calculations that I have have been using are as follows: Is this equation accurate? Any advice would be appreciated. Equation source: http://en.wikipedia.org/wiki/Accidental_release_source_terms Thank you!