Evaporation Rate of Liquid Nitrogen

In summary: So, in summary, the equation you are using is accurate but may not give you the exact rate of evaporation for your specific situation. It is important to consider other factors such as container size and shape, temperature, heat transfer, and frequency of refilling when calculating the evaporation rate of liquid nitrogen in your magnetic testing apparatus.
  • #1
porkchop-sand
1
0
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:

fnWUw.jpg


The calculations that I have have been using are as follows:

7G1W8.jpg


Is this equation accurate? Any advice would be appreciated.
Equation source: http://en.wikipedia.org/wiki/Accidental_release_source_terms

Thank you!
 
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  • #2
Yes, the equation you are using is accurate. However, it is important to note that this equation may not give you the exact rate of evaporation for your specific situation. There are a few other factors that you should take into consideration when calculating the evaporation rate of liquid nitrogen in your apparatus. These include the size and shape of the container, the temperature of the container, and the rate of heat transfer from the container to the atmosphere. Also, the rate of evaporation will depend on how often you open the container to refill it with liquid nitrogen. All of these factors can affect the rate of evaporation and should be taken into account when calculating the evaporation rate of liquid nitrogen in your apparatus.
 

1. What is the evaporation rate of liquid nitrogen?

The evaporation rate of liquid nitrogen varies depending on the surrounding temperature and pressure. At room temperature (20°C), the evaporation rate is approximately 0.2 liters per hour for an open container. However, in a closed container, the evaporation rate will be significantly slower.

2. What factors affect the evaporation rate of liquid nitrogen?

The evaporation rate of liquid nitrogen is affected by temperature, pressure, surface area, and container type. Higher temperatures and lower pressures will result in a faster evaporation rate. A larger surface area, such as in an open container, will also increase the evaporation rate. The type of container can also impact the evaporation rate, with non-insulated containers having a higher rate compared to insulated ones.

3. How is the evaporation rate of liquid nitrogen measured?

The evaporation rate of liquid nitrogen can be measured using a variety of methods, such as a graduated cylinder, a flowmeter, or by weighing the container before and after a certain time period. The most accurate method is to weigh the container, as it takes into account any changes in pressure and temperature.

4. What is the purpose of knowing the evaporation rate of liquid nitrogen?

Knowing the evaporation rate of liquid nitrogen is important for safely handling and storing the substance. It can also be useful in industrial and scientific applications, such as cryogenic freezing and cooling processes. Additionally, understanding the evaporation rate can help in determining the appropriate storage and handling methods to minimize waste and costs.

5. Can the evaporation rate of liquid nitrogen be controlled?

Yes, the evaporation rate of liquid nitrogen can be controlled by managing the temperature, pressure, and surface area. Keeping the liquid nitrogen at lower temperatures and higher pressures, as well as reducing the exposed surface area, can slow down the evaporation rate. Additionally, using insulated containers and proper storage techniques can also help control the evaporation rate.

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