Heat transfer to ice under vacuum
Heat transfer to ice under vacuum
(OP)
Hello all,
I am trying to solve a sublimation/heat transfer problem and could use some help from you.
I have a freeze dryer under vacuum at a pressure of say 0.1 mbar. The temperature of the ice in the dryer is say -20 degree centigrade (253 Kelvin). To assist sublimation, I am providing heat to the stainless steel jacket wall of the dryer at say 30 degree centigrade (303K).
The jacket area is 3 m2
Now I would like to increase the temperature of the jacket wall to 40 degrees (313 K). How can I determine what the new ice temperature will be?
I am trying to solve a sublimation/heat transfer problem and could use some help from you.
I have a freeze dryer under vacuum at a pressure of say 0.1 mbar. The temperature of the ice in the dryer is say -20 degree centigrade (253 Kelvin). To assist sublimation, I am providing heat to the stainless steel jacket wall of the dryer at say 30 degree centigrade (303K).
The jacket area is 3 m2
Now I would like to increase the temperature of the jacket wall to 40 degrees (313 K). How can I determine what the new ice temperature will be?





RE: Heat transfer to ice under vacuum
Take the equation that you used for the first case and substitute the new wall temp.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Heat transfer to ice under vacuum
Thanks for your response
The first value are assumptions of the state of the system and not calculated - so I have no equation.
Secondly, I feel conduction from the wall to the ice is the dominant heat transfer mechanism and radiation is minimal. The ice is in contact with the wall.
RE: Heat transfer to ice under vacuum
In my experience the ice that forms in these is very low density and has poor heat transfer properties, it is almost an insulator.
But you should be able to estimate an increase in Q and the resulting temps.
= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube
RE: Heat transfer to ice under vacuum
RE: Heat transfer to ice under vacuum