Is there a way to model a pipe under vacuum pressure using Simscape?
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Is there a way to model fluid flow in a pipe under vaccum pressure using simscape?
2 Comments
Yifeng Tang
on 18 Jun 2021
Hey Delika,
Could you please elaborate on your question? What do you mean by "vacuum"? Is there still some air left in the "vacuum"? Will the liquid evaporate to fill the vacuum? A simple diagram would be very helpful.
Answers (1)
Yifeng Tang
on 19 Jun 2021
Hey Delika,
Thanks for the clarification.
It seems to me that it's possible to model the evaporation and condensing effects at two ends of a heat pipe, using blocks from the two-phase (2P) domain. It may not be easy though.
Couple blocks that I think may be useful for you:
Receiver Accumulator (2P) https://www.mathworks.com/help/releases/R2020a/physmod/hydro/ref/receiveraccumulator2p.html This one will allow you to model the two ends of the heat pipe. I suggest this instead of a simple chamber, because you need a way to allow only the liquid phase to travel away from the cold end through wicking, and gas phase away from the hot end (by pressure?). This block gives you the option to do that. The thermal port will allow you to heat or cool the fluids.
Pipe (2P) https://www.mathworks.com/help/releases/R2020a/physmod/simscape/ref/pipe2p.html You need pipes to tranport fluid (vapor & liquid) between the two ends.
What I am not sure or clear about is how to model the wicking of liquid from the cold end to the hot end. Any correlation you are aware of for the capilliary effect that's driving the flow? You'll need to find a way to implement that on the liquid path. The vapor path, I think, will be driven by the pressure difference because the hot end will have a higher vapor pressure.
Your model could conceptually look like this:![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/658195/image.jpeg)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/658195/image.jpeg)
Hope this helps.
6 Comments
Yifeng Tang
on 16 Jul 2021
I think I see the confusion here. The proper way to set the pressure inside the heat pipe is through initial conditions. Look for the "variables" tab in each block; that's where you set the initial condition for each block. I don't think you'll need any source connected to the "outside" to enforce a specific pressure inside the heat pipe, as the pressure source can lead to flow in or out of the sealed system. Once you set a reasonable initial condition, the total mass inside the heat pipe will be conserved.
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