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I'm trying to design a cooling system for cooling nitrogen at 300°C. My original design (which is very open to modifications) is an aluminum ring block with exterior fins and vertical holes through the block connected end to end to form a continuously undulating gas line. An amazing engineer proposed flowing the gas through multiple holes simultaneously to address the pressure drop problem along the original single gas line, but any better approach is encouraged. My design operates by submerging the block into a water the size an Olympic swimming pool at 20°C. 468 g of nitrogen driven out of a vessel originally pressurized to ~5000 psi goes through the cooling system in roughly 10 seconds. The aim is to be able to cool the nitrogen down to 25°C as it exits the cooling system at that staggering flow rate.

What mass, geometry, and feature of the aluminum block, and/or modifications to the original design is required to achieve the stated aim.

TechDroid
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  • I don't understand why you don't use a suitable off-the shelf heat exchanger. Is this a continuous or a batch process? To what pressure will the nitrogen vent, why does adiabatic cooling not suffice. Also where's the sketch of your original design. – mart Feb 20 '19 at 16:01
  • Also, without sounding harsh, are you qualified to design and build equipment for these pressures? – mart Feb 20 '19 at 16:02
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    @mart have a look at this question then answer your own... https://engineering.stackexchange.com/q/25985/10902 – Solar Mike Feb 20 '19 at 16:19
  • That's because off-the-shelf isn't suitable for the context of operation of the device. I don't understand what you mean by batch or continuous process, it'll kind of you to explain. ~120 psi. Adiabatic cooling isn't suited to the application, the system isn't meant to be powered nor concealed. I'm not sure the sketch is necessary, it can be easily pictures from the above description. – TechDroid Feb 20 '19 at 16:27
  • I opened this new post to further put the situation in a more design oriented state. The answers in the post https://engineering.stackexchange.com/questions/25985/cooling-hot-nitrogen-with-an-aluminum-block doesn't answer this questions given all the new information. – TechDroid Feb 20 '19 at 16:34
  • Adiabatic expansion will cool the gas to 128K (-144°C). Techdroid are you sure you know what your are talking about and that you understand basic thermodynamics? Other users: Feel free to correct me if I'm wrong. – mart Feb 20 '19 at 16:51
  • I'm voting to close this question as off-topic because it appears to be based on utterly wrong premises. – mart Feb 20 '19 at 16:52
  • Why do you have to vote a close so soon, if I wasn't looking for answers why would I ask. It won't hurt to explain your idea better if I don't understand. I never thought it that way actually. If you don't mind Mart, explain how the adiabatic cooling will work in this context. – TechDroid Feb 20 '19 at 17:02
  • Techdroid: Simply look up adiabatic processes, expanding a gas (= lowering presure) will cool it. The math is explaned somehwere on the relevant wikipedia page. – mart Feb 20 '19 at 19:51
  • I did right at the moment you mentioned it, and I've been exploring, but in my case I'm venting a high pressure hot nitrogen tank through a tube, there is no volume change only pressure drop based on Bernoulli's principle. How do you envision this to operate. – TechDroid Feb 20 '19 at 20:17
  • When pressure drops, the gas expands. When pressure drops from 5000 psi to 120, the gas expands very much. You need a thermodynamics textbook, or better a class. I'm not willing to give one. – mart Feb 21 '19 at 07:24
  • Thanks a lot for that. I do understand the concept no problem, but in the practical sense, does the gas venting and moving along the tube from a 5000 psi tank cools all by itself as it moves further through the tube? Does it work like that? – TechDroid Feb 21 '19 at 08:47

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