Energy Conversion With Supercritical Fluids

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SUMMARY

The discussion focuses on the conversion of thermal energy into kinetic energy using supercritical CO2 within a closed figure-8 loop system. It emphasizes the relationship between temperature, pressure, and the state of matter in achieving supercritical conditions. The participants clarify misconceptions regarding supercritical fluids and superfluids, highlighting that while supercritical fluids exhibit low viscosity, they are not frictionless. The conversation concludes with a reference to a research paper that addresses the dynamics of supercritical fluids after thermal energy introduction.

PREREQUISITES
  • Understanding of supercritical fluid dynamics
  • Knowledge of thermodynamics principles, particularly heat transfer
  • Familiarity with the properties of CO2 under varying pressure and temperature
  • Basic grasp of fluid mechanics and viscosity concepts
NEXT STEPS
  • Research the thermodynamic properties of supercritical CO2
  • Study the principles of heat transfer in closed systems
  • Explore the differences between supercritical fluids and superfluids
  • Investigate methods for measuring kinetic energy in supercritical fluid systems
USEFUL FOR

Engineers, physicists, and researchers interested in thermal energy conversion, fluid dynamics, and the applications of supercritical fluids in energy systems.

Benign Paradigm
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Technically, this isn't a question concerning supercritical fluids. It's more about converting thermal energy into velocity by playing "keep-away" with molecules that want to go supercritical.

The idea is simple. In an fully contained system, we can more or less say volume is static. Temperature becomes what determines both pressure and state of matter once we have that system of static volume. We can now simulate the introduction and removal of thermal energy.

Let's say our system is a figure-8 loop and contains CO2 at the right pressure to invoke a super-critical state relatively near to ambient external temperatures. We can now introduce a low-energy heat source to generate a state change with relative ease. As the CO2 begins to go supercritical, we can introduce a low-energy source of cooling to from outside of this closed system, as well.

What I'd like to know is how to describe the transfer of this energy. It seems to me, that an unnaturally large portion of the thermal energy we introduce will be converted directly into kinetic energy until it leaves the system as thermal energy again on the "cooling side" of our figure-8.

I'm trying to determine the potential velocity of molecules within this system, based on the differential between my source of heat and my heat absorption. I'm just not sure exactly how to go about such a thing. Supercritical fluids are purportedly frictionless, but a system that is very nearly supercritical should be very nearly frictionless correct?

If that's the case, shouldn't it be hypothetically possible to generate extreme velocities within this system by increasing both the heat source and heat absorption rates to high levels?

And if so, how do we trend these rates to accurately achieve a desired velocity?
 
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Benign Paradigm said:
Supercritical fluids are purportedly frictionless, but a system that is very nearly supercritical should be very nearly frictionless correct?
In a word? "No."
 
Bystander said:
In a word? "No."
My understanding was that matter in the containment will reach greater velocities than it normally would, if the rest of the volume is near to reaching a supercritical state.

Judging by the simplicity of your answer, am I to assume that I'm completely wrong?
 
You have confused "supercritical" with "superfluid," as in He II is a low/zero viscosity "superfluid."
 
I see. I was taught that an entire volume must be undergo the change to a super-critical state in order for the super-critical fluid to be relaxed. For that reason, I drew a parallel to super fluids. I was with the impression that matter undergoing the change to a super-critical state would increase in velocity to transfer heat out of the volume by exhibiting the same defiance of friction.

I think I found a paper that'll adequately answer my mangled question. Maybe you'll be interested.

https://www.researchgate.net/profile/Pierre_Carles3/publication/235528431_Relaxation_of_a_supercritical_fluid_after_a_heat_pulse_in_the_absence_of_gravity_effects_Theory_and_experiments/links/00b49537191b169ed3000000.pdf
 
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Thankee.
 

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