Heat flow in low pressure, knudsen number

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SUMMARY

This discussion focuses on heat transfer mechanisms in low-pressure environments, specifically within a vacuum chamber where the object is significantly smaller than the mean free path of air molecules. The participant seeks to understand the contributions of conduction and convection to heat transfer, noting that while radiation can be easily calculated, the effects of conduction and convection are less clear. The participant concludes that traditional models for molecular flow and viscous flow are not applicable due to the unique size and pressure conditions present.

PREREQUISITES
  • Understanding of mean free path in gas dynamics
  • Knowledge of heat transfer principles, including conduction and convection
  • Familiarity with vacuum systems and their properties
  • Basic principles of thermal radiation
NEXT STEPS
  • Research the Knudsen number and its implications for heat transfer in rarefied gases
  • Explore the effects of thermal conductivity in low-pressure environments
  • Study the principles of gas kinetic theory as they relate to heat transfer
  • Investigate computational fluid dynamics (CFD) simulations for modeling heat transfer in vacuum conditions
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Researchers, engineers, and physicists involved in thermal management, vacuum technology, and heat transfer analysis in low-pressure systems.

Flanders3
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Hi! Been lurking around here for a while but joined today :)

My question is about heat transfer in low pressures. I have an object in a vacuum chamber that is much smaller than the mean free path of the air in the chamber. However, the general dimensions of the chamber are much larger than the air mean free path. Heat radiation from the object is easy to calculate but how about conduction/convection to the surrounding air? I'm pretty sure it is low, but how low?
 
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I thought i couldn't use molecular flow because the air in the chamber is viscous, but I can't use viscous flow either because the air molecules are so likely to 'miss' the heated object.
 

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