Thermal Diffusivity in practice

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SUMMARY

This discussion focuses on estimating heat flow between two gases separated by a wall in a heat exchanger, emphasizing the role of thermal diffusivity. The user seeks to apply thermal diffusivity values, typically expressed in mm²/sec, to their specific scenario, which involves diffusion through the wall's thickness. They note the assumption of uniform temperature across the wall's surface, simplifying the analysis. Additionally, the user considers using electrical analogs for thermal diffusivity but struggles to find a suitable comparison.

PREREQUISITES
  • Understanding of thermal diffusivity and its units (mm²/sec)
  • Knowledge of the 1D heat equation and boundary conditions
  • Familiarity with heat exchangers and gas dynamics
  • Basic concepts of electrical analogs in thermal systems
NEXT STEPS
  • Study the application of the 1D heat equation in heat transfer scenarios
  • Research methods for calculating heat flow using thermal diffusivity
  • Explore electrical analogs for thermal systems, focusing on circuit simulation tools
  • Investigate the impact of wall thickness on heat transfer rates
USEFUL FOR

Engineers, physicists, and researchers involved in thermal management, heat exchanger design, and heat transfer analysis will benefit from this discussion.

mynode
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I have a system with two gasses separated by a wall as in a heat exchanger. One of the gasses changes temperature by the action of an outside agent and I'm trying to estimate the heat flow between the two gasses over time.
I know that thermal diffusivity is a factor in this, but I don't know how to apply the numbers given for it to my situation. The units for thermal diffusivity are something like mm2/sec. I can assume that the temperature over the surface of the wall is uniform, so I don't have to worry about diffusion in those dimensions, but I do need to account for diffusion through the thickness of wall. I would expect to need a factor in mm/sec, but I have mm2/sec.
Also, I was thinking that an electrical analog might make this easier to analyze as I have access to programs for simulating electrical circuits, but I can't find a definite analog for thermal diffusivity.
 
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solve the 1D heat equation subject to your specific boundary conditions. The thermal diffusivity is the factor in front of del^2 T
 

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