Radiation heat transfer between parallel plates

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Discussion Overview

The discussion revolves around the calculation of radiation heat transfer between two parallel plates, specifically focusing on determining the final temperatures of the plates at steady state. Participants explore theoretical formulas, numerical simulations, and the complexities involved in heat transfer calculations.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant presents a formula for heat flux exchanged via radiation between two parallel plates, questioning how to calculate the final temperatures at steady state.
  • Another participant suggests that if the plates are thermally insulated, their temperatures will equilibrate, but thermal losses complicate the problem.
  • A participant proposes using heat transfer rate and specific heat to calculate temperature differences, but finds the results unsatisfactory compared to numerical simulations.
  • Some participants argue that the final temperature will be an average of the initial temperatures, while others challenge this simplification, emphasizing the need for algebraic solutions.
  • There is a suggestion to require energy flux to be equal and solve for temperature, with some participants expressing confusion about the necessary calculations.
  • One participant mentions that the equations indicate the net heat flow should be zero at equilibrium, raising concerns about the assumptions in the calculations.
  • A participant shares their experience with a finite element analysis simulation, seeking to validate the results against analytical calculations.

Areas of Agreement / Disagreement

Participants express differing views on the adequacy of the formulas used for calculating final temperatures, with some advocating for algebraic approaches while others question the assumptions made in the calculations. The discussion remains unresolved regarding the analytical prediction of final temperatures.

Contextual Notes

Participants note that the calculations may not account for heat exchange with the environment and that the assumptions about the system's isolation could affect the results. There is also mention of the complexity introduced by the plates' emissivities and heat capacities.

Who May Find This Useful

This discussion may be useful for individuals interested in heat transfer, thermal dynamics, and the application of radiation principles in engineering contexts.

  • #31
FEAnalyst said:
is there a way to calculate the final temperatures of the plates (in steady state, when the amount of heat known from above equation will be exchanged)?
##T_{final}## given ##T_1## and ##T_2## ? Stefan-Boltzmann equation : juggling, thereof.

For the two values given : 293.15K , 373.15K , the results of that (radiative) and the heat-conduction equation mentioned differ by ~2%.

Do the algebra first. Waaaay less messy.
 

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