radiation 2

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Radiation Heat Transfer e = emissive power G = total irradiation J = total radiosity 1 In general: Opaque material: 1 = absorptivity = reflectivity = transmissivit = emissivity

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radiation

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  • Radiation Heat Transfere = emissive powerG = total irradiationJ = total radiosityIn general:Opaque material:a = absorptivityr = reflectivityt = transmissivitye = emissivitya=e

  • lelEnergyIdeal EmitterSchematicT3> T2> T1

  • Radiation Heat TransferBlack Bodyabsorptivity = a=1emissivity = e=1ideal emissive power = ebGray Bodyabsorptivity < 1emissivity < 1emissive power
  • lelEnergySchematic

  • Radiation Heat TransferThermal EquilibriumView Factor: Fij = fraction of radiation from surface i intercepted by surface j.

  • Radiation Heat TransferNo net heat flux wallAnalog circuitFind:

  • Radiation Heat Transfer

  • Radiation Heat Transfer

  • Radiation Heat Transfer

  • Radiation Heat Transfer

  • Radiation Heat TransferConsider the radiation heat transfer between two infinite parallel plates.Special Case

  • Radiation Heat TransferConsider the radiation heat transfer between a small object and infinite surroundings.1SSpecial Case