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flow noshield

Computes the radiative heat flow between two plane surfaces that are separated by a non-absorptive medium.
Controller: CodeCogs

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Flow Noshield

 
doubleflow_noshielddoubleT1
doubleT2
doublee1
doublee2 )[inline]
This module calculates the radiative heat flow per unit surface between two plane surfaces, considering the case when these are separated by a non-absorptive medium.

On account of the Stefan-Boltzmann law, the unit radiative heat flow between the two surfaces is given by where with e_1, e_2 the emissivity factors of the first and second surface (0 < e_1, e_2 \leq 1), C_0 the emissivity constant of the black body \displaystyle \left(C_0 \approx 5.669 \left[\frac{W}{m^2 K^4}\right]\right) and T_1, T_2 the corresponding absolute temperatures of the two plane surfaces.

In the diagram below is show the radiative heat transfer between two plane surfaces, in which E_1 is the radiative energy emitted by the first surface, E_2 is the radiative energy emitted by the second surface, A_1 is the energy emitted by the first surface and absorbed by the second, A_2 is the energy emitted by the second surface and absorbed by the first, R_1 is the radiative energy emitted by the first surface and reflected by the second and R_2 is the radiative energy emitted by the second surface and reflected by the first.

1/flow_noshield-378.png
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Example 1

The example below computes the unit radiative heat flow between an oxidated aluminium plane surface at 873.16 degrees Kelvin and an oxidated copper plane surface at 403.16 degrees Kelvin, separated by a non-absorptive medium.
#include <codecogs/engineering/heat_transfer/radiation/flow_noshield.h>
#include <stdio.h>
 
int main()
{
  // the temperature of the oxidated aluminium surface
  double T1 = 873.16;
 
  // the temperature of the oxidated copper surface
  double T2 = 403.16;
 
  // the emission factor of the aluminium surface
  double e1 = 0.19;
 
  // the emission factor of the copper surface
  double e2 = 0.76;
 
  // display radiative heat flow between the two plane surfaces
  printf("Radiative heat flow = %.5lf W per sq. meter\n",
  Engineering::Heat_Transfer::Radiation::flow_noshield(T1, T2, e1, e2));
 
  return 0;
}

Output

Radiative heat flow = 5638.04033 W per sq. meter

Note

A table with the emissivity factors of various materials at different temperatures can be found at the following link http://www.monarchserver.com/TableofEmissivity.pdf

References

Dan Stefanescu, Mircea Marinescu - "Termotehnica"

Parameters

T1the absolute temperature of the first surface (Kelvin)
T2the absolute temperature of the second surface (Kelvin)
e1the emissivity factor of the first surface
e2the emissivity factor of the second surface

Returns

the radiative heat flow between the two plane surfaces (Watt per square meter)

Authors

Grigore Bentea, Lucian Bentea (November 2006)
Source Code

Source code is available when you buy a Commercial licence.

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