Interface
#include <codecogs/engineering/heat_transfer/radiation/energy.h>
using namespace Engineering::Heat_Transfer::Radiation;
| double | energy (double T, double e = 1.0)[inline] Computes the total energy radiated by a body with given parameters. |
 | Real | cc_energy (Real T, Real e ) This function is available as a Microsoft Excel add-in. |
Function Documentation
This module calculates the total energy radiated by a body per unit surface area in unit time.
The total radiative energy

of a black body is given by the Stefan-Boltzmann law
where

is the radiative intensity of the black body.
In practice, the following formula due to Kirchoff is used
where

is the emissivity constant of the black body
![\displaystyle \left(C_0 \approx 5.669 \left[\frac{W}{m^2 K^4}\right]\right) \displaystyle \left(C_0 \approx 5.669 \left[\frac{W}{m^2 K^4}\right]\right)](/latexrender/sites/unknown/2ea69a509f4d5e564f4f688208aecc96.gif)
,

is the emissivity factor of the body

and

is its absolute temperature.
Example:
- The following example calculates the total radiative energy emitted by the Wolfram filament of an incandescent light bulb at 3573.16 degrees Kelvin.
#include <codecogs/engineering/heat_transfer/radiation/energy.h>
#include <stdio.h>
int main()
{
// the temperature of the Wolfram filament
double T = 3573.16;
// emissivity factor of the filament
double e = 0.39;
// display the total radiative energy
printf("Energy = %.5lf kW per sq. meter\n",
Engineering::Heat_Transfer::Radiation::energy(T, e)/1000.0);
return 0;
}Output:
Energy = 3603.96794 kW per sq. meter
Parameters:
| T | the absolute temperature of the body (Kelvin) |
| e | Default value = 1.0 |
Returns:
- the total radiative energy emitted by the body (Watt per square 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"
Authors:
- Grigore Bentea, Lucian Bentea (November 2006)
Source Code:
-
Last Modified: 18 Oct 07 @ 17:07 Page Rendered: 2008-05-08 23:38:27
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