Radiation heat transfer Stefan-Boltzmann constant

The thermal radiation heat-transfer rate, rad, emitted by the IR emitter is equal to Aeo- T , where A is the emitter surface area, s is the emissivity of the emitter, cr is the Stefan-Boltzmann constant (5.67x10 W/m /K ), and T is the temperature of the emitter. As the energy emitted varies with the fourth power of temperature, the heating power... 

Design Methods for Calciners In indirect-heated calciners, heat transfer is primarily by radiation from the cyhnder wall to the solids bed. The thermal efficiency ranges from 30 to 65 percent. By utilization of the furnace exhaust gases for preheated combustion air, steam produc tion, or heat for other process steps, the thermal efficiency can be increased considerably. The limiting factors in heat transmission he in the conductivity and radiation constants of the shell metal and solids bed. If the characteristics of these are known, equipment may be accurately sized by employing the Stefan-Boltzmann radiation equation. Apparent heat-transfer coefficients will range from 17 J/(m s K) in low-temperature operations to 8.5 J/(m s K) in high-temperature processes. 

---