Numerical modeling of local heat transfer in the furnaces of tubular ovens, based on differential approximations for radiant heat transfer

1991 ◽  
Vol 60 (2) ◽  
pp. 237-242 ◽  
Author(s):  
A. M. Abdullin ◽  
D. B. Vafin
Keyword(s):  
Heat Transfer ◽  
Numerical Modeling ◽  
Local Heat Transfer ◽  
Radiant Heat ◽  
Local Heat ◽  
Radiant Heat Transfer

Radiant Interchange Between Circular Disks Having Arbitrarily Different Temperatures

1961 ◽  
Vol 83 (4) ◽  
pp. 494-502 ◽  
Author(s):  
E. M. Sparrow ◽  
J. L. Gregg
Keyword(s):  
Heat Transfer ◽  
Numerical Solutions ◽  
Local Heat Transfer ◽  
Disk Surface ◽  
Radiant Heat ◽  
Local Heat ◽  
Radiant Heat Transfer ◽  
Disk Radius ◽  
Integral Equation Formulation ◽  
Different Temperatures

The problem of radiant heat transfer between parallel disks has been analyzed by generalizing the standard gray-body enclosure theory. In particular, the assumption that the radiant flux leaving a surface and the local heat flux are uniformly distributed over the surface has been lifted by an integral equation formulation. It has been shown that the general problem of disks at arbitrarily different temperatures can be conveniently broken down into two subproblems, each of which can be solved independently of the temperature level. Numerical solutions of the governing integral equations have been carried out for spacing ratios h/R (h = spacing, R = disk radius) ranging from 5.0 to 0.05 and for emissivities ranging from 0.1 to 0.9. Local heat-transfer results have been presented which, depending on spacing and emissivity, display marked variations over the disk surface. Over-all heat-transfer results have been calculated and compared with the predictions of the standard simplified enclosure theory. These predictions of the simplified theory were found to be unexpectedly good, especially in view of the large surface variations of the local heat transfer.

Paper 12: Derivation of Furnace Heat Transfer from Fluid Dynamic Behaviour

1965 ◽  
Vol 180 (10) ◽  
pp. 109-117
Author(s):  
D. Anson
Keyword(s):  
Heat Transfer ◽  
Dynamic Behaviour ◽  
Fluid Dynamic ◽  
Radiant Heat ◽  
Local Heat ◽  
Radiant Heat Transfer ◽  
Release Rates ◽  
Air Mixing ◽  
Mixing Rates ◽  
The Relationship

The principles underlying radiant heat transfer in boiler furnaces are fundamentally simple, but their application requires a knowledge of empirical quantities describing the emissivity of the flame and the boiler surfaces and the relationship between their geometries. This paper draws attention to the dependence of local heat release rates on fuel/air mixing. In the case of a downshot coal-fired furnace, the performance of which was investigated in detail, the size and position of the effective flame envelope could be derived from a knowledge of the flow and mixing rates. These in turn should be capable of being measured on isothermal models, and research should be directed to this end.

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