On the influence of the air supply on the thermal effectiveness of a PK-35
steam boiler.

D.Markov1, P.Stankov1, Y.Dinkov2 , S.Yotovski1
1 Technical University - Sofia, Dept. of  Hydroaerodynamics an Hydraulic
Machines,
"Kliment Ochridski" No 8, 1000 Sofia, BULGARIA
2 Kozloduy Nuclear Power Plant, Training Center, 3321 Kozloduy, BULGARIA

ABSTRACT

The paper deals with numerical simulations of a steam boiler PK 35/39/440,
operating at
different burner's conditions at nominal thermal load. The influence of both
air
excess
ratio (A) and relative burner's air intake asymmetry on the thermal
effectiveness was
investigated under the following operating conditions. The excess air A varies
in the
range of [0.98050,1.13950], the air supply of the burners was changed, so as
the
misbalance
in the air supply (dQb) to be within +-10% of their nominal supply. The
numerical code is
developed on the basis of 3D transport equations, k-e turbulence model,
Magnusen's Eddy
dissipation combustion model and discrete ordinate method for radiate heat
transfer modeling.
The influence of the air supply both in respect to the coefficient of air
excess
ratio and to
the asymmetry of the air supply in the two burners was analyzed. As a result
practically
oriented recommendations are given concerning the investigated furnace. The
obtained results
confirm the great importance of the proper air supply on the thermal
effectiveness.