Abstract
There is often residual whirl at the furnace outlet of the tangentially-fired furnaces. It has serious influence on the safe operation of the boiler. It is well known that the large temperature imbalance of the flue gas and steam may be a serious threat to the safe operation of the superheater and the reheater. In the counter-tangential operation, some counter-tangential air-streams are used to depress the residual whirl intensity. However, there is some misunderstanding in counter-tangential operation, which does not take account of the particularities of the tangential firing. It only eliminates the whirl by itself. The controlled whirl method is put forward in this paper, which not only keep the advantage of the corner tangential firing, but also effectively controls the residual spin intensity at the furnace outlet. The numerical simulation was used in this paper to discuss some basic principles. It is shown how the angular momentum flux is influenced when various layer second air is used to depress whirl.
