Abstract
Water circulation characteristics, for a newly designed 4-pass 300 BHP (Boiler Horse Power) firetube boiler with a non-symmetric arrangement of tube passes 3 and 4, are investigated in this paper by means of measured furnace wall temperatures for different boiler firing conditions. Vapor production rate and intensity, at each of the 28 temperature measurement nodes, is approximated using the nodal temperature in conjunction with a nucleate boiling heat transfer mode on the water side of the furnace. Defining an attraction force that is proportional to the relative difference of the evaporation intensity between two nodes and inversely proportional to the distance between, the two-dimensional components of the attraction force can be calculated. Integrating all attraction force vectors between a node and the surrounding nodes produces a representative attraction force vector at the node. Similar calculation of the attraction force vectors at all of the temperature nodes on the furnace wall will characterize the water circulation near the boiler furnace. Investigations of the analysis results reveal various complicated non-symmetric water circulation patterns for different boiler firing conditions. Consequently, the analysis methods employed in this paper can be used to predict and improve the water circulation in a firetube boiler, particularly with regard to the placement of the boiler feed-water inlet location.
