Abstract
The hydrodynamic performance of once through boiler with spiral circuitry furnace (Benson type) spiraled around by inclined tubes, typically making a single pass around the full furnace from the hopper to the upper region where a transition is made to vertical tubes, has less been investigated. But in the academic and analytical points of view the appearance of unevenness in those parallel tubes may actually exist because of either the different tube length or the inherent gas temperature & projecting heat profiles. A special hydrodynamic calculation of the being constructed 900MW supercritical boiler in Shanghai Waigaoqiao PP has been done. The calculation is focused on determining of "Phase Change Point" under different boiler loads, which reveals the exact position of potential heat transfer deterioration in furnace. Meanwhile the instability, multivalency and pulsation of the two phases flow under partial loads have been analyzed, too. The results such as the maximum thermal deviation, the position of phase change point for heat most absorbed tubes as well as the maximum tube metal temperature in water wall tubes under different loads are shown in this paper.
