Heat flux and friction losses effects on natural circulation package boilers

The published literature on natural circulation in package boilers lacks a model that performs calculations for each circuit and determines circulation parameters for all circuits. This study presents a developed computational procedure capable of sizing and analyzing the performance of natural circulation package boilers to meet a specific load. Also; the study identifies the most critical circuit of a package boiler and determines the impact of heat flux, friction factor and tube plugging on the circulation ratio and wall temperature. The model was validated by comparing its results with experimental data. The results revealed that the Circuit 3 (The D-Tubes) is the most critical circuit. Plugging some of these tubes reduces the circulation ratio and increases the tube wall temperature significantly. The results indicate that the circulation ratio decreased by 20% and the wall temperature increased by 9.6% as a result of increase in the heat flux by 24%.