Optimizing the temperature stress for the furnace volume of a fire-tube boiler

Abstract

A reasonable choice of the temperature stress for the furnace volume allows providing the required value of the gas temperature at the furnace outlet, as well as the high quality of the fuel combustion process with an optimal excess air ratio. The goal of the research is to study the temperature stress for the furnace of a fire-tube boiler and its effect on the boiler’s design used for heat supply to agricultural enterprises. In order to study the effect of temperature stress and the furnace’s proportions on the ratio of heating surface areas, the design resistance is checked. Calculations for sectional water fire-tube boilers with different proportions of the furnace were performed for various thermal loads of the same furnace volume. Each heating surface was calculated using the approximate method, based on the chord method in this case. During the calculation process, the temperature of the flue gases at the exit from the heating surface was first set, and then refined by successive approximations. In order to draw up the overall balance of the boiler, another global approximation was made. The temperature determined at the exit from the last heating surface was set at the start of the calculation, i.e. in the heat balance, where it affects the loss with flue gases and the efficiency of the boiler. It was determined that the optimal values of the temperature stress for the furnace can vary greatly, depending on the selected ratio of the flue length to its diameter