MODELING AND ANALYSIS OF THE EFFECT OF THE DEGREE OF FLOW TWIST ON THE AERODYNAMICS OF THE FLARE IN FIRE TUBE BOILERS

Abstract

Improving the energy efficiency and reliability of boiler equipment in housing and communal services is an urgent task, the solution of which is often associated with the modernization of outdated burners. The key factor determining the efficiency and durability of such boilers is the aerodynamics of the swirling torch created by the vortex burner. In this article, the influence of the degree of flow twist and the configuration of the air supply nozzles on the aerodynamic structure of the flow in the boiler furnace is investigated by computer modeling. The operating parameters of the burner's normal operation are accepted as boundary conditions. As a result of the simulation, velocity and turbulent kinetic energy fields were obtained for four air supply configurations corresponding to different values of the twist parameter. It has been established that it is precisely the aerodynamic asymmetry that leads to the deflection of the high-temperature core of the flare and the focusing of the heat flux on the local section of the shield pipes, which is the main cause of their local overheating, accelerated corrosion and erosion.

Subject of the study the subject of the study is the aerodynamic structure of a swirling torch in the furnace of a hot-water fire-tube boiler and its effect on thermal load, local overheating and wear of screen pipes.

Materials and methods: the research is based on the method of computer hydrogasdynamic modeling for the analysis of the aerodynamic structure of the swirling flow in the furnace chamber of the boiler. When constructing the model, the actual operating parameters of the standard vortex burner were taken into account. As part of the work, comparative modeling was carried out for several characteristic configurations of the air supply system, which differ in the location of open nozzles, which allows varying the degree of flow twist.

Results: as a result of the simulation, detailed velocity fields and the distribution of turbulent kinetic energy were obtained, which serve as the basis for the subsequent analysis of the structure of a swirling torch in the furnace of a hot-water fire-tube boiler. An asymmetric flow field with a recirculation zone is revealed. It is established that the aerodynamic asymmetry causes the deflection of the flare and local overheating of the shield tubes.

Conclusions: the aerodynamic asymmetry of the swirling flare, due to the degree of flow twist, is the main cause of local overheating and accelerated erosion of the screen pipes of fire tube boilers. To increase the efficiency and reliability of the equipment, it is necessary to optimize the geometry of the burner or the air supply system, aimed at equalizing the heat load. Joint analysis of turbulence and flow trajectories is an effective diagnostic method.