Design of a combined burner based on the patterns of interaction between an external swirling jet and an axial direct-flow jet

Abstract

The issue of providing fuel and energy resources to the population depends to a large extent on the wear of thermal networks, as well as heat-generating equip-ment, which, accordingly, forces the consumer to aban-don the centralized heating supply in favor of decentral-ized supply. However, low-power heat-generating units for autonomous consumers do not most of the time operate under the rated mode.The most promising way to solve the issue of energy conservation is to improve the utilization rate of fuel and energy resources in heat-generating units for decentral-ized heating systems that operate under non-stationary regimes.An experimental study of the velocity field of interac-tion between the coaxial axial direct-flow and external swirling jets has established that the performance efficien-cy of a heat-generating plant at a change in the thermal load could be improved by controlling the resulting veloci-ty field. For a more even distribution of temperature with-in the furnace volume, it has been proposed to supply fuel with an oxidizer in the furnace by the axial direct-flow and swirling coaxial jets.It was revealed that at a distance of 2 diameters of the axial branch pipe from the cut there occurs a trans-verse toroidal vortex. The appearance of such a vortex is explained by the emergence of low-pressure regions due to the different angles of opening of the swirling outer jet and axial direct-flow jet. The considered dependence of change in the gas flow rate at a decrease in power has demonstrated that the gas flow rate in the proposed burn-er is less than that in analogs (vortex burner or direct-flow burner) by 10‒15% when the power of the burner is reduced. At the same time, the specified advantage is lim-ited to the range of the burner’s power of 50‒130kW.The results reported confirm the possibility of con-trolling the velocity field and temperature distribution when the total fuel and oxidizer flow rate changes with-in the operational range of low-power heat-generating plants. The correspondence between the temperature field and the velocity field in the interaction of non-isothermal jets has also been shown