Study of gas-dynamic processes of interaction of chordal gas jets with a vortex air flow

RELEVANCE. The nozzle block is the important element of block burners, determining the efficiency and reliability of the burners. Most commercially available nozzle blocks incorporate a disk with swirl vanes to generate flow turbulence; however, such disks create significant gas-dynamic drag.
THE PURPOSE. To study the influence of combustible gas feed angles (angle to the axis β and chord angle α) on gas distribution across the cylinder cross-sections, the degree of flow swirl, and the degree of vacuum using forced air supply by an axial fan without the use of swirl disks.
METHODS. The study was performed numerically for isothermal jets and flow in the ANSYS Fluent software package using the SST k-ω turbulence model.
RESULTS. The minimum variation coefficient for all considered configurations was found to be achieved at a swirl number of about S=0.4-0.5. Vacuum pressure depends on the combination of angles β and α, the maximum was achieved at β = 90°/α = 15°. The swirl rate depends on both the swirl number S and the combination of angles β and α, with each angle β having its own range of S variation to maintain the maximum swirl rate.
CONCLUSION. A configuration (β = 90°/α = 26°) was found to achieve a compromise between a high swirl (S=0.58-0.48), an extended low-pressure zone (with a peak point of -433 Pa) and uniform gas distribution in the sections of the nozzle block: variation coefficient varied within the range from 41% (1 caliber from the inlet section) to 13% (outlet section). The results of the work are of practical value for the design of burner devices and further calculations using the combustion model.

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