Selection of numerical methods for modeling free jets from a fire nozzle

Computational fluid dynamics methods enable the estimation of gas-liquid flow characteristics, particularly free jets, while accounting for various phenomena. The jets analyzed in this paper exhibit significant geometric dimensions and high initial velocities, which increase the computational complexity of the models used and extend their calculation time. The selection of numerical methods and their tuning parameters is based on a step-by-step increase in computational complexity to a level that meets quality criteria: ensuring an acceptable calculation time relative to the problem being solved and achieving accuracy determined by the deviation of the obtained results from the experimental target characteristics of the jets. The selection stages are outlined, including an experiment to evaluate the accuracy of the considered methods and the principles for aligning experimental and calculated characteristics for validation. The efficiency of the proposed selection scheme is demonstrated using the example of modeling free jets of fire extinguishing agent from a fire nozzle. The results of full-scale tests and calculations based on the selected models, conducted at the testing ground, are presented. The novelty lies in the formalization of computational fluid dynamics methods that ensure acceptable accuracy and calculation time for determining the trajectories of free jets relative to target characteristics. These methods can be applied in the development of automated systems for guiding the flow of fire extinguishing agent from a fire robot nozzle to specified areas of the protected space.